IDIMS/GEOPAK: Users manual for a geophysical data display and analysis system

NASA Technical Reports Server (NTRS)

Libert, J. M.

1982-01-01

The application of an existing image analysis system to the display and analysis of geophysical data is described, the potential for expanding the capabilities of such a system toward more advanced computer analytic and modeling functions is investigated. The major features of the IDIMS (Interactive Display and Image Manipulation System) and its applicability for image type analysis of geophysical data are described. Development of a basic geophysical data processing system to permit the image representation, coloring, interdisplay and comparison of geophysical data sets using existing IDIMS functions and to provide for the production of hard copies of processed images was described. An instruction manual and documentation for the GEOPAK subsystem was produced. A training course for personnel in the use of the IDIMS/GEOPAK was conducted. The effectiveness of the current IDIMS/GEOPAK system for geophysical data analysis was evaluated.

Research and career opportunities in the geophysical sciences for physics students

NASA Astrophysics Data System (ADS)

Nyblade, Andrew

2008-10-01

The field of geophysics involves using most branches of physics to investigate the physical structure and process that characterize the solid and fluid parts of our planet. Major advances in geophysics have come about from physicists crossing disciplinary boundaries and using their skills and knowledge to address first-order problems about the nature and structure of our planet and how the planet has changed over time. Indeed, some of the largest scientific breakthroughs in geophysics have come from physicists. As a way to introduce students to the field of geophysics and to provide them with information about research and career opportunities in geophysics, this talk will focus on one area of geophysics, seismology. This is an area of geophysics that has not only been instrumental in advancing our understanding of solid Earth structure and processes, but one that also has an applied side used for oil, gas and mineral exploration, as well as for environmental work. Examples of research projects involving seismic wave propagation and tomographic imaging will be presented, along the short descriptions of career opportunities in industry, government and academic institutions. In collaboration with Solomon Bililign, North Carolina A&T State University.

Multidisciplinary approach for the characterization of landslides in volcanic areas - a case study from the Palma Sola-Chiconquiaco Mountain Range, Mexico

NASA Astrophysics Data System (ADS)

Wilde, Martina; Rodríguez Elizarrarás, Sergio R.; Morales Barrera, Wendy V.; Schwindt, Daniel; Bücker, Matthias; Flores Orozco, Adrián; García García, Emilio; Pita de la Paz, Carlos; Terhorst, Birgit

2017-04-01

The Palma Sola-Chiconquiaco mountain range, situated in the State of Veracruz, Mexico, is highly susceptible to landslides, which is evidenced by the high frequency of landslide events of different sizes. The study area is located near the Gulf of Mexico coastline in the eastern sector of the Trans Mexican Volcanic Belt. There, landslide triggers are intense rainfalls related to tropical storms and hurricanes. Steeper slopes are commonly affected by rockfalls, whereas moderate slopes, covered by massive slope deposits, are affected by shallow as well as deep seated landslides. Some of the landslides in the slope deposits reach dimensions of more than 1000 m in length and depths of over 30 m. The heterogeneous parent material as well as older slide masses hamper the detailed characterization of the involved materials. Therefore, in this study, a multidisciplinary approach is applied that integrates geomorphological, geological, and geophysical data. The aim is the reconstruction of process dynamics by analyzing the geomorphological situation and subsurface conditions before and after the event. The focus lies on the identification of past landslide areas, which represent areas with high susceptibility for the reactivation of old slide masses. Furthermore, the analysis of digital terrain models, generated before the landslide event, indicate initial movements like extension cracks, which are located close to the current scarp area. In order to characterize the subsurface of slide masses geophysical investigations are applied. The geophysical survey consists of a total of nine profiles covering relevant key features of the large affected area. Along these profiles, electrical resistivity tomography (ERT) and seismic refraction tomography (SRT) data were collected. Both, electrical and seismic images reveal a sharp contrast between relatively loose and dry material of the slide mass (high resistivities and low seismic velocities) and the former land surface that is characterized by significantly reduced resistivities and higher seismic velocities. This contrast allows to establish the thicknesses of slope deposits and geological layers along all geophysical profiles. Furthermore, the investigations are complemented by a high resolution digital terrain model of the landslide and its surroundings, which was reconstructed from orthophotos derived from unmanned aerial vehicle photogrammetry.

Airborne geophysical surveys conducted in western Nebraska, 2010: contractor reports and data

USGS Publications Warehouse

,

2014-01-01

This report contains three contractor reports and data files for an airborne electromagnetic survey flown from June 28 to July 7, 2010. The first report; “SkyTEM Survey: Nebraska, USA, Data” describes data aquisition and processing from a time-domain electromagnetic and magnetic survey performed by SkyTEM Canada, Inc. (the North American SkyTEM subsidiary), in western Nebraska, USA. Digital data for this report are given in Appendix 1. The airborne geophysical data from the SkyTEM survey subsequently were processed and inverted by Aarhus Geophysics ApS, Aarhus, Denmark, to produce resistivity depth sections along each flight line. The result of that processing is described in two reports presented in Appendix 2, “Processing and inversion of SkyTEM data from USGS Area UTM–13” and “Processing and inversion of SkyTEM data from USGS Area UTM–14.” Funding for these surveys was provided by the North Platte Natural Resources District, the South Platte Natural Resources District, and the Twin Platte Natural Resources District, in Scottsbluff, Sidney, and North Platte, Nebraska, respectively. Any additional information concerning the geophysical data may be obtained from the U.S. Geological Survey Crustal Geophysics and Geochemistry Science Center, Denver Colorado.

Development and implementation of the software for visualization and analysis of data geophysical loggers

NASA Astrophysics Data System (ADS)

Gordeev, V. F.; Malyshkov, S. Yu.; Botygin, I. A.; Sherstnev, V. S.; Sherstneva, A. I.

2017-11-01

The general trend of modern ecological geophysics is changing priorities towards rapid assessment, management and prediction of ecological and engineering soil stability as well as developing brand new geophysical technologies. The article describes researches conducted by using multi-canal geophysical logger MGR-01 (developed by IMCES SB RAS), which allows to measure flux density of very low-frequency electromagnetic radiation. It is shown that natural pulsed electromagnetic fields of the earthen lithosphere can be a source of new information on Earth's crust and processes in it, including earthquakes. The device is intended for logging electromagnetic processes in Earth's crust, geophysical exploration, finding structural and lithological inhomogeneities, monitoring the geodynamic movement of Earth's crust, express assessment of seismic hazards. The data is gathered automatically from observation point network in Siberia

Delineation of karst terranes in complex environments: Application of modern developments in the wavelet theory and data mining

NASA Astrophysics Data System (ADS)

Alperovich, Leonid; Averbuch, Amir; Eppelbaum, Lev; Zheludev, Valery

2013-04-01

Karst areas occupy about 14% of the world land. Karst terranes of different origin have caused difficult conditions for building, industrial activity and tourism, and are the source of heightened danger for environment. Mapping of karst (sinkhole) hazards, obviously, will be one of the most significant problems of engineering geophysics in the XXI century. Taking into account the complexity of geological media, some unfavourable environments and known ambiguity of geophysical data analysis, a single geophysical method examination might be insufficient. Wavelet methodology as whole has a significant impact on cardinal problems of geophysical signal processing such as: denoising of signals, enhancement of signals and distinguishing of signals with closely related characteristics and integrated analysis of different geophysical fields (satellite, airborne, earth surface or underground observed data). We developed a three-phase approach to the integrated geophysical localization of subsurface karsts (the same approach could be used for following monitoring of karst dynamics). The first phase consists of modeling devoted to compute various geophysical effects characterizing karst phenomena. The second phase determines development of the signal processing approaches to analyzing of profile or areal geophysical observations. Finally, at the third phase provides integration of these methods in order to create a new method of the combined interpretation of different geophysical data. In the base of our combine geophysical analysis we put modern developments in the wavelet technique of the signal and image processing. The development of the integrated methodology of geophysical field examination will enable to recognizing the karst terranes even by a small ratio of "useful signal - noise" in complex geological environments. For analyzing the geophysical data, we used a technique based on the algorithm to characterize a geophysical image by a limited number of parameters. This set of parameters serves as a signature of the image and is to be utilized for discrimination of images containing karst cavity (K) from the images non-containing karst (N). The constructed algorithm consists of the following main phases: (a) collection of the database, (b) characterization of geophysical images, (c) and dimensionality reduction. Then, each image is characterized by the histogram of the coherency directions. As a result of the previous steps we obtain two sets K and N of the signatures vectors for images from sections containing karst cavity and non-karst subsurface, respectively.

Active tectonics

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

Not Available

1986-01-01

This study is part of a series of Studies in Geophysics that have been undertaken for the Geophysics Research Forum by the Geophysics Study Committee. One purpose of each study is to provide assessments from the scientific community to aid policymakers in decisions on societal problems that involve geophysics. An important part of such assessments is an evaluation of the adequacy of current geophysical knowledge and the appropriateness of current research programs as a source of information required for those decisions. The study addresses our current scientific understanding of active tectonics --- particularly the patterns and rates of ongoing tectonicmore » processes. Many of these processes cannot be described reasonably using the limited instrumental or historical records; however, most can be described adequately for practical purposes using the geologic record of the past 500,000 years. A program of fundamental research focusing especially on Quaternary tectonic geology and geomorphology, paleoseismology, neotectonics, and geodesy is recommended to better understand ongoing, active tectonic processes. This volume contains 16 papers. Individual papers are indexed separately on the Energy Database.« less

Attaining insight into interactions between hydrologic model parameters and geophysical attributes for national-scale model parameter estimation

NASA Astrophysics Data System (ADS)

Mizukami, N.; Clark, M. P.; Newman, A. J.; Wood, A.; Gutmann, E. D.

2017-12-01

Estimating spatially distributed model parameters is a grand challenge for large domain hydrologic modeling, especially in the context of hydrologic model applications such as streamflow forecasting. Multi-scale Parameter Regionalization (MPR) is a promising technique that accounts for the effects of fine-scale geophysical attributes (e.g., soil texture, land cover, topography, climate) on model parameters and nonlinear scaling effects on model parameters. MPR computes model parameters with transfer functions (TFs) that relate geophysical attributes to model parameters at the native input data resolution and then scales them using scaling functions to the spatial resolution of the model implementation. One of the biggest challenges in the use of MPR is identification of TFs for each model parameter: both functional forms and geophysical predictors. TFs used to estimate the parameters of hydrologic models typically rely on previous studies or were derived in an ad-hoc, heuristic manner, potentially not utilizing maximum information content contained in the geophysical attributes for optimal parameter identification. Thus, it is necessary to first uncover relationships among geophysical attributes, model parameters, and hydrologic processes (i.e., hydrologic signatures) to obtain insight into which and to what extent geophysical attributes are related to model parameters. We perform multivariate statistical analysis on a large-sample catchment data set including various geophysical attributes as well as constrained VIC model parameters at 671 unimpaired basins over the CONUS. We first calibrate VIC model at each catchment to obtain constrained parameter sets. Additionally, parameter sets sampled during the calibration process are used for sensitivity analysis using various hydrologic signatures as objectives to understand the relationships among geophysical attributes, parameters, and hydrologic processes.

Use of geophysical methods in man-made hazard management strategies. Case study from Ploiesti city, Romania

NASA Astrophysics Data System (ADS)

Chitea, F.; Anghelache, M. A.; Ioane, D.

2010-05-01

Identification of damages/changes that are affecting the underground water quality due to the effect of anthropogenic activities is often done after environmental problems have become evident, water potability being strongly affected. In this paper we will discuss the necessity of implementing non-invasive and non-destructive investigation tools in different parts of the management plan for urban areas affected or with high risk of being affected by man-made hazards. Geophysical investigations represent nowadays a useful tool in environmental problems that affect soil and underground water in urban areas, as useful information can be obtained regarding the following aspects: - detection of affected areas, especially when the effect or hazard sources are not visible at the surface - zonation of the area (severely affected zone or less affected) - investigation of the area (details on affected surface and affected soil depth) - location of "hidden" sources (illegal waste dump sites, petroleum transport or transfer pipes, etc) - estimation of soil and underground damages by monitoring petrophysical markers - risk evaluation (estimations on the direction and speed of environmental problems development, estimations of amplifying negative effects) - recovery from the man-made hazard of a certain area (monitoring information can give information about natural attenuation of the environmental problems or efficacy of resilience program) - preparedness for man-made hazards (prediction). Functionality of the above mentioned plans of geophysical applicability in identifying and characterizing the effect of anthropogenic hazards which affect soil and underground water quality has been tested in Ploiesti city, Romania. In this urban area, as well as in surrounding villages, water potability is severely affected because of the oil-products contamination caused by the refinery facilities developed in the area. Oil-contamination is a major problem environmental problem, due to the fact that affected area is continuously expanding as a consequence of contaminant transport by the underground water. Hydrogeologically the research area is located in the alluvium of one of the main hydrostructures of Romania, which holds important water resources. Preliminary investigations made in the Ploiesti city area, has shown the high vulnerability of the aquifer to pollution and it was detected a highly contaminated area. By detailed investigations made using geophysical investigations in the test-zone, it was possible the detection of the presence of the particular type of pollutants and a map with area zonation has been produced. Appliance of geophysical investigations in environmental strategies concerning underground water pollution should be added to the ones obtained by direct investigations for risk evaluation and remediation strategies in cases of man made hazards. Acknowledgements: The research was performed with financial support from MENER (project nr. 725/ 2006) and CNCSIS-UEFISCU (project nr. 244/2007)

Introduction to the JEEG Agricultural Geophysics special issue

USDA-ARS?s Scientific Manuscript database

Recent advancements such as the availability of personal computers, technologies to store/process large amounts of data, the GPS, and GIS have now made geophysical methods practical for agricultural use. Consequently, there has been a rapid expansion of agricultural geophysics research just over the...

An array processing system for lunar geochemical and geophysical data

NASA Technical Reports Server (NTRS)

Eliason, E. M.; Soderblom, L. A.

1977-01-01

A computerized array processing system has been developed to reduce, analyze, display, and correlate a large number of orbital and earth-based geochemical, geophysical, and geological measurements of the moon on a global scale. The system supports the activities of a consortium of about 30 lunar scientists involved in data synthesis studies. The system was modeled after standard digital image-processing techniques but differs in that processing is performed with floating point precision rather than integer precision. Because of flexibility in floating-point image processing, a series of techniques that are impossible or cumbersome in conventional integer processing were developed to perform optimum interpolation and smoothing of data. Recently color maps of about 25 lunar geophysical and geochemical variables have been generated.

Geophysics: The Earth in Space. A Guide for High School Students.

ERIC Educational Resources Information Center

American Geophysical Union, Washington, DC.

Geophysics is the application of physics, chemistry, and mathematics to the problems and processes of the earth, from its innermost core to its outermost environs in space. Fields within geophysics include the atmospheric sciences; geodesy; geomagnetism and paleomagnetism; hydrology; oceanography; planetology; seismology; solar-planetary…

Karst aquifer characterization using geophysical remote sensing of dynamic recharge events

NASA Astrophysics Data System (ADS)

Grapenthin, R.; Bilek, S. L.; Luhmann, A. J.

2017-12-01

Geophysical monitoring techniques, long used to make significant advances in a wide range of deeper Earth science disciplines, are now being employed to track surficial processes such as landslide, glacier, and river flow. Karst aquifers are another important hydrologic resource that can benefit from geophysical remote sensing, as this monitoring allows for safe, noninvasive karst conduit measurements. Conduit networks are typically poorly constrained, let alone the processes that occur within them. Geophysical monitoring can also provide a regionally integrated analysis to characterize subsurface architecture and to understand the dynamics of flow and recharge processes in karst aquifers. Geophysical signals are likely produced by several processes during recharge events in karst aquifers. For example, pressure pulses occur when water enters conduits that are full of water, and experiments suggest seismic signals result from this process. Furthermore, increasing water pressure in conduits during recharge events increases the load applied to conduit walls, which deforms the surrounding rock to yield measureable surface displacements. Measureable deformation should also occur with mass loading, with subsidence and rebound signals associated with increases and decreases of water mass stored in the aquifer, respectively. Additionally, geophysical signals will likely arise with turbulent flow and pore pressure change in the rock surrounding conduits. Here we present seismic data collected during a pilot study of controlled and natural recharge events in a karst aquifer system near Bear Spring, near Eyota, MN, USA as well as preliminary model results regarding the processes described above. In addition, we will discuss an upcoming field campaign where we will use seismometers, tiltmeters, and GPS instruments to monitor for recharge-induced responses in a FL, USA karst system with existing cave maps, coupling these geophysical observations with hydrologic and meteorologic data to map and characterize conduits and other features of the larger karst system and to monitor subsurface flow dynamics during recharge events.

Geophysical monitoring technology for CO2 sequestration

NASA Astrophysics Data System (ADS)

Ma, Jin-Feng; Li, Lin; Wang, Hao-Fan; Tan, Ming-You; Cui, Shi-Ling; Zhang, Yun-Yin; Qu, Zhi-Peng; Jia, Ling-Yun; Zhang, Shu-Hai

2016-06-01

Geophysical techniques play key roles in the measuring, monitoring, and verifying the safety of CO2 sequestration and in identifying the efficiency of CO2-enhanced oil recovery. Although geophysical monitoring techniques for CO2 sequestration have grown out of conventional oil and gas geophysical exploration techniques, it takes a long time to conduct geophysical monitoring, and there are many barriers and challenges. In this paper, with the initial objective of performing CO2 sequestration, we studied the geophysical tasks associated with evaluating geological storage sites and monitoring CO2 sequestration. Based on our review of the scope of geophysical monitoring techniques and our experience in domestic and international carbon capture and sequestration projects, we analyzed the inherent difficulties and our experiences in geophysical monitoring techniques, especially, with respect to 4D seismic acquisition, processing, and interpretation.

30 CFR 250.175 - When may the Regional Supervisor grant an SOO?

Code of Federal Regulations, 2010 CFR

2010-07-01

... processing or interpretation of the geophysical information with the objective of identifying a potential... processing or interpretation of existing geophysical data or information; (ii) acquire, process, or interpret... mean sea level (TVD SS) when all of the following conditions are met: (1) The lease was issued with a...

Solar Wind Monitor--A School Geophysics Project

ERIC Educational Resources Information Center

Robinson, Ian

2018-01-01

Described is an established geophysics project to construct a solar wind monitor based on a nT resolution fluxgate magnetometer. Low-cost and appropriate from school to university level it incorporates elements of astrophysics, geophysics, electronics, programming, computer networking and signal processing. The system monitors the earth's field in…

Pitfalls and Limitations in the Interpretation of Geophysical Images for Hydrologic Properties and Processes

NASA Astrophysics Data System (ADS)

Day-Lewis, F. D.

2014-12-01

Geophysical imaging (e.g., electrical, radar, seismic) can provide valuable information for the characterization of hydrologic properties and monitoring of hydrologic processes, as evidenced in the rapid growth of literature on the subject. Geophysical imaging has been used for monitoring tracer migration and infiltration, mapping zones of focused groundwater/surface-water exchange, and verifying emplacement of amendments for bioremediation. Despite the enormous potential for extraction of hydrologic information from geophysical images, there also is potential for misinterpretation and over-interpretation. These concerns are particularly relevant when geophysical results are used within quantitative frameworks, e.g., conversion to hydrologic properties through petrophysical relations, geostatistical estimation and simulation conditioned to geophysical inversions, and joint inversion. We review pitfalls to interpretation associated with limited image resolution, spatially variable image resolution, incorrect data weighting, errors in the timing of measurements, temporal smearing resulting from changes during data acquisition, support-volume/scale effects, and incorrect assumptions or approximations involved in modeling geophysical or other jointly inverted data. A series of numerical and field-based examples illustrate these potential problems. Our goal in this talk is to raise awareness of common pitfalls and present strategies for recognizing and avoiding them.

Geological and Geophysical Analysis of the Processes Ground Cracking and Associated Risks in Urban Basins in the Eastern and Northern of Jalisco Block, Mexico.

NASA Astrophysics Data System (ADS)

Suarez-Plascencia, C.

2016-12-01

The Jalisco Block (JB) is located in the western sector of Mexican Volcanic Belt; it is bounded on the east by the Colima graben-Zacoalco and apparently the north by the River Grande de Santiago. Three landform are regionally identified: mountain areas, piedmont and plains formed by deposits of tuffs, volcanic ash and sediment filled. These plains have been progressively urbanized since the sixteenth century; they were built in around the Guadalajara Metropolitan Area, as well as small towns like Sayula, Ciudad Guzman, Zacoalco, Jocotepec and nearby villages, in which all together are populated by about 6 million people. Since 1912 there are records of damages by the continuous formation of ground cracking, this process has increased over the past two decades, affecting natural soil, agricultural areas, urban areas and infrastructure of roads and highways. These cracks generally have a SW-NE orientation similar with the alignment of regional geological structures. They are characterized by settlements and forming steps of a few centimeters, with lengths from 300 to 1000 m and depths of a few centimeters to 15 meters and width of up to 2.5 m. Formed mainly during the rainy season from June to October each year. Recent damages have generated losses of several hundreds of thousands of dollars, especially in Ciudad Guzman, located in southern BJ, where a crack of 2.5 km was observed in 2012 and it has long affected the downtown area, the town of Nextipac-Tesistan, municipality of Zapopan in the northern sector of JB. This territory is formed by a thick deposit of pumice tuffs, which has presented cracks in the years 1912, 1975, 1987, 2004 and 2015, affecting also agricultural and urban areas. The paper will presents results which will analyze and discern through geological, geophysical and with technology of geographic information, the origin of these cracks, which can be associated with active tectonic structures, geo-hydrological processes, extraction of underground water or a combination of these three factors. Mapping of risk areas affected by these geological processes will be presented.

Highlights from the SoilCAM project: Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring

NASA Astrophysics Data System (ADS)

French, H. K.; van der Zee, S. E. A. T. M.; Wehrer, M.; Godio, A.; Pedersen, L. B.; Toscano, G.

2012-04-01

The SoilCAM project (Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring 2008-2012, EU-FP7-212663) is aimed at improving current methods for monitoring contaminant distribution and biodegradation in the subsurface. At two test sites, Oslo airport Gardermoen in Norway and the Trecate site in Italy, a number of geophysical techniques, lysimeter and other soil and water sampling techniques as well as numerical flow and transport modelling have been combined at different scales in order to characterise flow transport processes in the unsaturated and saturated zones. Laboratory experiments have provided data on physical and bio-geo-chemical parameters for use in models and to select remediation methods. The geophysical techniques were used to map geological heterogeneities and also conduct time-lapse measurements of processes in the unsaturated zone. Both cross borehole and surface electrodes were used for electrical resistivity and induced polarisation surveys. The geophysical surveys showed clear indications of areas highly affected by de-icing chemicals along the runway at Oslo airport. The time lapse measurements along the runway at the airport show infiltration patterns during snowmelt and are used to validate 2D unsaturated flow and transport simulations using SUTRA. The Orchestra model is used to describe the complex interaction between bio-geo-chemical processes in a 1D profile along the runway. The presence of installations such as a membrane along the runway highly affects the flow pattern and challenges the capacity of the numerical code. Smaller scale field site measurements have revealed the increase of iron and manganese during degradation of de-icing chemicals. The use of Nitrate to increase red-ox potential was tested, but results have not been analysed yet. So far it cannot be concluded that degradation process can be quantified indirectly by geophysical monitoring. At the Trecate site a combination of georadar, electrical resistivity and radio magneto telluric provided a broad outline of the geology down to 50 m, there is a good consistency in the data in the overlapping part, and more deep samples would be required to validate the geological interpretation of the data. Anomalies in the Induced polarisation and electrical resistivity data from the cross borehole measurements indicate where the remaining crude oil can be found. Water samples from multilevel samplers reveal crude oil present in emulsion in the zone of groundwater fluctuations, highlighting the importance of colloidal transport. Geochemistry of the groundwater clearly indicates degradation of hydrocarbons under iron- and sulphate reducing conditions. Modflow has been used to simulate the regional groundwater flow and transport in the area. An overview of the work that has been conducted and main highlights of the results so far will be presented.

Autonomous cloud based site monitoring through hydro geophysical data assimilation, processing and result delivery

NASA Astrophysics Data System (ADS)

Versteeg, R.; Johnson, D. V.; Rodzianko, A.; Zhou, H.; Dafflon, B.; Leger, E.; de Kleine, M.

2017-12-01

Understanding of processes in the shallow subsurface requires that geophysical, biogeochemical, hydrological and remote sensing datasets are assimilated, processed and interpreted. Multiple enabling software capabilities for process understanding have been developed by the science community. These include information models (ODM2), reactive transport modeling (PFLOTRAN, Modflow, CLM, Landlab), geophysical inversion (E4D, BERT), parameter estimation (PEST, DAKOTA), visualization (ViSiT, Paraview, D3, QGIS) as well as numerous tools written in python and R for petrophysical mapping, stochastic modeling, data analysis and so on. These capabilities use data collected using sensors and analytical tools developed by multiple manufacturers which produce many different measurements. While scientists obviously leverage tools, capabilities and lessons learned from one site at other sites, the current approach to site characterization and monitoring is very labor intensive and does not scale well. Our objective is to be able to monitor many (hundreds - thousands) of sites. This requires that monitoring can be done in a near time, affordable, auditable and essentially autonomous manner. For this we have developed a modular vertically integrated cloud based software framework which was designed from the ground up for effective site and process monitoring. This software framework (PAF - Predictive Assimilation Framework) is multitenant software and provides automation of data ingestion, processing and visualization of hydrological, geochemical and geophysical (ERT/DTS) data. The core organizational element of PAF is a project/user one in which capabilities available to users are controlled by a combination of available data and access permissions. All PAF capabilities are exposed through APIs, making it easy to quickly add new components. PAF is fully integrated with newly developed autonomous electrical geophysical hardware and thus allows for automation of electrical geophysical ingestion and processing and the ability for co analysis and visualization of the raw and processed data with other data of interest (e.g. soil temperature, soil moisture, precipitation). We will demonstrate current PAF capabilities and discuss future efforts.

Data processing system for the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory-F (OGO-F) satellite

NASA Technical Reports Server (NTRS)

Cronin, A. G.; Delaney, J. R.

1973-01-01

The system is discussed which was developed to process digitized telemetry data from the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory (OGO-F) Satellite. Functional descriptions and operating instructions are included for each program in the system.

The Global Geophysical Fluids Center of IERS (and its Special Bureau for Mantle)

NASA Astrophysics Data System (ADS)

Chao, B. F.

2002-12-01

The Global Geophysical Fluids Center (GGFC) was established by the International Earth Rotation Service (IERS) on IERS's 10th anniversary day January 1, 1998, in an effort to expand IERS's services to the scientific community. Under the GGFC, eight Special Bureaus (SB) have been selected, each to be responsible for research and data service activities pertaining to mass transports and related geophysical processes in specific components of the Earth system, or "global geophysical fluids," including the atmosphere, oceans, solid Earth, core, and geophysical processes of gravity, loading, tides and hydrological cycles. GGFC and the SBs have the responsibility of supporting, facilitating, and providing services to the worldwide research community, in areas related to the variations in Earth rotation, gravity field and geocenter that are caused by mass transport in the global geophysical fluids. These minute variations have been observed by various space geodetic techniques, as effective remote sensing tools, with ever increasing precision/accuracy and temporal/spatial resolution. The GGFC and SBs have organized dedicated workshops and special sessions at international conferences, published articles, and held regular business meetings. The SBs maintain individual website for data services and information exchanges. See URL bowie.gsfc.nasa.gov/ggfc/. In particular, the SB for Mantle focuses on large-scale mass redistributions that occur in the mantle in association with various dynamic processes, including seismic activities, the post-glacial rebound, and mantle convections.

Geophysical Factor Resolving of Rainfall Mechanism for Super Typhoons by Using Multiple Spatiotemporal Components Analysis

NASA Astrophysics Data System (ADS)

Huang, Chien-Lin; Hsu, Nien-Sheng

2016-04-01

This study develops a novel methodology to resolve the geophysical cause of typhoon-induced rainfall considering diverse dynamic co-evolution at multiple spatiotemporal components. The multi-order hidden patterns of complex hydrological process in chaos are detected to understand the fundamental laws of rainfall mechanism. The discovered spatiotemporal features are utilized to develop a state-of-the-art descriptive statistical model for mechanism validation, modeling and further prediction during typhoons. The time series of hourly typhoon precipitation from different types of moving track, atmospheric field and landforms are respectively precede the signal analytical process to qualify each type of rainfall cause and to quantify the corresponding affected degree based on the measured geophysical atmospheric-hydrological variables. This study applies the developed methodology in Taiwan Island which is constituted by complex diverse landform formation. The identified driving-causes include: (1) cloud height to ground surface; (2) co-movement effect induced by typhoon wind field with monsoon; (3) stem capacity; (4) interaction between typhoon rain band and terrain; (5) structural intensity variance of typhoon; and (6) integrated cloudy density of rain band. Results show that: (1) for the central maximum wind speed exceeding 51 m/sec, Causes (1) and (3) are the primary ones to generate rainfall; (2) for the typhoon moving toward the direction of 155° to 175°, Cause (2) is the primary one; (3) for the direction of 90° to 155°, Cause (4) is the primary one; (4) for the typhoon passing through mountain chain which above 3500 m, Cause (5) is the primary one; and (5) for the moving speed lower than 18 km/hr, Cause (6) is the primary one. Besides, the multiple geophysical component-based precipitation modeling can achieve 81% of average accuracy and 0.732 of average correlation coefficient (CC) within average 46 hours of duration, that improve their predictability.

Geophysical characterisation of the groundwater-surface water interface

NASA Astrophysics Data System (ADS)

McLachlan, P. J.; Chambers, J. E.; Uhlemann, S. S.; Binley, A.

2017-11-01

Interactions between groundwater (GW) and surface water (SW) have important implications for water quantity, water quality, and ecological health. The subsurface region proximal to SW bodies, the GW-SW interface, is crucial as it actively regulates the transfer of nutrients, contaminants, and water between GW systems and SW environments. However, geological, hydrological, and biogeochemical heterogeneity in the GW-SW interface makes it difficult to characterise with direct observations. Over the past two decades geophysics has been increasingly used to characterise spatial and temporal variability throughout the GW-SW interface. Geophysics is a powerful tool in evaluating structural heterogeneity, revealing zones of GW discharge, and monitoring hydrological processes. Geophysics should be used alongside traditional hydrological and biogeochemical methods to provide additional information about the subsurface. Further integration of commonly used geophysical techniques, and adoption of emerging techniques, has the potential to improve understanding of the properties and processes of the GW-SW interface, and ultimately the implications for water quality and environmental health.

Sustainable urban development and geophysics

NASA Astrophysics Data System (ADS)

Liu, Lanbo; Chan, L. S.

2007-09-01

The new millennium has seen a fresh wave of world economic development especially in the Asian-Pacific region. This has contributed to further rapid urban expansion, creating shortages of energy and resources, degradation of the environment, and changes to climatic patterns. Large-scale, new urbanization is mostly seen in developing countries but urban sprawl is also a major social problem for developed nations. Urbanization has been accelerating at a tremendous rate. According to data collected by the United Nations [1], 50 years ago less than 30% of the world population lived in cities. Now, more than 50% are living in urban settings which occupy only about 1% of the Earth's surface. During the period from 1950 to 1995, the number of cities with a population higher than one million increased from 83 to 325. By 2025 it is estimated that more than 60% of 8.3 billion people (the projected world population [1]) will be city dwellers. Urbanization and urban sprawl can affect our living quality both positively and negatively. In recent years geophysics has found significant and new applications in highly urbanized settings. Such applications are conducive to the understanding of the changes and impacts on the physical environment and play a role in developing sustainable urban infrastructure systems. We would like to refer to this field of study as 'urban geophysics'. Urban geophysics is not simply the application of geophysical exploration in the cities. Urbanization has brought about major changes to the geophysical fields of cities, including those associated with electricity, magnetism, electromagnetism and heat. An example is the increased use of electromagnetic waves in wireless communication, transportation, office automation, and computer equipment. How such an increased intensity of electromagnetic radiation affects the behaviour of charged particles in the atmosphere, the equilibrium of ecological systems, or human health, are new research frontiers to be investigated [2]. The first objective of urban geophysics is to study systematically the geophysical fields in cities, searching for principles and processes governing the intensity and patterns of variation of the geophysical properties, as well as the potential consequences on the biosphere. Secondly, geophysics has already been found to be a useful tool for subsurface detection and investigation, hazard mitigation, and assessment of environmental contamination. Geophysicists have documented numerous cases of successful applications of geophysical techniques to solve problems related to hazard mitigation, safeguarding of lifeline infrastructure and urban gateways (air- and sea-ports, railway and highway terminals), archaeological and heritage surveys, homeland security, urban noise control, water supplies, sanitation and solid waste management etc. In contrast to conventional geophysical exploration, the undertaking of geophysical surveys in an urban setting faces many new challenges and difficulties. First of all, the ambient cultural noise in cities caused by traffic, electromagnetic radiation and electrical currents often produce undesirably strong interference with geophysical measurements. Secondly, subsurface surveys in an urban area are often targeted at the uppermost several metres of the ground, which are the most heterogeneous layers with many man-made objects. Thirdly, unlike conventional geophysical exploration which requires resolution in the order of metres, many urban geophysical surveys demand a resolution and precision in the order of centimetres or even millimetres. Finally restricted site access and limited time for conducting geophysical surveys, regulatory constraints, requirements for traffic management and special logistical arrangements impose additional difficulties. All of these factors point to the need for developing innovative research methods and geophysical instruments suitable for use in urban settings. This special issue on 'Sustainable urban development and geophysics' in Journal of Geophysics and Engineering is a response to the call for the development of novel geophysical techniques especially applicable to city settings. It consists of 11 papers which are selected and expanded from a collection of papers presented to the special sessions on 'Sustainable Urban Development and Geophysics' (U14A, U15A, and U41B) in the Union section of the Western Pacific Geophysics Meeting held in Beijing, China, on 22-27 July 2006 [3]. This indicates that new and innovative geophysical applications in urban settings have emerged, and these innovations may be potentially useful for the planning, implementation, and maintenance of urban infrastructure systems. These 11 research papers can be divided into three groups: (1) geophysics and urban infrastructure; (2) geophysics and urban environment; and (3) geophysical investigations associated with geological hazards. The first group of papers focuses on urban infrastructure. Fred Stumm et al reported a geohydrologic assessment of fractured crystalline bedrock with borehole radar in Manhattan, New York in preparation for the construction of a new water tunnel. Using GPR, Xie et al conducted a quality control study of the walls of the river-crossing highway tunnel in Shanghai. For the same purpose, S Liu et al investigated the effect of concrete cracks on GPR signatures using a numerical simulation technique. Sun et al, using seismic surface waves, investigated road beds and the degree of weathering of the marble fence in the Forbidden City, Beijing. In the second group of papers, using a numerical simulation technique, L Liu et al studied the effect of a building coordinate error on sound wave propagation with the aim of locating sound sources in urban settings. Chan et al studied the abundance of radio elements in weathered igneous bedrock in Hong Kong for the purpose of the promotion of public health in the urban environment. The third group includes five papers on geo-hazards. The three papers by B Zhao et al and Z Zhao et al address the problem of earthquake strong ground motion in urban regions using case studies from Osaka, Japan and the city of Yinchuan, China. The other two papers study the geological hazard of surface subsidence using geophysical tools: G Leucci reported a comprehensive study in Nardo, Italy, while Kim et al reported a similar case study for a small city in South Korea. One striking feature of all the papers in this special issue is that multiple authors with at least 3 co-authors wrote the majority of the papers, which is an indication of strong team work and interdisciplinary collaboration. This is essential for the successful application of geophysical science and technology in tackling a variety of engineering and environmental problems for the urban setting. The only sole author, Dr Leucci, expressed deep gratitude in his acknowledgements to his team members who carried out substantial parts of the data acquisition. We are pleased to present this special issue to the engineering and environmental geophysics community and hope that it can serve as a snapshot of the current state-of-the-art studies in urban geophysics. References [1] United Nations 1990 World Demographic Estimates and Projections (1950-2025) (New York: Press of United Nations) [2] Chen Y, L-S Chan and S Yu 2003 J. Geodesy & Geodynamics 23 1-4 (in Chinese) [3] American Geophysics Union 2006 Eos Trans. AGU 87 (36)

The Importance of Mars Samples in Constraining the Geological and Geophysical Processes on Mars and the Nature of its Crust, Mantle, and Core

NASA Astrophysics Data System (ADS)

iMOST Team; Herd, C. D. K.; Ammannito, E.; Anand, M.; Debaille, V.; Hallis, L. J.; McCubbin, F. M.; Schmitz, N.; Usui, T.; Weiss, B. P.; Altieri, F.; Amelin, Y.; Beaty, D. W.; Benning, L. G.; Bishop, J. L.; Borg, L. E.; Boucher, D.; Brucato, J. R.; Busemann, H.; Campbell, K. A.; Carrier, B. L.; Czaja, A. D.; Des Marais, D. J.; Dixon, M.; Ehlmann, B. L.; Farmer, J. D.; Fernandez-Remolar, D. C.; Fogarty, J.; Glavin, D. P.; Goreva, Y. S.; Grady, M. M.; Harrington, A. D.; Hausrath, E. M.; Horgan, B.; Humayun, M.; Kleine, T.; Kleinhenz, J.; Mangold, N.; Mackelprang, R.; Mayhew, L. E.; McCoy, J. T.; McLennan, S. M.; McSween, H. Y.; Moser, D. E.; Moynier, F.; Mustard, J. F.; Niles, P. B.; Ori, G. G.; Raulin, F.; Rettberg, P.; Rucker, M. A.; Sefton-Nash, E.; Sephton, M. A.; Shaheen, R.; Shuster, D. L.; Siljestrom, S.; Smith, C. L.; Spry, J. A.; Steele, A.; Swindle, T. D.; ten Kate, I. L.; Tosca, N. J.; Van Kranendonk, M. J.; Wadhwa, M.; Werner, S. C.; Westall, F.; Wheeler, R. M.; Zipfel, J.; Zorzano, M. P.

2018-04-01

We present the main sample types from any potential Mars Sample Return landing site that would be required to constrain the geological and geophysical processes on Mars, including the origin and nature of its crust, mantle, and core.

76 FR 65521 - Information Collection; Geological and Geophysical Explorations of the Outer Continental Shelf...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-21

... submitted. Permittees are to be reimbursed also for the reasonable cost of processing geophysical information required to be submitted when processing is in a form or manner required by the Director, BOEM... G&G exploration, including deep stratigraphic tests/ revisions when necessary. 74 applications x $2...

The study of the midlatitude ionospheric response to geomagnetic activity at Nagycenk Geophysical Observatory

NASA Astrophysics Data System (ADS)

Berényi, Kitti; Kis, Árpád; Barta, Veronika; Novák, Attila

2016-04-01

Geomagnetic storms affect the ionospheric regions of the terrestrial upper atmosphere, causing several physical and chemical atmospheric processes. The changes and phenomena, which can be seen as a result of these processes, generally called ionospheric storm. These processes depend on altitude, term of the day, and the strength of solar activity, the geomagnetic latitude and longitude. The differences between ionospheric regions mostly come from the variations of altitude dependent neutral and ionized atmospheric components, and from the physical parameters of solar radiation. We examined the data of the ground-based radio wave ionosphere sounding instruments of the European ionospheric stations (mainly the data of Nagycenk Geophysical Observatory), called ionosonde, to determine how and what extent a given strength of a geomagnetic disturbance affect the middle latitude ionospheric regions in winter. We chose the storm for the research from November 2012 and March 2015. As the main result of our research, we can show significant differences between the each ionospheric (F1 and F2) layer parameters on quiet and strong stormy days. When we saw, that the critical frequencies (foF2) increase from their quiet day value, then the effect of the ionospheric storm was positive, otherwise, if they drop, they were negative. With our analysis, the magnitude of these changes could be determined. Furthermore we demonstrated, how a full strong geomagnetic storm affects the ionospheric foF2 parameter during different storm phases. It has been showed, how a positive or negative ionospheric storm develop during a geomagnetic storm. For a more completed analysis, we compared also the evolution of the F2 layer parameters of the European ionosonde stations on a North-South geographic longitude during a full storm duration. Therefore we determined, that the data of the ionosonde at Nagycenk Geophysical Observatory are appropriate, it detects the same state of ionosphere like the European ionosondes. Also we studied the prominent phenomena (e.g. TIDs- Travelling Ionospheric Disturbances), and plasma irregularities (e.g. spread-F) of the ionosphere in the function of geomagnetic activity. As we compared the occurrences of TIDs and spread-F phenomena on the quiet days with their occurrences on moderate and strong stormy days, we can see significant correlation between the magnitude of the Ae-index and the daily number of the occurrence of TIDs, but at the same time there is no definite connection between the daily number of the occurrence of spread-F phenomenas and the intensity of geomagnetic activity.

The role of the geophysical template and environmental regimes in controlling stream-living trout populations

Treesearch

Brooke E. Penaluna; Steve F. Railsback; Jason B. Dunham; Sherri Johnson; Robert E. Bilby; Arne E. Skaugset; Michael Bradford

2015-01-01

The importance of multiple processes and instream factors to aquatic biota has been explored extensively, but questions remain about how local spatiotemporal variability of aquatic biota is tied to environmental regimes and the geophysical template of streams. We used an individual-based trout model to explore the relative role of the geophysical template versus...

Hydrologic Process-oriented Optimization of Electrical Resistivity Tomography

NASA Astrophysics Data System (ADS)

Hinnell, A.; Bechtold, M.; Ferre, T. A.; van der Kruk, J.

2010-12-01

Electrical resistivity tomography (ERT) is commonly used in hydrologic investigations. Advances in joint and coupled hydrogeophysical inversion have enhanced the quantitative use of ERT to construct and condition hydrologic models (i.e. identify hydrologic structure and estimate hydrologic parameters). However the selection of which electrical resistivity data to collect and use is often determined by a combination of data requirements for geophysical analysis, intuition on the part of the hydrogeophysicist and logistical constraints of the laboratory or field site. One of the advantages of coupled hydrogeophysical inversion is the direct link between the hydrologic model and the individual geophysical data used to condition the model. That is, there is no requirement to collect geophysical data suitable for independent geophysical inversion. The geophysical measurements collected can be optimized for estimation of hydrologic model parameters rather than to develop a geophysical model. Using a synthetic model of drip irrigation we evaluate the value of individual resistivity measurements to describe the soil hydraulic properties and then use this information to build a data set optimized for characterizing hydrologic processes. We then compare the information content in the optimized data set with the information content in a data set optimized using a Jacobian sensitivity analysis.

Geological-geophysical techniques applied to urban planning in karst hazardous areas. Case study of Zaragoza, NE Spain

NASA Astrophysics Data System (ADS)

Pueyo Anchuela, O.; Soriano, A.; Casas Sainz, A.; Pocoví Juan, A.

2009-12-01

Industrial and urban growth must deal in some settings with geological hazards. In the last 50 years, the city of Zaragoza (NE Spain) has developed an increase of its urbanized area in a progression several orders higher than expected from its population increase. This fast growth has affected several areas around the city that were not usually used for construction. Maps of the Zaragoza city area at the end of the XIXth century and beginning of the XXth reveal the presence of karst hazards in several zones that can be observed in more modern data, as aerial photographs taken during a period ranging from 1927 to present. The urban and industrial development has covered many of these hazardous zones, even though potential risks were known. The origins of the karst problems are related to the solution of evaporites (mainly gypsum, glauberite and halite) that represent the Miocene substratum of the Zaragoza area underlying the Quaternary terraces and pediments related to the Ebro River and its tributaries. Historical data show the persistence of subsidence foci during long periods of time while in recent urbanized areas this stability is not shared, observing the increase of activity and/or radius affection in short periods of time after building over. These problems can be related to two factors: i) urban development over hazardous areas can increase the karst activity and ii) the affection radius is not properly established with the commonly applied methods. One way to develop these detailed maps can be related to the geophysical approach. The applied geophysical routine, dependent on the characteristics of the surveyed area, is based on potential geophysical techniques (magnetometry and gravimetry) and others related to the application of induced fields (EM and GPR). The obtained results can be related to more straightforward criteria as the detection of cavities in the subsoil and indirect indicators related to the long-term activity of the subsidence areas (changes in the filling of the subsidence area, changes in the position of the substratum or processes inferred from geometrical changes from the surveyed materials). In open field, techniques as magnetometry and EM radiation can be a very fast survey methodology and GPR and microgravimetry can be applied to inhomogeneous identified zones. In urban settings GPR must be applied first, followed by gravimetry in the inhomogeneous zones. Some hazardous areas can be unnoticed from the sole application of aerial photography or historical cartographies whereas when used together with multidisciplinar geophysical surveys, they can be sensitive to the different karst hazards features. The presented routine can permit the urban planning development at regional and local scale or the engineering and architectural building development at more local scale.

The detection of gravitational waves using electrodynamic system of Earth

NASA Astrophysics Data System (ADS)

Grunskaya, Lubov; Isakevich, Valiriy

There is studied the interconnection of tide processes of geophysical and astrophysical origin with the Earth electromagnetic fields. There has been developed a programme-analytical system (PAS) to investigate signal structures in spectral and time series, caused by geophysical and astrophysical processes based on the method of eigen vectors. There were discovered frequencies in the electrical and geomagnetical field of ELF range with PAS, which coincide with the frequency of gravitational -wave radiation of a number of double stellar systems. In the electrical and geomagnetic field there was discovered a specific axion frequency VA=0.5*10-5 Hz belonging to the ELF range which was predicted by the theory. The problem of the anomalous behavior of the electrodynamic system response to the gravitational - wave affect is being discussed. On the basis of the rich experimental material have been investigated the frequencies of gravitational-wave radiation of a number of binary systems: J0700+6418, J1012+5307, J1537+1155, J1959+2048, J2130+1210, J1915+1606. The work is carried out with supporting of RFFI No. 14-07-97510, State Task to Universities on 2014-2016.

Mobile geophysics for searching and exploration of Domanic hydrocarbon deposits

NASA Astrophysics Data System (ADS)

Borovsky, M. Ya; Uspensky, B. V.; Valeeva, S. E.; Borisov, A. S.

2018-05-01

There are noted features of shale hydrocarbons occurrence. It is shown the role of geophysical prospecting in the geological prospecting process for non-traditional sources of hydrocarbon. There are considered the possibilities of non-seismic methods for forecasting, prospecting, exploration and preparation of Domanikovian hydrocarbons accumulations for exploration. It is emphasized the need for geophysical studies of tectonic disturbances. Modern aerogeophysical instrumentation and methodological support allows to combine high-precision magneto-prospecting with gravimetric and gamma spectrometry. This combination of geophysical methods contributes to the diagnosis of active and latent faults.

Review of current GPS methodologies for producing accurate time series and their error sources

NASA Astrophysics Data System (ADS)

He, Xiaoxing; Montillet, Jean-Philippe; Fernandes, Rui; Bos, Machiel; Yu, Kegen; Hua, Xianghong; Jiang, Weiping

2017-05-01

The Global Positioning System (GPS) is an important tool to observe and model geodynamic processes such as plate tectonics and post-glacial rebound. In the last three decades, GPS has seen tremendous advances in the precision of the measurements, which allow researchers to study geophysical signals through a careful analysis of daily time series of GPS receiver coordinates. However, the GPS observations contain errors and the time series can be described as the sum of a real signal and noise. The signal itself can again be divided into station displacements due to geophysical causes and to disturbing factors. Examples of the latter are errors in the realization and stability of the reference frame and corrections due to ionospheric and tropospheric delays and GPS satellite orbit errors. There is an increasing demand on detecting millimeter to sub-millimeter level ground displacement signals in order to further understand regional scale geodetic phenomena hence requiring further improvements in the sensitivity of the GPS solutions. This paper provides a review spanning over 25 years of advances in processing strategies, error mitigation methods and noise modeling for the processing and analysis of GPS daily position time series. The processing of the observations is described step-by-step and mainly with three different strategies in order to explain the weaknesses and strengths of the existing methodologies. In particular, we focus on the choice of the stochastic model in the GPS time series, which directly affects the estimation of the functional model including, for example, tectonic rates, seasonal signals and co-seismic offsets. Moreover, the geodetic community continues to develop computational methods to fully automatize all phases from analysis of GPS time series. This idea is greatly motivated by the large number of GPS receivers installed around the world for diverse applications ranging from surveying small deformations of civil engineering structures (e.g., subsidence of the highway bridge) to the detection of particular geophysical signals.

Basic exploration geophysics

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

Robinson, E.S.

1988-01-01

An introduction to geophysical methods used to explore for natural resources and to survey earth's geology is presented in this volume. It is suitable for second-and third-year undergraduate students majoring in geology or engineering and for professional engineering and for professional engineers and earth scientists without formal instruction in geophysics. The author assumes the reader is familiar with geometry, algebra, and trigonometry. Geophysical exploration includes seismic refraction and reflection surveying, electrical resistivity and electromagnetic field surveying, and geophysical well logging. Surveying operations are described in step-by-step procedures and are illustrated by practical examples. Computer-based methods of processing and interpreting datamore » as well as geographical methods are introduced.« less

Geophysical assessment of karst activity

DOT National Transportation Integrated Search

2008-02-01

MST proposes to acquire electrical resistivity data within a pipeline/roadway ROW. These geophysical data will be processed, analyzed and interpreted with the objective of locating and mapping any subsurface voids that might compromise the integrity ...

Investigations into near-real-time surveying for geophysical data collection using an autonomous ground vehicle

USGS Publications Warehouse

Phelps, Geoffrey A.; Ippolito, C.; Lee, R.; Spritzer, R.; Yeh, Y.

2014-01-01

The U.S. Geological Survey and the National Aeronautics and Space Administration are cooperatively investigating the utility of unmanned vehicles for near-real-time autonomous surveys of geophysical data collection. Initially focused on unmanned ground vehicle collection of magnetic data, this cooperative effort has brought unmanned surveying, precision guidance, near-real-time communication, on-the-fly data processing, and near-real-time data interpretation into the realm of ground geophysical surveying, all of which offer advantages over current methods of manned collection of ground magnetic data. An unmanned ground vehicle mission has demonstrated that these vehicles can successfully complete missions to collect geophysical data, and add advantages in data collection, processing, and interpretation. We view the current experiment as an initial phase in further unmanned vehicle data-collection missions, including aerial surveying.

Atmosphere-Ice-Ocean-Ecosystem Processes in a Thinner Arctic Sea Ice Regime: The Norwegian Young Sea ICE (N-ICE2015) Expedition

NASA Astrophysics Data System (ADS)

Granskog, Mats A.; Fer, Ilker; Rinke, Annette; Steen, Harald

2018-03-01

Arctic sea ice has been in rapid decline the last decade and the Norwegian young sea ICE (N-ICE2015) expedition sought to investigate key processes in a thin Arctic sea ice regime, with emphasis on atmosphere-snow-ice-ocean dynamics and sea ice associated ecosystem. The main findings from a half-year long campaign are collected into this special section spanning the Journal of Geophysical Research: Atmospheres, Journal of Geophysical Research: Oceans, and Journal of Geophysical Research: Biogeosciences and provide a basis for a better understanding of processes in a thin sea ice regime in the high Arctic. All data from the campaign are made freely available to the research community.

A method of hidden Markov model optimization for use with geophysical data sets

NASA Technical Reports Server (NTRS)

Granat, R. A.

2003-01-01

Geophysics research has been faced with a growing need for automated techniques with which to process large quantities of data. A successful tool must meet a number of requirements: it should be consistent, require minimal parameter tuning, and produce scientifically meaningful results in reasonable time. We introduce a hidden Markov model (HMM)-based method for analysis of geophysical data sets that attempts to address these issues.

A conceptual model for the asthenosphere: redox melting in the C-O-H-bearing mantle vs. geophysical observations

NASA Astrophysics Data System (ADS)

Gaillard, Fabrice; Tarits, Pascal; Massuyeau, Malcolm; David, Sifre; Leila, Hashim; Emmanuel, Gardes

2013-04-01

The asthenosphere has classically been considered as a convective layer, with its viscosity decreased by the presence of 100's ppm water in olivine, and being overtopped by a rigid and dry lithosphere. It, however, needs a new conceptual definition as the presence of water seems not able to affect the rheology of olivine; furthermore, properties such as electrical conductivity and seismic wave's velocity are not sensibly affected by water content in olivine, leaving the geophysical features of the asthenosphere unexplained. An asthenosphere impregnated by low melt fractions is consistent with constraints on melting behavior of C-O-H-bearing peridotites and may also better explain electrical conductivity and seismic features. The challenge is therefore to confront and reconcile the complexity of mantle melting in the C-O-H system with geophysical observations. This work reviews and discusses several key properties of the asthenosphere and relates their vertical and lateral heterogeneities to geodynamic processes. The first discussion is about the top of the Lithosphere-Asthenosphere boundary in the oceanic mantle. The discontinuity identified by seismic and electrical surveys is located at an average depth of 65km and is weakly influenced by the age, and therefore, the temperature of the lithosphere. This puzzling observation is shown here to be in perfect line the onset of peridotite melting in presence of both H2O and CO2. Mantle melting is therefore expected at 65 km depth, where the melt is essentially carbonatitic, inducing weakening and imposing transition in the regime of thermal transfer. Deeper, the melt evolve to silica-richer compositions. Twenty years of petrological investigations on processes that control mantle redox state unanimously concur on an increasingly reduced mantle with increasing depth. The conventional wisdom defines garnet as being increasingly abundant and increasingly able to concentrate ferric iron with increasing depth. Such oxygen pump results in an increasingly reduced mantle with depth. Recent surveys have calibrated the carbon-carbonate redox transition at mantle pressure and have located its depth around 180-250 km (depth of redox melting); Deeper, only diamond is stable; Shallower, carbonates, mostly in its molten state, are expected. This petrological model is confronted to the most recent geophysical observations. Such observations indicate that melting must occur at depth down to 400 km, which conflict with the concept of redox melting. What is the composition of the melt? Hydrous silicate melt or hydrous carbonated melt? What does it mean in terms of deep upper mantle redox state?

Preface: Current perspectives in modelling, monitoring, and predicting geophysical fluid dynamics

NASA Astrophysics Data System (ADS)

Mancho, Ana M.; Hernández-García, Emilio; López, Cristóbal; Turiel, Antonio; Wiggins, Stephen; Pérez-Muñuzuri, Vicente

2018-02-01

The third edition of the international workshop Nonlinear Processes in Oceanic and Atmospheric Flows was held at the Institute of Mathematical Sciences (ICMAT) in Madrid from 6 to 8 July 2016. The event gathered oceanographers, atmospheric scientists, physicists, and applied mathematicians sharing a common interest in the nonlinear dynamics of geophysical fluid flows. The philosophy of this meeting was to bring together researchers from a variety of backgrounds into an environment that favoured a vigorous discussion of concepts across different disciplines. The present Special Issue on Current perspectives in modelling, monitoring, and predicting geophysical fluid dynamics contains selected contributions, mainly from attendants of the workshop, providing an updated perspective on modelling aspects of geophysical flows as well as issues on prediction and assimilation of observational data and novel tools for describing transport and mixing processes in these contexts. More details on these aspects are discussed in this preface.

Prospect of Continuous VLBI Measurement of Earth Rotation in Monitoring Geophysical Fluids

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Ma, Chopo; Clark, Thomas

1998-01-01

Large-scale mass transports in the geophysical fluids of the Earth system excite Earth's rotational variations in both length-of-day and polar motion. The excitation process is via the conservation of angular momentum. Therefore Earth rotation observations contain information about the integrated angular momentum (consisting of both the mass term and the motion term) of the geophysical fluids, which include atmosphere, hydrosphere, mantle, and the outer and inner cores. Such global information is often important and otherwise unattainable depending on the nature of the mass transport, its magnitude and time scale. The last few years have seen great advances in VLBI measurement of Earth rotation in precision and temporal resolution. These advances have opened new. areas in geophysical fluid studies, such as oceanic tidal angular momentum, atmospheric tides, Earth librations, and rapid atmospheric angular momentum fluctuations. Precision of 10 microseconds in UTI and 200 microarcseconds in polar motion can now be achieved on hourly basis. Building upon this heritage, the multi-network geodetic VLBI project, Continuous Observation of the Rotation of the Earth (CORE), promises to further these studies and to make possible studies on elusive but tell-tale geophysical processes such as oscillatory modes in the core and in the atmosphere. Currently the early phase of CORE is underway. Within a few years into the new mellinnium, the upcoming space gravity missions (such as GRACE) will measure the temporal variations in Earth's gravitational field, thus providing complementary information to that from Earth rotation study for a better understanding of global geophysical fluid processes.

Recent uplift of the Atlantic Atlas (offshore West Morocco): Tectonic arch and submarine terraces

NASA Astrophysics Data System (ADS)

Benabdellouahed, M.; Klingelhoefer, F.; Gutscher, M.-A.; Rabineau, M.; Biari, Y.; Hafid, M.; Duarte, J. C.; Schnabel, M.; Baltzer, A.; Pedoja, K.; Le Roy, P.; Reichert, C.; Sahabi, M.

2017-06-01

Re-examination of marine geophysical data from the continental margin of West Morocco reveals a broad zone characterized by deformation, active faults and updoming offshore the High Atlas (Morocco margin), situated next to the Tafelney Plateau. Both seismic reflection and swath-bathymetric data, acquired during Mirror marine geophysical survey in 2011, indicate recent uplift of the margin including uplift of the basement. This deformation, which we propose to name the Atlantic Atlas tectonic arch, is interpreted to result largely through uplift of the basement, which originated during the Central Atlantic rifting stage - or even during phases of Hercynian deformation. This has produced a large number of closely spaced normal and reverse faults, ;piano key faults;, originating from the basement and affecting the entire sedimentary sequence, as well as the seafloor. The presence of four terraces in the Essaouira canyon system at about 3500 meters water depth and ;piano key faults; and the fact that these also affect the seafloor, indicate that the Atlantic Atlas is still active north of Agadir canyon. We propose that recent uplift is causing morphogenesis of four terraces in the Essaouira canyon system. In this paper the role of both Canary plume migration and ongoing convergence between the African and Eurasian plates in the formation of the Atlantic Atlas are discussed as possibilities to explain the presence of a tectonic arch in the region. The process of reactivation of passive margins is still not well understood. The region north of Agadir canyon represents a key area to better understand this process.

Updating the Framework Geology of Padre Island National Seashore: Validation of Geophysical Surveys through Sediment Cores

NASA Astrophysics Data System (ADS)

Tuttle, L. F., II; Wernette, P. A.; Houser, C.

2016-12-01

Framework geology has been demonstrated to influence the geomorphology and affect the response of barrier islands to extreme storm events. Therefore, it is vital that we understand the framework geology before we can accurately assess the vulnerability and resiliency of the coast. Geophysical surveys consisting of ground-penetrating radar (GPR) and electromagnetic inductance (EMI) were collected along the length of Padre Island National Seashore (PAIS) to map subsurface infilled paleochannels identified in previous research. The most extensive published survey of PAIS framework geology was conducted in the 1950s as part of dredging the Intracoastal Waterway through Laguna Madre. Using cores and seismic surveys the previous study identified a series of relict infilled paleochannels in dissecting PAIS. The sediment cores presented in our poster were collected in Fall 2016 with a Geoprobe 6712DT. Cores were stored and processed using an X-ray fluorescence (XRF) scanner at the International Ocean Discovery Program repository in College Station, Texas. The XRF data was used to examine mineralogical differences that provide valuable insight into the evolutionary history of the island. This poster presents results from sediment cores collected to validate the geophysical survey data. The broader purpose of this research is to validate the subsurface framework geology features (i.e. infilled paleochannels) in order to more accurately predict future changes to the environmental and economic longevity of PAIS.

Groundwater flow pattern and related environmental phenomena in complex geologic setting based on integrated model construction

NASA Astrophysics Data System (ADS)

Tóth, Ádám; Havril, Tímea; Simon, Szilvia; Galsa, Attila; Monteiro Santos, Fernando A.; Müller, Imre; Mádl-Szőnyi, Judit

2016-08-01

Groundwater flow, driven, controlled and determined by topography, geology and climate, is responsible for several natural surface manifestations and affected by anthropogenic processes. Therefore, flowing groundwater can be regarded as an environmental agent. Numerical simulation of groundwater flow could reveal the flow pattern and explain the observed features. In complex geologic framework, where the geologic-hydrogeologic knowledge is limited, the groundwater flow model could not be constructed based solely on borehole data, but geophysical information could aid the model building. The integrated model construction was presented via the case study of the Tihany Peninsula, Hungary, with the aims of understanding the background and occurrence of groundwater-related environmental phenomena, such as wetlands, surface water-groundwater interaction, slope instability, and revealing the potential effect of anthropogenic activity and climate change. The hydrogeologic model was prepared on the basis of the compiled archive geophysical database and the results of recently performed geophysical measurements complemented with geologic-hydrogeologic data. Derivation of different electrostratigraphic units, revealing fracturing and detecting tectonic elements was achieved by systematically combined electromagnetic geophysical methods. The deduced information can be used as model input for groundwater flow simulation concerning hydrostratigraphy, geometry and boundary conditions. The results of numerical modelling were interpreted on the basis of gravity-driven regional groundwater flow concept and validated by field mapping of groundwater-related phenomena. The 3D model clarified the hydraulic behaviour of the formations, revealed the subsurface hydraulic connection between groundwater and wetlands and displayed the groundwater discharge pattern, as well. The position of wetlands, their vegetation type, discharge features and induced landslides were explained as environmental imprints of groundwater. The highly vulnerable wetlands and groundwater-dependent ecosystems have to be in the focus of water management and natural conservation policy.

Fractional properties of geophysical field variability on the example of hydrochemical parameters

NASA Astrophysics Data System (ADS)

Shevtsov, Boris; Shevtsova, Olga

2017-10-01

Using the properties of compound Poisson process and its fractional generalizations, statistical models of geophysical fields variability are considered on an example of hydrochemical parameters system. These models are universal to describe objects of different nature and allow us to explain various pulsing regime. Manifestations of non-conservatism in hydrochemical parameters system and the advantages of the system approach in the description of geophysical fields variability are discussed.

Parameters on reconstructions of geohistory, thermal history, and hydrocarbon generation history in a sedimentary basin

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

Cao, S.; Lerche, I.

1988-01-01

Geological processes related to petroleum generation, migration, and accumulation are very complicated in terms of time and variables involved, and are very difficult to simulate by laboratory experiments. For this reason, many mathematic/computer models have been developed to simulate these geological processes based on geological, geophysical, and geochemical principles. Unfortunately, none of these models can exactly simulate these processes because of the assumptions and simplifications made in these models and the errors in the input for the models. The sensitivity analysis is a comprehensive examination on how geological, geophysical, and geochemical parameters affect the reconstructions of geohistory, thermal history, andmore » hydrocarbon generation history. In this study, a one-dimensional fluid flow/compaction model has been used to run the sensitivity analysis. The authors will show the effects of some commonly used parameters such as depth, age, lithology, porosity, permeability, unconformity (time and eroded thickness), temperature at sediment surface, bottom hole temperature, present day heat flow, thermal gradient, thermal conductivity and kerogen type, and content on the evolutions of formation thickness, porosity, permeability, pressure with time and depth, heat flow with time, temperature with time and depth, vitrinite reflectance (R/sub 0/) and TTI with time and depth, oil window in terms of time and depth, and amount of hydrocarbon generated with time and depth.« less

Understanding and Forecasting Upper Atmosphere Nitric Oxide Through Data Mining Analysis of TIMED/SABER Data

NASA Astrophysics Data System (ADS)

Flynn, S.; Knipp, D. J.; Matsuo, T.; Mlynczak, M. G.; Hunt, L. A.

2017-12-01

Storm time energy input to the upper atmosphere is countered by infrared radiative emissions from nitric oxide (NO). The temporal profile of these energy sources and losses strongly control thermospheric density profiles, which in turn affect the drag experienced by low Earth orbiting satellites. Storm time processes create NO. In some extreme cases an overabundance of NO emissions unexpectedly decreases atmospheric temperature and density to lower than pre-storm values. Quantifying the spatial and temporal variability of the NO emissions using eigenmodes will increase the understanding of how upper atmospheric NO behaves, and could be used to increase the accuracy of future space weather and climate models. Thirteen years of NO flux data, observed at 100-250 km altitude by the SABER instrument onboard the TIMED satellite, is decomposed into five empirical orthogonal functions (EOFs) and their amplitudes to: 1) determine the strongest modes of variability in the data set, and 2) develop a compact model of NO flux. The first five EOFs account for 85% of the variability in the data, and their uncertainty is verified using cross-validation analysis. Although these linearly independent EOFs are not necessarily independent in a geophysical sense, the first three EOFs correlate strongly with different geophysical processes. The first EOF correlates strongly with Kp and F10.7, suggesting that geomagnetic storms and solar weather account for a large portion of NO flux variability. EOF 2 shows annual variations, and EOF 3 correlates with solar wind parameters. Using these relations, an empirical model of the EOF amplitudes can be derived, which could be used as a predictive tool for future NO emissions. We illustrate the NO model, highlight some of the hemispheric asymmetries, and discuss the geophysical associations of the EOFs.

A connectionist-geostatistical approach for classification of deformation types in ice surfaces

NASA Astrophysics Data System (ADS)

Goetz-Weiss, L. R.; Herzfeld, U. C.; Hale, R. G.; Hunke, E. C.; Bobeck, J.

2014-12-01

Deformation is a class of highly non-linear geophysical processes from which one can infer other geophysical variables in a dynamical system. For example, in an ice-dynamic model, deformation is related to velocity, basal sliding, surface elevation changes, and the stress field at the surface as well as internal to a glacier. While many of these variables cannot be observed, deformation state can be an observable variable, because deformation in glaciers (once a viscosity threshold is exceeded) manifests itself in crevasses.Given the amount of information that can be inferred from observing surface deformation, an automated method for classifying surface imagery becomes increasingly desirable. In this paper a Neural Network is used to recognize classes of crevasse types over the Bering Bagley Glacier System (BBGS) during a surge (2011-2013-?). A surge is a spatially and temporally highly variable and rapid acceleration of the glacier. Therefore, many different crevasse types occur in a short time frame and in close proximity, and these crevasse fields hold information on the geophysical processes of the surge.The connectionist-geostatistical approach uses directional experimental (discrete) variograms to parameterize images into a form that the Neural Network can recognize. Recognizing that each surge wave results in different crevasse types and that environmental conditions affect the appearance in imagery, we have developed a semi-automated pre-training software to adapt the Neural Net to chaining conditions.The method is applied to airborne and satellite imagery to classify surge crevasses from the BBGS surge. This method works well for classifying spatially repetitive images such as the crevasses over Bering Glacier. We expand the network for less repetitive images in order to analyze imagery collected over the Arctic sea ice, to assess the percentage of deformed ice for model calibration.

Fulbright update

NASA Astrophysics Data System (ADS)

Opportunities to teach or perform postdoctoral research in the earth and atmospheric sciences under the Senior Scholar Fulbright awards program for 1984-1985 (Eos, March 1, 1983, p. 81) are available in 14 countries, according to the Council for International Exchange of Scholars.The countries and the specialization opportunities are Algeria, any specialization; Australia, mineral processing research; India, any specialization in geology or geophysics; Israel, environmental studies; Korea, any specialization; Lebanon, geophysics, geotectonics, and structural geology; Morocco, research methods in science education; Pakistan, geology, marine biology, and mineralogy; Poland, mining technology; Sudan, geology and remote sensing; Thailand, planning and environmental change; USSR, any specialization; Yugoslavia, any research specialization; and Zimbabwe, exploration geophysics and solid earth geophysics.

Space weather monitoring by ground-based means carried out in Polar Geophysical Center at Arctic and Antarctic Research Institute

NASA Astrophysics Data System (ADS)

Janzhura, Alexander

A real-time information on geophysical processes in polar regions is very important for goals of Space Weather monitoring by the ground-based means. The modern communication systems and computer technology makes it possible to collect and process the data from remote sites without significant delays. A new acquisition equipment based on microprocessor modules and reliable in hush climatic conditions was deployed at the Roshydromet networks of geophysical observations in Arctic and is deployed at observatories in Antarctic. A contemporary system for on-line collecting and transmitting the geophysical data from the Arctic and Antarctic stations to AARI has been realized and the Polar Geophysical Center (PGC) arranged at AARI ensures the near-real time processing and analyzing the geophysical information from 11 stations in Arctic and 5 stations in Antarctic. The space weather monitoring by the ground based means is one of the main tasks standing before the Polar Geophysical Center. As studies by Troshichev and Janzhura, [2012] showed, the PC index characterizing the polar cap magnetic activity appeared to be an adequate indicator of the solar wind energy that entered into the magnetosphere and the energy that is accumulating in the magnetosphere. A great advantage of the PC index application over other methods based on satellite data is a permanent on-line availability of information about magnetic activity in both northern and southern polar caps. A special procedure agreed between Arctic and Antarctic Research Institute (AARI) and Space Institute of the Danish Technical University (DTUSpace) ensures calculation of the unified PC index in quasi-real time by magnetic data from the Thule and Vostok stations (see public site: http://pc-index.org). The method for estimation of AL and Dst indices (as indicators of state of the disturbed magnetosphere) based on data on foregoing PC indices has been elaborated and testified in the Polar Geophysical Center. It is demonstrated that the PC index can be successfully used to monitor the state of the magnetosphere (space weather monitoring) and the readiness of the magnetosphere to producing substorm or storm (space weather nowcasting).

Aquifers as indicators of volcanic unrest - models of hydrological responses to magmatic activity and their geophysical signals

NASA Astrophysics Data System (ADS)

Strehlow, Karen; Gottsmann, Jo

2014-05-01

Aquifers respond to and modify the surface expressions of magmatic activity, and they can also become agents of unrest themselves. Therefore, monitoring the hydrology can provide a valuable window into subsurface processes in volcanic areas. Interpretations of unrest signals as groundwater responses to changes in the magmatic system can be found for many volcanoes. Changes in temperature and strain conditions, seismic excitation or the injection of magmatic fluids into hydrothermal systems are just a few of the proposed processes induced by magmatic activity that affect the local hydrology. Aquifer responses are described to include changes in water table levels, changes in temperature or composition of hydrothermal waters and pore pressure-induced ground deformation. We can observe these effects at the surface via geophysical and geochemical signals. To fully to utilise these indicators as monitoring and forecasting tools, however, it is necessary to improve our still poor understanding of the ongoing mechanisms in the interactions of hydrological and magmatic systems. An extensive literature research provided an overview on reported effects, which we investigate in detail using numerical modelling. The hydrogeophysical study uses finite element analysis to quantitatively test proposed mechanisms of aquifer excitation and the resultant geophysical signals. We present a set of generic models for two typical volcanic landforms - a stratovolcano and a caldera - that simulate the interaction between deeper magmatic systems with shallow-seated aquifers, focusing on strain and temperature effects. They predict pore pressure induced hydraulic head changes in the aquifer as well as changing groundwater temperatures and strain induced fluid migration. Volcano observatories can track these hydrological effects for example with potential field investigations or the monitoring of wells. The models allow us to explore the parameter space, contributing to a better understanding of the coupling of these two highly complex systems. Our results provide further insight into the subsurface processes at volcanic systems and will aid the evaluation of unrest signals with potential for improved eruption forecasting.

Geophysical System Verification (GSV): A Physics-Based Alternative to Geophysical Prove-Outs for Munitions Response

DTIC Science & Technology

2015-09-24

engineering field, or equivalent experience, and are familiar with the basic MR processes. Section 2 summarizes the physical justification for the... Engineering Problems (SAGEEP), Seattle, April 2 -6, 2006. 8. Interstate Technology and Regulatory Council. 2004. “Geophysical Prove-Outs for Munitions Response...YOUR FORM TO THE ABOVE ORGANIZATION. 1. REPORT DATE (DD-MM-YYYY) 2 . REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER

Geophysical System Verification (GSV): A Physics-Based Alternative to Geophysical Prove-Outs for Munitions Response. Addendum

DTIC Science & Technology

2015-09-24

engineering field, or equivalent experience, and are familiar with the basic MR processes. Section 2 summarizes the physical justification for the... Engineering Problems (SAGEEP), Seattle, April 2 -6, 2006. 8. Interstate Technology and Regulatory Council. 2004. “Geophysical Prove-Outs for Munitions Response...YOUR FORM TO THE ABOVE ORGANIZATION. 1. REPORT DATE (DD-MM-YYYY) 2 . REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER

Field Geophysics at SAGE: Strategies for Effective Education

NASA Astrophysics Data System (ADS)

Braile, L. W.; Baldridge, W. S.; Jiracek, G. R.; Biehler, S.; Ferguson, J. F.; Pellerin, L.; McPhee, D. K.; Bedrosian, P. A.; Snelson, C. M.; Hasterok, D. P.

2011-12-01

SAGE (Summer of Applied Geophysical Experience) is a unique program of education and research in geophysical field methods for undergraduate and graduate students from any university and for professionals. The core program is held for 4 weeks each summer in New Mexico and for an additional week in the following academic year in San Diego for U.S. undergraduates supported by the NSF Research Experience for Undergraduates (REU) program. Since SAGE was initiated in 1983, 730 students have participated in the program. NSF REU funding for SAGE began in 1990 and 319 REU students have completed SAGE through 2011. The primary objectives of SAGE are to teach the major geophysical exploration methods (seismic, gravity, magnetics, electromagnetics); apply these methods to the solution of specific problems (environmental, archaeological, hydrologic, geologic structure and stratigraphy); gain experience in processing, modeling and interpretation of geophysical data; and integrate the geophysical models and interpretations with geology. Additional objectives of SAGE include conducting research on the Rio Grande rift of northern New Mexico, and providing information on geophysics careers and professional development experiences to SAGE participants. Successful education, field and research strategies that we have implemented over the years include: 1. learn by doing; 2. mix lecture/discussion, field work, data processing and analysis, modeling and interpretation, and presentation of results; 3. a two-tier team approach - method/technique oriented teams and interpretation/integration teams (where each team includes persons representing different methods), provides focus, in-depth study, opportunity for innovation, and promotes teamwork and a multi-disciplinary approach; 4. emphasis on presentations/reports - each team (and all team members) make presentation, each student completes a written report; 5. experiment design discussion - students help design field program and consider issues - safety, constraints, data quality/quantity, research objective, educational experience, survey parameters, why multidisciplinary?, etc.; 6. knowledge of multiple geophysical field methods (each student works with all methods); 7. information on geophysics careers and networking provided by industry visitors; 8. measures of success of the program include high rate of continuation to graduate school and careers in geophysics, support and feedback from industry participants and visitors, student evaluations at end of program, presentations at professional meetings, publications, and faculty evaluation of student work.

Sinkhole risk assessment by ERT: The case study of Sirino Lake (Basilicata, Italy)

NASA Astrophysics Data System (ADS)

Giampaolo, V.; Capozzoli, L.; Grimaldi, S.; Rizzo, E.

2016-01-01

The presence of natural or artificial lakes and reservoirs that can drain because of natural phenomena can generate catastrophic events affecting urban and agricultural areas next to the source area. Therefore, geophysical prospecting techniques have been applied in the study of Sirino Lake, which, during the last century, was affected by the sudden opening of small sinkholes, resulting in the almost total draining of the lake and in the sudden increase of water flow rates of distal springs. Two electrical resistivity tomographies (ERTs) were carried out across the lake, using electrode arrays located on land and across the water body. Self-potential (SP) data were acquired around the lake shore and the surrounding area. The geophysical prospecting contributed significant data toward explaining the unique hydrogeological characteristics of the lake. Integration of geophysical, geological, hydrogeological, and geomorphological data allowed us to estimate the thickness of the lacustrine deposits beneath the lake, to describe the main patterns of the subsurface fluid flows in the area, and to identify possible water escape routes causing the piping phenomena.

Research on the middle-of-receiver-spread assumption of the MASW method

USGS Publications Warehouse

Luo, Y.; Xia, J.; Liu, J.; Xu, Y.; Liu, Q.

2009-01-01

The multichannel analysis of surface wave (MASW) method has been effectively used to determine near-surface shear- (S-) wave velocity. Estimating the S-wave velocity profile from Rayleigh-wave measurements is straightforward. A three-step process is required to obtain S-wave velocity profiles: acquisition of a multiple number of multichannel records along a linear survey line by use of the roll-along mode, extraction of dispersion curves of Rayleigh waves, and inversion of dispersion curves for an S-wave velocity profile for each shot gather. A pseudo-2D S-wave velocity section can be generated by aligning 1D S-wave velocity models. In this process, it is very important to understand where the inverted 1D S-wave velocity profile should be located: the midpoint of each spread (a middle-of-receiver-spread assumption) or somewhere between the source and the last receiver. In other words, the extracted dispersion curve is determined by the geophysical structure within the geophone spread or strongly affected by the source geophysical structure. In this paper, dispersion curves of synthetic datasets and a real-world example are calculated by fixing the receiver spread and changing the source location. Results demonstrate that the dispersion curves are mainly determined by structures within a receiver spread. ?? 2008 Elsevier Ltd. All rights reserved.

Teaching machines to find mantle composition

NASA Astrophysics Data System (ADS)

Atkins, Suzanne; Tackley, Paul; Trampert, Jeannot; Valentine, Andrew

2017-04-01

The composition of the mantle affects many geodynamical processes by altering factors such as the density, the location of phase changes, and melting temperature. The inferences we make about mantle composition also determine how we interpret the changes in velocity, reflections, attenuation and scattering seen by seismologists. However, the bulk composition of the mantle is very poorly constrained. Inferences are made from meteorite samples, rock samples from the Earth and inferences made from geophysical data. All of these approaches require significant assumptions and the inferences made are subject to large uncertainties. Here we present a new method for inferring mantle composition, based on pattern recognition machine learning, which uses large scale in situ observations of the mantle to make fully probabilistic inferences of composition for convection simulations. Our method has an advantage over other petrological approaches because we use large scale geophysical observations. This means that we average over much greater length scales and do not need to rely on extrapolating from localised samples of the mantle or planetary disk. Another major advantage of our method is that it is fully probabilistic. This allows us to include all of the uncertainties inherent in the inference process, giving us far more information about the reliability of the result than other methods. Finally our method includes the impact of composition on mantle convection. This allows us to make much more precise inferences from geophysical data than other geophysical approaches, which attempt to invert one observation with no consideration of the relationship between convection and composition. We use a sampling based inversion method, using hundreds of convection simulations run using StagYY with self consistent mineral physics properties calculated using the PerpleX package. The observations from these simulations are used to train a neural network to make a probabilistic inference for major element oxide composition of the mantle. We find we can constrain bulk mantle FeO molar percent, FeO/MgO and FeO/SiO2 using observations of the temperature and density structure of the mantle in convection simulations.

Combinaison de méthodes géophysiques pour estimer la distribution spatiale des sols affectés par l'excès d'eau

NASA Astrophysics Data System (ADS)

Chaplot, Vincent; Walter, Christian; Curmi, Pierre; Hollier-Larousse, Alain; Robain, Henri

2004-04-01

Geophysical methods have already shown their interest for the continuous characterisation of soils over landscapes, rapidly and, non-intrusively. But in bottomland areas, difficulties are encountered in relating geophysical properties to soil spatial distribution due to large variations in the depth, texture and/or water content of soils. Indeed, respective variations of these parameters can result in ambiguous geophysical responses. For example, a decrease in soil water content, which causes an increase in electrical resistivity, may be offset by an increase in soil clay content, inducing a decrease in resistivity. The objective of this study was to improve the continuous characterisation of soils affected by an excess of water by using a combination of geophysical techniques. Three techniques, the radio-magnetotelluric (RMT), the ground penetrating radar (GPR) and the electrostatic quadrupole (ESQP) were implemented along eight representative transects where soils were extensively described. The soil cover shows a succession from downslope to upslope consisting in fibric Fluvisols, gleyic Fluvisols, and Albefluvisols. None of the geophysical methods allows us to distinguish all soil limits and to estimate the geometry of soil horizons. The ESQP discriminates Fluvisols from Albefluvisols, whereas the RMT above all reveals differences in soil material thickness, which do not permit to discriminate between these soils. In complement, the GPR allows the estimation of the geometry of organic horizons and anthropic structures, such as ditches. Finally, the combination of these three techniques allows us to assess the main features of soil spatial distribution in bottomlands. To cite this article: V. Chaplot et al., C. R. Geoscience 336 (2004).

Assesment on the performance of electrode arrays using image processing technique

NASA Astrophysics Data System (ADS)

Usman, N.; Khiruddin, A.; Nawawi, Mohd

2017-08-01

Interpreting inverted resistivity section is time consuming, tedious and requires other sources of information to be relevant geologically. Image processing technique was used in order to perform post inversion processing which make geophysical data interpretation easier. The inverted data sets were imported into the PCI Geomatica 9.0.1 for further processing. The data sets were clipped and merged together in order to match the coordinates of the three layers and permit pixel to pixel analysis. Dipole-dipole array is more sensitive to resistivity variation with depth in comparison with Werner-Schlumberger and pole-dipole. Image processing serves as good post-inversion tool in geophysical data processing.

An Integral, Multidisciplinary and Global Geophysical Field Experience for Undergraduates

NASA Astrophysics Data System (ADS)

Vázquez, O.; Carrillo, D. J.; Pérez-Campos, X.

2007-05-01

The udergraduate program of Geophysical Engineering at the School of Engineering, of the Univesidad Nacional Autónoma de México (UNAM), went through an update process that concluded in 2006. As part of the program, the student takes three geophysical prospecting courses (gravity and magnetics, electric, electromagnetics, and seismic methods). The older program required a three-week field experience for each course in order to gradute. The new program considers only one extended field experience. This work stresses the importance of international academic exchange, where undergraduate students could participate, such as the Summer of Applied Geophysical Experience (SAGE), and interaction with research programs, such as the MesoAmerican Subduction Experiment (MASE). Also, we propose a scheeme for this activity based on those examples; both of them have in common real geophysical problems, from which students could benefit. Our proposal covers academic and logistic aspects to be taken into account, enhancing the relevance of interaction between other academic institutions, industry, and UNAM, in order to obtain a broader view of geophysics.

BROADBAND DIGITAL GEOPHYSICAL TELEMETRY SYSTEM.

USGS Publications Warehouse

Seeley, Robert L.; Daniels, Jeffrey J.

1984-01-01

A system has been developed to simultaneously sample and transmit digital data from five remote geophysical data receiver stations to a control station that processes, displays, and stores the data. A microprocessor in each remote station receives commands from the control station over a single telemetry channel.

Fracture induced electromagnetic emissions: extending laboratory findings by observations at the geophysical scale

NASA Astrophysics Data System (ADS)

Potirakis, Stelios M.; Contoyiannis, Yiannis; Kopanas, John; Kalimeris, Anastasios; Antonopoulos, George; Peratzakis, Athanasios; Eftaxias, Konstantinos; Nomicos, Constantinos

2014-05-01

Under natural conditions, it is practically impossible to install an experimental network on the geophysical scale using the same instrumentations as in laboratory experiments for understanding, through the states of stress and strain and their time variation, the laws that govern the friction during the last stages of EQ generation, or to monitor (much less to control) the principal characteristics of a fracture process. Fracture-induced electromagnetic emissions (EME) in a wide range of frequency bands are sensitive to the micro-structural chances. Thus, their study constitutes a nondestructive method for the monitoring of the evolution of damage process at the laboratory scale. It has been suggested that fracture induced MHz-kHz electromagnetic (EM) emissions, which emerge from a few days up to a few hours before the main seismic shock occurrence permit a real time monitoring of the damage process during the last stages of earthquake preparation, as it happens at the laboratory scale. Since the EME are produced both in the case of the laboratory scale fracture and the EQ preparation process (geophysical scale fracture) they should present similar characteristics in these two scales. Therefore, both the laboratory experimenting scientists and the experimental scientists studying the pre-earthquake EME could benefit from each- other's results. Importantly, it is noted that when studying the fracture process by means of laboratory experiments, the fault growth process normally occurs violently in a fraction of a second. However, a major difference between the laboratory and natural processes is the order-of-magnitude differences in scale (in space and time), allowing the possibility of experimental observation at the geophysical scale for a range of physical processes which are not observable at the laboratory scale. Therefore, the study of fracture-induced EME is expected to reveal more information, especially for the last stages of the fracture process, when it is conducted at the geophysical scale. As a characteristic example, we discuss about the case of electromagnetic silence before the global rupture that was first observed in preseismic EME and recently was also observed in the EME measured during laboratory fracture experiments, completely revising the earlier views about the fracture-induced electromagnetic emissions.

Critical zone architecture and processes: a geophysical perspective

NASA Astrophysics Data System (ADS)

Holbrook, W. S.

2016-12-01

The "critical zone (CZ)," Earth's near-surface layer that reaches from treetop to bedrock, sustains terrestrial life by storing water and producing nutrients. Despite is central importance, however, the CZ remains poorly understood, due in part to the complexity of interacting biogeochemical and physical processes that take place there, and in part due to the difficulty of measuring CZ properties and processes at depth. Major outstanding questions include: What is the architecture of the CZ? How does that architecture vary across scales and across gradients in climate, lithology, topography, biology and regional states of stress? What processes control the architecture of the CZ? At what depth does weathering initiate, and what controls the rates at which it proceeds? Based on recent geophysical campaigns at seven Critical Zone Observatory (CZO) sites and several other locations, a geophysical perspective on CZ architecture and processes is emerging. CZ architecture can be usefully divided into four layers, each of which has distinct geophysical properties: soil, saprolite, weathered bedrock and protolith. The distribution of those layers across landscapes varies depending on protolith composition and internal structure, topography, climate (P/T) and the regional state of stress. Combined observations from deep CZ drilling, geophysics and geochemistry demonstrate that chemical weathering initiates deep in the CZ, in concert with mechanical weathering (fracturing), as chemical weathering appears concentrated along fractures in borehole walls. At the Calhoun CZO, the plagioclase weathering front occurs at nearly 40 m depth, at the base of a 25-m-thick layer of weathered bedrock. The principal boundary in porosity, however, occurs at the saprolite/weathered bedrock boundary: porosity decreases over an order of magnitude, from 50% to 5% over an 8-m-thick zone at the base of saprolite. Porosity in weathered bedrock is between 2-5%. Future progress will depend on (1) more tightly linked geophysical, geochemical, hydrological and drilling studies, (2) 3D and 4D studies of deep CZ structure, and (3) measurements at multiple scales in the CZ, from pores to plots to hillslopes to catchments.

Object-Oriented Programming When Developing Software in Geology and Geophysics

NASA Astrophysics Data System (ADS)

Ahmadulin, R. K.; Bakanovskaya, L. N.

2017-01-01

The paper reviews the role of object-oriented programming when developing software in geology and geophysics. Main stages have been identified at which it is worthwhile to apply principles of object-oriented programming when developing software in geology and geophysics. The research was based on a number of problems solved in Geology and Petroleum Production Institute. Distinctive features of these problems are given and areas of application of the object-oriented approach are identified. Developing applications in the sphere of geology and geophysics has shown that the process of creating such products is simplified due to the use of object-oriented programming, firstly when designing structures for data storage and graphical user interfaces.

The role of the geophysical template and environmental regimes in controlling stream-living trout populations

USGS Publications Warehouse

Penaluna, Brooke E.; Railsback, Steve F.; Dunham, Jason B.; Johnson, S.; Bilby, Richard E.; Skaugset, Arne E.

2015-01-01

The importance of multiple processes and instream factors to aquatic biota has been explored extensively, but questions remain about how local spatiotemporal variability of aquatic biota is tied to environmental regimes and the geophysical template of streams. We used an individual-based trout model to explore the relative role of the geophysical template versus environmental regimes on biomass of trout (Oncorhynchus clarkii clarkii). We parameterized the model with observed data from each of the four headwater streams (their local geophysical template and environmental regime) and then ran 12 simulations where we replaced environmental regimes (stream temperature, flow, turbidity) of a given stream with values from each neighboring stream while keeping the geophysical template fixed. We also performed single-parameter sensitivity analyses on the model results from each of the four streams. Although our modeled findings show that trout biomass is most responsive to changes in the geophysical template of streams, they also reveal that biomass is restricted by available habitat during seasonal low flow, which is a product of both the stream’s geophysical template and flow regime. Our modeled results suggest that differences in the geophysical template among streams render trout more or less sensitive to environmental change, emphasizing the importance of local fish–habitat relationships in streams.

Solfatara volcano subsurface imaging: two different approaches to process and interpret multi-variate data sets

NASA Astrophysics Data System (ADS)

Bernardinetti, Stefano; Bruno, Pier Paolo; Lavoué, François; Gresse, Marceau; Vandemeulebrouck, Jean; Revil, André

2017-04-01

The need to reduce model uncertainty and produce a more reliable geophysical imaging and interpretations is nowadays a fundamental task required to geophysics techniques applied in complex environments such as Solfatara Volcano. The use of independent geophysical methods allows to obtain many information on the subsurface due to the different sensitivities of the data towards parameters such as compressional and shearing wave velocities, bulk electrical conductivity, or density. The joint processing of these multiple physical properties can lead to a very detailed characterization of the subsurface and therefore enhance our imaging and our interpretation. In this work, we develop two different processing approaches based on reflection seismology and seismic P-wave tomography on one hand, and electrical data acquired over the same line, on the other hand. From these data, we obtain an image-guided electrical resistivity tomography and a post processing integration of tomographic results. The image-guided electrical resistivity tomography is obtained by regularizing the inversion of the electrical data with structural constraints extracted from a migrated seismic section using image processing tools. This approach enables to focus the reconstruction of electrical resistivity anomalies along the features visible in the seismic section, and acts as a guide for interpretation in terms of subsurface structures and processes. To integrate co-registrated P-wave velocity and electrical resistivity values, we apply a data mining tool, the k-means algorithm, to individuate relationships between the two set of variables. This algorithm permits to individuate different clusters with the objective to minimize the sum of squared Euclidean distances within each cluster and maximize it between clusters for the multivariate data set. We obtain a partitioning of the multivariate data set in a finite number of well-correlated clusters, representative of the optimum clustering of our geophysical variables (P-wave velocities and electrical resistivities). The result is an integrated tomography that shows a finite number of homogeneous geophysical facies, and therefore permits to highlight the main geological features of the subsurface.

Unified Geophysical Cloud Platform (UGCP) for Seismic Monitoring and other Geophysical Applications.

NASA Astrophysics Data System (ADS)

Synytsky, R.; Starovoit, Y. O.; Henadiy, S.; Lobzakov, V.; Kolesnikov, L.

2016-12-01

We present Unified Geophysical Cloud Platform (UGCP) or UniGeoCloud as an innovative approach for geophysical data processing in the Cloud environment with the ability to run any type of data processing software in isolated environment within the single Cloud platform. We've developed a simple and quick method of several open-source widely known software seismic packages (SeisComp3, Earthworm, Geotool, MSNoise) installation which does not require knowledge of system administration, configuration, OS compatibility issues etc. and other often annoying details preventing time wasting for system configuration work. Installation process is simplified as "mouse click" on selected software package from the Cloud market place. The main objective of the developed capability was the software tools conception with which users are able to design and install quickly their own highly reliable and highly available virtual IT-infrastructure for the organization of seismic (and in future other geophysical) data processing for either research or monitoring purposes. These tools provide access to any seismic station data available in open IP configuration from the different networks affiliated with different Institutions and Organizations. It allows also setting up your own network as you desire by selecting either regionally deployed stations or the worldwide global network based on stations selection form the global map. The processing software and products and research results could be easily monitored from everywhere using variety of user's devices form desk top computers to IT gadgets. Currents efforts of the development team are directed to achieve Scalability, Reliability and Sustainability (SRS) of proposed solutions allowing any user to run their applications with the confidence of no data loss and no failure of the monitoring or research software components. The system is suitable for quick rollout of NDC-in-Box software package developed for State Signatories and aimed for promotion of data processing collected by the IMS Network.

Measuring biogeochemical responses to pulses of water

NASA Astrophysics Data System (ADS)

Balcerak, Ernie

2012-05-01

Hydrologic pulses, temporary increases in water inputs such as bouts of precipitation, can affect biogeochemical processes in ecosystems by providing water and nutrient resources. However, ecosystem responses to the water vary. Harms and Grimm conducted experiments to determine how hydrologic pulses and existing moisture conditions interact to affect the biogeochemistry of desert floodplains. During dry and monsoon seasons at their study site in the floodplains of the San Pedro River in Arizona, the researchers experimentally added pulses of water and then measured emissions of several trace gases that are indicators of biological processes. They found that the size of the added hydrologic pulse strongly interacted with existing soil moisture conditions in determining emissions of some trace gases. For instance, following dry conditions, pulses of water stimulated carbon dioxide, methane, and nitric oxide emissions, with larger water pulses stimulating more emissions. However, when soil was already wet, the addition of water pulses had less effect on the emission of these gases. (Journal of Geophysical Research-Biogeosciences, doi:10.1029/2011JG001775, 2012)

pyGIMLi: An open-source library for modelling and inversion in geophysics

NASA Astrophysics Data System (ADS)

Rücker, Carsten; Günther, Thomas; Wagner, Florian M.

2017-12-01

Many tasks in applied geosciences cannot be solved by single measurements, but require the integration of geophysical, geotechnical and hydrological methods. Numerical simulation techniques are essential both for planning and interpretation, as well as for the process understanding of modern geophysical methods. These trends encourage open, simple, and modern software architectures aiming at a uniform interface for interdisciplinary and flexible modelling and inversion approaches. We present pyGIMLi (Python Library for Inversion and Modelling in Geophysics), an open-source framework that provides tools for modelling and inversion of various geophysical but also hydrological methods. The modelling component supplies discretization management and the numerical basis for finite-element and finite-volume solvers in 1D, 2D and 3D on arbitrarily structured meshes. The generalized inversion framework solves the minimization problem with a Gauss-Newton algorithm for any physical forward operator and provides opportunities for uncertainty and resolution analyses. More general requirements, such as flexible regularization strategies, time-lapse processing and different sorts of coupling individual methods are provided independently of the actual methods used. The usage of pyGIMLi is first demonstrated by solving the steady-state heat equation, followed by a demonstration of more complex capabilities for the combination of different geophysical data sets. A fully coupled hydrogeophysical inversion of electrical resistivity tomography (ERT) data of a simulated tracer experiment is presented that allows to directly reconstruct the underlying hydraulic conductivity distribution of the aquifer. Another example demonstrates the improvement of jointly inverting ERT and ultrasonic data with respect to saturation by a new approach that incorporates petrophysical relations in the inversion. Potential applications of the presented framework are manifold and include time-lapse, constrained, joint, and coupled inversions of various geophysical and hydrological data sets.

The 1990 Western Pacific Geophysics meeting

NASA Technical Reports Server (NTRS)

1990-01-01

The 1990 Western Pacific Geophysics Meeting was held in Kanazawa, Japan from 15-21 Aug. 1990. This was the first meeting of a new series of meetings for the American Geophysical Union, and it proved to be very successful in terms of the scientific program and attendance, which included over 1,000 participants. The intent of this meeting was an effort on the part of the American Geophysical Union (AGU) and several Japanese geophysical societies to gather individual Earth and space scientists at a major scientific meeting to focus on geophysical problems being studied in the western Pacific rim. The meeting was organized along the lines of a typical AGU annual meeting with some invited talks, many contributed talks, poster sessions, and with emphasis on presentations and informal discussions. The program committee consisted of scientists from both the U.S. and Japan. This meeting provided ample opportunities for U.S. and Japanese scientists to get to know each other and their works on a one-to-one basis. It was also a valuable opportunity for students studying geophysics to get together and interact with each other and with scientists from both the U.S. and Japan. There were 939 abstracts submitted to the conference and a total of 102 sessions designed as a result of the abstracts received. The topics of interest are as follows: space geodetic and observatory measurements for earthquake and tectonic studies; gravity, sea level, and vertical motion; variations in earth rotation and earth dynamics; sedimentary magnetism; global processes and precipitation; subsurface contaminant transport; U.S. Western Pacific Rim initiatives in hydrology; shelf and coastal circulation; tectonics, magmatism, and hydrothermal processes; earthquake prediction and hazard assessment; seismic wave propagation in realistic media; and dynamics and structure of plate boundaries and of the Earth's deep interior.

The Multi-factor Predictive Seis &Gis Model of Ecological, Genetical, Population Health Risk and Bio-geodynamic Processes In Geopathogenic Zones

NASA Astrophysics Data System (ADS)

Bondarenko, Y.

I. Goal and Scope. Human birth rate decrease, death-rate growth and increase of mu- tagenic deviations risk take place in geopathogenic and anthropogenic hazard zones. Such zones create unfavourable conditions for reproductive process of future genera- tions. These negative trends should be considered as a protective answer of the com- plex biosocial system to the appearance of natural and anthropogenic risk factors that are unfavourable for human health. The major goals of scientific evaluation and de- crease of risk of appearance of hazardous processes on the territory of Dnipropetrovsk, along with creation of the multi-factor predictive Spirit-Energy-Information Space "SEIS" & GIS Model of ecological, genetical and population health risk in connection with dangerous bio-geodynamic processes, were: multi-factor modeling and correla- tion of natural and anthropogenic environmental changes and those of human health; determination of indicators that show the risk of destruction structures appearance on different levels of organization and functioning of the city ecosystem (geophys- ical and geochemical fields, soil, hydrosphere, atmosphere, biosphere); analysis of regularities of natural, anthropogenic, and biological rhythms' interactions. II. Meth- ods. The long spatio-temporal researches (Y. Bondarenko, 1996, 2000) have proved that the ecological, genetic and epidemiological processes are in connection with de- velopment of dangerous bio-geophysical and bio-geodynamic processes. Mathemat- ical processing of space photos, lithogeochemical and geophysical maps with use of JEIS o and ERDAS o computer systems was executed at the first stage of forma- tion of multi-layer geoinformation model "Dnipropetrovsk ARC View GIS o. The multi-factor nonlinear correlation between solar activity and cosmic ray variations, geophysical, geodynamic, geochemical, atmospheric, technological, biological, socio- economical processes and oncologic case rate frequency, general and primary popula- tion sickness cases in Dnipropetrovsk City (1.2 million persons) are described by the multi-factor predictive SEIS & GIS model of geopathogenic zones that determines the human health risk and hazards. Results and Conclusions. We have created the SEIS system and multi-factor predictive SEIS model for the analysis of phase-metric spatio- 1 temporal nonlinear correlation and variations of rhythms of human health, ecological, genetic, epidemiological risks, demographic, socio-economic, bio-geophysical, bio- geodynamic processes in geopathogenic hazard zones. Cosmophotomaps "CPM" of vegetation index, anthropogenic-landscape and landscape-geophysical human health risk of Dnipropetrovsk City present synthesis-based elements of multi-layer GIS, which include multispectral images SPOT o, maps of different geophysical, geochem- ical, anthropogenic and citogenic risk factors, maps of integral oncologic case rate frequency, general and primary population sickness cases for administrative districts. Results of multi-layer spatio-temporal correlation of geophysical field parameters and variations of population sickness rate rhythms have enabled us to state grounds and to develop medico-biological and bio-geodynamic classification of geopathogenic zones. Bio-geodynamic model has served to define contours of anthropogenic-landscape and landscape-geophysical human health risk in Dnipropetrovsk City. Biorhythmic vari- ations give foundation for understanding physiological mechanisms of organism`s adaptation to extreme helio-geophysical and bio-geodynamic environmental condi- tions, which are dictated by changes in Multi-factor Correlation Stress Field "MCSF" with deformation of 5D SEIS. Interaction between organism and environment results in continuous superpositioning of external (exogenic) Nuclear-Molecular-Cristallic "NMC" MCSF rhythms on internal (endogenic) Nuclear-Molecular-Cellular "NMCl" MCSF rhythms. Their resonance wave (energy-information) integration and disinte- gration are responsible for structural and functional state of different physiological systems. Herewith, complex restructurization of defense functions blocks the adapta- tion process and may turn to be the primary reason for phase shifting, process and biorhythms hindering, appearance of different deseases. Interaction of biorhythms with natural and anthropogenic rhythms specify the peculiar features of environ- mental adaptation of living species. Such interaction results in correlation of sea- sonal rhythms in variations of thermo-baro-geodynamic "TBG" parameters of am- bient air with toxic concentration and human health risk in Dnipropetrovsk City. Bio-geodynamic analysis of medical and demographic situations has provided for search of spatio-temporal correlation between rhythms of general and primary pop- ulation sickness cases and oncologic case rate frequency, other medico-demographic rhythms, natural processes (helio-geophysical, thermodynamic, geodynamic) and an- thropogenic processes (industrial and houschold waste disposal, toxic emissions and their concentration in ambient air). The year of 1986, the year of minimum helio- geophysical activity "2G1dG1" and maximum anthropogenic processes associated with changes in sickness and death rates of the population of Earth were synchronized. With account of quantum character of SEIS rhythms, 5 reference levels of desyn- chronized helio-geophysical and bio-geodynamic processes affecting population sick- ness rate have been specified within bio-geodynamic models. The first reference level 2 of SEIS desynchronization includes rhythms with period of 22,5 years: ... 1958,2; 1980,7; 2003,2; .... The second reference level of SEIS desynchronization includes rhythms with period of 11,25 years: ... 1980,7; 1992; 2003,2;.... The third reference level covers 5,625-years periodic rhythms2:... 1980,7; 1986,3; 1992; 1997,6; 2003,2; .... The fourth quantum reference level includes rhythms 3 with period of 2,8125 years: ... 1980,7; 1983,5; 1986,3; 1989,1; 1992; 1994,8; 1997,6; 2000,4; 2003,2; .... Rhythms with 1,40625-years period fall is fifth reference level of SEIS desynchro- nization: ...1980,7; 1982,1; 1983,5; 1984,9; 1986,3; 1987,7; 1989,1; 1990,5; 1992; 1993,3; 1994,8; 1996,2; 1997,6; 1999; 2000,4; 2001,8; 2003,2;.... Analysis of alternat- ing medical and demographic situation in Ukraine (1981-1992)and in Dnipropetrovsk (1988-1995)has allowed to back up theoretical model of various-level rhythm quan- tum, with non-linear regularities due to phase-metric spatio-temporal deformation be- ing specified. Application of new technologies of Risk Analysis, Sinthesis and SEIS Modeling at the choice of a burial place for dangerous radioactive wastes in the zone of Chernobyl nuclear disaster (Shestopalov V., Bondarenko Y...., 1998) has shown their very high efficiency in comparison with GIS Analysis. IV.Recommendations and Outlook. In order to draw a conclusion regarding bio-geodynamic modeling of spatio-temporal structure of areas where common childhood sickness rate exists, it is necessary to mention that the only thing that can favour to exact predicting of where and when important catastrophes and epidemies will take place is correct and complex bio-geodynamic modeling. Imperfection of present GIS is the result of the lack of interactive facilities for multi-factor modeling of nonlinear natural and an- thropogenic processes. Equations' coefficients calculated for some areas are often irrelevant when applied to others. In this connection there arises a number of prob- lems concerning practical application and reliability of GIS-models that are used to carry out efficient ecological monitoring. References Bondarenko Y., 1997, Drawing up Cosmophotomaps and Multi-factor Forecasting of Hazard of Development of Dan- gerous Geodynamic Processes in Dnipropetrovsk,The Technically-Natural Problems of failures and catastrophes in connection with development of dangerous geological processes, Kiev, Ukraine, 1997. Bondarenko Y., 1997, The Methodology of a State the Value of Quality of the Ground and the House Level them Ecology-Genetic-Toxic of the human health risk based on multi-layer cartographical model", Experience of application GIS - Technologies for creating Cadastral Systems, Yalta, Ukraine, 1997, p. 39-40. Shestopalov V., Bondarenko Y., Zayonts I., Rudenko Y. , Bohuslavsky A., 1998, Complexation of Structural-Geodynamical and Hydrogeological Methods of Studying Areas to Reveal Geological Structural Perspectives for Deep Isolation of Radioactive Wastes, Field Testing and Associated Modeling of Potential High-Level Nuclear Waste Geologic Disposal Sites, Berkeley, USA, 1998, p.81-82. 3

Integrated geophysical investigations in a fault zone located on southwestern part of İzmir city, Western Anatolia, Turkey

NASA Astrophysics Data System (ADS)

Drahor, Mahmut G.; Berge, Meriç A.

2017-01-01

Integrated geophysical investigations consisting of joint application of various geophysical techniques have become a major tool of active tectonic investigations. The choice of integrated techniques depends on geological features, tectonic and fault characteristics of the study area, required resolution and penetration depth of used techniques and also financial supports. Therefore, fault geometry and offsets, sediment thickness and properties, features of folded strata and tectonic characteristics of near-surface sections of the subsurface could be thoroughly determined using integrated geophysical approaches. Although Ground Penetrating Radar (GPR), Electrical Resistivity Tomography (ERT) and Seismic Refraction Tomography (SRT) methods are commonly used in active tectonic investigations, other geophysical techniques will also contribute in obtaining of different properties in the complex geological environments of tectonically active sites. In this study, six different geophysical methods used to define faulting locations and characterizations around the study area. These are GPR, ERT, SRT, Very Low Frequency electromagnetic (VLF), magnetics and self-potential (SP). Overall integrated geophysical approaches used in this study gave us commonly important results about the near surface geological properties and faulting characteristics in the investigation area. After integrated interpretations of geophysical surveys, we determined an optimal trench location for paleoseismological studies. The main geological properties associated with faulting process obtained after trenching studies. In addition, geophysical results pointed out some indications concerning the active faulting mechanism in the area investigated. Consequently, the trenching studies indicate that the integrated approach of geophysical techniques applied on the fault problem reveals very useful and interpretative results in description of various properties of faulting zone in the investigation site.

Noninvasive characterization of the Trecate (Italy) crude-oil contaminated site: links between contamination and geophysical signals.

PubMed

Cassiani, Giorgio; Binley, Andrew; Kemna, Andreas; Wehrer, Markus; Orozco, Adrian Flores; Deiana, Rita; Boaga, Jacopo; Rossi, Matteo; Dietrich, Peter; Werban, Ulrike; Zschornack, Ludwig; Godio, Alberto; JafarGandomi, Arash; Deidda, Gian Piero

2014-01-01

The characterization of contaminated sites can benefit from the supplementation of direct investigations with a set of less invasive and more extensive measurements. A combination of geophysical methods and direct push techniques for contaminated land characterization has been proposed within the EU FP7 project ModelPROBE and the affiliated project SoilCAM. In this paper, we present results of the investigations conducted at the Trecate field site (NW Italy), which was affected in 1994 by crude oil contamination. The less invasive investigations include ground-penetrating radar (GPR), electrical resistivity tomography (ERT), and electromagnetic induction (EMI) surveys, together with direct push sampling and soil electrical conductivity (EC) logs. Many of the geophysical measurements were conducted in time-lapse mode in order to separate static and dynamic signals, the latter being linked to strong seasonal changes in water table elevations. The main challenge was to extract significant geophysical signals linked to contamination from the mix of geological and hydrological signals present at the site. The most significant aspects of this characterization are: (a) the geometrical link between the distribution of contamination and the site's heterogeneity, with particular regard to the presence of less permeable layers, as evidenced by the extensive surface geophysical measurements; and (b) the link between contamination and specific geophysical signals, particularly evident from cross-hole measurements. The extensive work conducted at the Trecate site shows how a combination of direct (e.g., chemical) and indirect (e.g., geophysical) investigations can lead to a comprehensive and solid understanding of a contaminated site's mechanisms.

The potential of near-surface geophysical methods in a hierarchical monitoring approach for the detection of shallow CO2 seeps at geological storage sites

NASA Astrophysics Data System (ADS)

Sauer, U.; Schuetze, C.; Dietrich, P.

2013-12-01

The MONACO project (Monitoring approach for geological CO2 storage sites using a hierarchic observation concept) aims to find reliable monitoring tools that work on different spatial and temporal scales at geological CO2 storage sites. This integrative hierarchical monitoring approach based on different levels of coverage and resolutions is proposed as a means of reliably detecting CO2 degassing areas at ground surface level and for identifying CO2 leakages from storage formations into the shallow subsurface, as well as CO2 releases into the atmosphere. As part of this integrative hierarchical monitoring concept, several methods and technologies from ground-based remote sensing (Open-path Fourier-transform infrared (OP-FTIR) spectroscopy), regional measurements (near-surface geophysics, chamber-based soil CO2 flux measurement) and local in-situ measurements (using shallow boreholes) will either be combined or used complementary to one another. The proposed combination is a suitable concept for investigating CO2 release sites. This also presents the possibility of adopting a modular monitoring concept whereby our monitoring approach can be expanded to incorporate other methods in various coverage scales at any temporal resolution. The link between information obtained from large-scale surveys and local in-situ monitoring can be realized by sufficient geophysical techniques for meso-scale monitoring, such as geoelectrical and self-potential (SP) surveys. These methods are useful for characterizing fluid flow and transport processes in permeable near-surface sedimentary layers and can yield important information concerning CO2-affected subsurface structures. Results of measurements carried out a natural analogue site in the Czech Republic indicate that the hierarchical monitoring approach represents a successful multidisciplinary modular concept that can be used to monitor both physical and chemical processes taking place during CO2 migration and seepage. The application of FTIR spectroscopy in combination with soil gas surveys and geophysical investigations results in a comprehensive site characterization, including atmospheric and near-surface CO2 distribution, as well as subsurface structural features. We observed a correlation of higher CO2 concentration and flux rates at the meso-scale that coincides with distinct geophysical anomalies. Here, we found prominent SP anomalies and zones of lower resistivity in the geoelectrical images compared to undisturbed regions nearby. This presentation will discuss the results we obtained and illustrate the influence of CO2 on electrical parameters measured under field conditions in relation to environmental parameters.

30 CFR 582.5 - Disclosure of data and information to the public.

Code of Federal Regulations, 2012 CFR

2012-07-01

... public. 582.5 Section 582.5 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE... or more leases, to ensure proper Mining Plans for a common orebody, or to promote operational safety...), unitization agreement, or joint Mining Plan. (c) Geophysical data, processed geophysical information, and...

30 CFR 582.5 - Disclosure of data and information to the public.

Code of Federal Regulations, 2013 CFR

2013-07-01

... public. 582.5 Section 582.5 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE... or more leases, to ensure proper Mining Plans for a common orebody, or to promote operational safety...), unitization agreement, or joint Mining Plan. (c) Geophysical data, processed geophysical information, and...

30 CFR 582.5 - Disclosure of data and information to the public.

Code of Federal Regulations, 2014 CFR

2014-07-01

... public. 582.5 Section 582.5 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE... or more leases, to ensure proper Mining Plans for a common orebody, or to promote operational safety...), unitization agreement, or joint Mining Plan. (c) Geophysical data, processed geophysical information, and...

Geophysical constraints for terrane boundaries in southern Mongolia

NASA Astrophysics Data System (ADS)

Guy, Alexandra; Schulmann, Karel; Munschy, Marc; Miehe, Jean-Marc; Edel, Jean-Bernard; Lexa, Ondrej; Fairhead, Derek

2014-05-01

The Central Asian Orogenic Belt (CAOB) is a typical accretionary orogen divided into numerous lithostratigraphic terranes corresponding to magmatic arcs, back arcs, continental basement blocks, accretionary wedges and metamorphic blocks. These terranes should be in theory characterized by contrasting magnetic and gravity signatures thanks to their different petrophysical properties. To test this hypothesis, the stratigraphically defined terranes in southern Mongolia were compared with potential field data to constrain their boundaries and extent. The existence of terranes in southern Mongolia cannot be attested by the uniform geophysical fabrics due to the lack of systematic correspondence between the high/low amplitude and high/low frequency geophysical domains and major terranes. Processed magnetic and gravity grids show that both gravity and magnetic lineaments are E-W trending in the west and correlate with direction of some geological units. In the east, both magnetic and gravity lineaments are disrupted by NE-SW trending heterogeneities resulting in complete blurring of the geophysical pattern. Correlation of magnetic signal with geological map shows that the magnetic highs coincide with late Carboniferous-early Permian volcanic and plutonic belts. The matched-filtering shows good continuity of signal to the depth located along the boundaries of these high magnetic anomalies which may imply presence of deeply rooted tectono-magmatic zones. The axes of high density bodies in the western and central part of the studied CAOB are characterized by periodic alternations of NW-SE trending high frequency and high amplitude gravity anomalies corresponding to late Permian to Triassic cleavage fronts up to 20 km wide. The matched-filtering analysis shows that the largest deformation zones are deeply rooted down to 20 km depth. Such a gravity signal is explained by the verticalization of high density mantle and lower crustal rocks due to localized vertical shearing associated to upright folding. The magnetic signal is interpreted to result from a giant Permo-Triassic magmatic event associated lithosphere scale deformation whereas the gravity pattern is related to post-accretionary shortening of the CAOB in between North China and Siberia cratons. The blurring of the gravity signals to the west is attributed to activity of Triassic dextral shear zones parallel to the eastern Siberian boundary later on affected by Cretaceous extension and magmatism affecting the whole of eastern Asia.

An Overview of OCTAV-UTLS (Observed Composition Trends and Variability in the UTLS), a SPARC Emerging Activity

NASA Astrophysics Data System (ADS)

Petropavlovskikh, I. V.; Manney, G. L.; Hoor, P. M.; Bourassa, A. E.; Braathen, G.; Chang, K. L.; Hegglin, M. I.; Kramarova, N. A.; Kunkel, D.; Lawrence, Z. D.; Leblanc, T.; Livesey, N. J.; Millan Valle, L. F.; Stiller, G. P.; Tegtmeier, S.; Thouret, V.; Voigt, C.; Walker, K. A.

2017-12-01

The distribution of tracers in the upper troposphere and lower stratosphere (UTLS) shows large spatial and temporal variability because of interactions of transport, chemical, and mixing processes near the tropopause, as well as variations in the location of the tropopause itself. This strongly affects quantitative estimates of the impact of radiatively active substances, including ozone and water vapour, on surface temperatures, and complicates diagnosis of dynamical processes such as stratosphere troposphere exchange (STE). The Stratosphere-troposphere Processes And their Role in Climate (SPARC) emerging activity OCTAV-UTLS (Observed Composition Trends and Variability in the UTLS) aims to reduce the uncertainties in trend estimates by accounting for these dynamically induced sources of variability. Achieving these goals by using existing UTLS trace gas observations from aircraft, ground-based, balloon and satellite platforms requires a consistent analysis of these different data with respect to the tropopause or the jets. As a central task for OCTAV-UTLS, we are developing and applying common metrics, calculated using the same reanalysis datasets, to compare UTLS data using geophysically-based coordinate systems including tropopause and upper tropospheric jet relative coordinates. In addition to assessing present day measurement capabilities, OCTAV-UTLS will assess gaps in current geographical / temporal sampling of the UTLS that limit our ability to determine atmospheric composition variability and trends. This talk will provide an overview of the OCTAV-UTLS activity and some examples of initial calculations of geophysically-based coordinates and comparisons of remapped data.

Market applications of Resistivity, Induced Polarisation, Magnetic Resonance and Electromagnetic methods for Groundwater Investigations, Mining Exploration, Environmental and Engineering Surveys

NASA Astrophysics Data System (ADS)

Bernard, J.

2012-12-01

The Manufacturers of geophysical instruments have been facing these past decades the fast evolution of the electronics and of the computer sciences. More automatisms have been introduced into the equipment and into the processing and interpretation software which may let believe that conducting geophysical surveys requires less understanding of the method and less experience than in the past. Hence some misunderstandings in the skills that are needed to make the geophysical results well integrated among the global information which the applied geologist needs to acquire to be successful in his applications. Globally, the demand in geophysical investigation goes towards more penetration depth, requiring more powerful transmitters, and towards a better resolution, requiring more data such as in 3D analysis. Budgets aspects strongly suggest a high efficiency in the field associated to high speed data processing. The innovation is required in all aspects of geophysics to fit with the market needs, including new technological (instruments, software) and methodological (methods, procedures, arrays) developments. The structures in charge of the geophysical work can be public organisations (institutes, ministries, geological surveys,…) or can come from the private sector (large companies, sub-contractors, consultants, …), each one of them getting their own constraints in the field work and in the processing and interpretation phases. In the applications concerning Groundwater investigations, Mining Exploration, Environmental and Engineering surveys, examples of data and their interpretation presently carried out all around the world will be presented for DC Resistivity (Vertical Electrical Sounding, 2D, 3D Resistivity Imaging, Resistivity Monitoring), Induced Polarisation (Time Domain 2D, 3D arrays for mining and environmental), Magnetic Resonance Sounding (direct detection and characterisation of groundwater) and Electromagnetic (multi-component and multi-spacing Frequency Domain Sounding and Profiling technique). The place that Geophysics takes in the market among the other investigation techniques is, and will remain, dependant on the quality of the results obtained, despite the uncertainties linked to the field (noise aspects) and to the interpretation (equivalence aspects), under the control of budget decisions.Resistivity Imaging measurements for groundwater investigations

Integrating hydrologic and geophysical data to constrain coastal surficial aquifer processes at multiple spatial and temporal scales

USGS Publications Warehouse

Schultz, Gregory M.; Ruppel, Carolyn; Fulton, Patrick; Hyndman, David W.; Day-Lewis, Frederick D.; Singha, Kamini

2007-01-01

Since 1997, repeated, coincident geophysical surveys and extensive hydrologic studies in shallow monitoring wells have been used to study static and dynamic processes associated with surface water-groundwater interaction at a range of spatial scales at the estuarine and ocean boundaries of an undeveloped, permeable barrier island in the Georgia part of the U.S. South Atlantic Bight. Because geophysical and hydrologic data measure different parameters, at different resolution and precision, and over vastly different spatial scales, reconciling the coincident data or even combining complementary inversion, hydrogeochemcial analyses and well-based groundwater monitoring, and, in some cases, limited vegetation mapping to demonstrate the utility of an integrative, multidisciplinary approach for elucidating groundwater processes at spatial scales (tens to thousands of meters) that are often difficult to capture with traditional hydrologic approaches. The case studies highlight regional aquifer characteristics, varying degrees of lateral saltwater intrusion at estuarine boundaries, complex subsurface salinity gradients at the ocean boundary, and imaging of submarsh groundwater discharge and possible free convection in the pore waters of a clastic marsh. This study also documents the use of geophysical techniques for detecting temporal changes in groundwater salinity regimes under natural (not forced) gradients at intratidal to interannual (1998-200 Southeastern U.S.A. drought) time scales.

Integrated Geologic, Hydrologic, and Geophysical Investigations of the Chesapeake Bay Impact Structure, Virginia, USA: A Multi-Agency Program

NASA Technical Reports Server (NTRS)

Gohn, G. S.; Bruce, T. S.; Catchings, R. D.; Emry, S. R.; Johnson, G. H.; Levine, J. S.; McFarland, E. R.; Poag, C. W.; Powars, D. S.

2001-01-01

The Chesapeake Bay impact structure is the focus of an ongoing federal-state-local research program. Recent core drilling and geophysical surveys address the formative processes and hydrogeologic properties of this major "wet-target" impact. Additional information is contained in the original extended abstract.

The Role of Geophysics in the New Global Tectonics

ERIC Educational Resources Information Center

Rudman, Albert J.

1969-01-01

Summarizes the developments in geophysics that have led to the concept of the new global tectonics, which attempts to explain such worldwide features as oceanic ridges and trenches, island arcs and young mountain chains, while it develops processes that cause earthquakes, volcanoes and major faulting. Evidence for the hypotheses of continental…

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

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

Active experiments in the ionosphere and geomagnetic field variations

NASA Astrophysics Data System (ADS)

Sivokon, V. P.; Cherneva, N. V.; Khomutov, S. Y.; Serovetnikov, A. S.

2014-11-01

Variations of ionospheric-magnetospheric relation energy, as one of the possible outer climatology factors, may be traced on the basis of analysis of natural geophysical phenomena such as ionosphere artificial radio radiation and magnetic storms. Experiments on active impact on the ionosphere have been carried out for quite a long time in Russia as well. The most modern heating stand is located in Alaska; it has been used within the HAARP Program. The possibility of this stand to affect geophysical fields, in particular, the geomagnetic field is of interest.

The new geophysical observatory in Northern Caucasus (Elbrus volcanic area) and results of studies of ULF magnetic variations preceding strong geodynamic events

NASA Astrophysics Data System (ADS)

Sobissevitch, Leonid E.; Sobissevitch, Alex L.; Kanonidi, Konstantin Kh.; Filippov, Ivan N.

2010-05-01

The new geophysical observatory for fundamental scientific studies of geophysical processes in the Elbrus volcanic area (Northern Caucasus) has been organized recently as a result of merging of five geophysical laboratories positioned round the Elbrus volcano and equipped with modern geophysical instruments including broadband tri-axial seismometers, quartz tilt-meters, magnetic variometers, geo-acoustic sensors, hi-precision distributed thermal sensors, gravimeters, and network-enabled data acquisition systems with precise GPS-timing and integrated monitoring of auxiliary parameters (variations on ambient humidity, atmospheric pressure etc). Two laboratories are located in the horizontal 4.3 km deep tunnel drilled under the mount Andyrchi, about 20 km from the Elbrus volcano. Analysis of multi-parameter streams of experimental data allows one to study the structure of geophysical wave fields induced by earthquakes and regional catastrophic events (including snow avalanches). On the basis of continuous observations carried out since 2007 there have been determined anomalous wave forms in ULF geomagnetic variations preceding strong seismic events with magnitude 7 or more. Mentioned wave forms may be natively related to processes of evolution of dilatational structures in a domain of forthcoming seismic event. Specific patterns in anomalous ULF wave forms are distinguished for undersea earthquakes and for earthquakes responsible for triggering tsunami events. Thus, it is possible to consider development of a future technology to suggest the possible area and the time frame of such class of catastrophic events with additional reference to forecast information (including acoustic, hydro-acoustic and geo-acoustic) being concurrently analyzed.

Automatic mapping of the base of aquifer — A case study from Morrill, Nebraska

USGS Publications Warehouse

Gulbrandsen, Mats Lundh; Ball, Lyndsay B.; Minsley, Burke J.; Hansen, Thomas Mejer

2017-01-01

When a geologist sets up a geologic model, various types of disparate information may be available, such as exposures, boreholes, and (or) geophysical data. In recent years, the amount of geophysical data available has been increasing, a trend that is only expected to continue. It is nontrivial (and often, in practice, impossible) for the geologist to take all the details of the geophysical data into account when setting up a geologic model. We have developed an approach that allows for the objective quantification of information from geophysical data and borehole observations in a way that is easy to integrate in the geologic modeling process. This will allow the geologist to make a geologic interpretation that is consistent with the geophysical information at hand. We have determined that automated interpretation of geologic layer boundaries using information from boreholes and geophysical data alone can provide a good geologic layer model, even before manual interpretation has begun. The workflow is implemented on a set of boreholes and airborne electromagnetic (AEM) data from Morrill, Nebraska. From the borehole logs, information about the depth to the base of aquifer (BOA) is extracted and used together with the AEM data to map a surface that represents this geologic contact. Finally, a comparison between our automated approach and a previous manual mapping of the BOA in the region validates the quality of the proposed method and suggests that this workflow will allow a much faster and objective geologic modeling process that is consistent with the available data.

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

Active experiments in the ionosphere and variations of geophysical and meteorological parameters

NASA Astrophysics Data System (ADS)

Sivokon, Vladimir; Cherneva, Nina; Shevtsov, Boris

Energy distribution in ionospheric-magnetospheric relations, as one of the possible external climatological factors, may be traced on the basis of the analysis of natural geophysical phenomena such as ionosphere artificial radio radiation and magnetic storms. Development of magnetic disturbances is, to some extent, associated with current variations in electrojet. In its turn, some technologies are known which may affect electrojet and its characteristics. The method, developed by the authors, is based on a complex comparison of different geophysical fields and allows us to determine the degree of active experiment effect on energy change in ionospheric-magnetospheric relations and to evaluate on this basis the degree of active experiment effect on climate in the ionosphere. Within the framework of RAS Presidium Program Project “Determination of climate-forming characteristic changes on the basis of monitoring of geophysical field variations”, investigations have been carried out, which showed the possibility of ionosphere modification effect on the energy of magnetospheric-ionospheric relations. Evaluation of possible climate changes considering ionospheric-magnetospheric relations has not been previously discussed.

Well casing-based geophysical sensor apparatus, system and method

DOEpatents

Daily, William D.

2010-03-09

A geophysical sensor apparatus, system, and method for use in, for example, oil well operations, and in particular using a network of sensors emplaced along and outside oil well casings to monitor critical parameters in an oil reservoir and provide geophysical data remote from the wells. Centralizers are affixed to the well casings and the sensors are located in the protective spheres afforded by the centralizers to keep from being damaged during casing emplacement. In this manner, geophysical data may be detected of a sub-surface volume, e.g. an oil reservoir, and transmitted for analysis. Preferably, data from multiple sensor types, such as ERT and seismic data are combined to provide real time knowledge of the reservoir and processes such as primary and secondary oil recovery.

MT+, integrating magnetotellurics to determine earth structure, physical state, and processes

USGS Publications Warehouse

Bedrosian, P.A.

2007-01-01

As one of the few deep-earth imaging techniques, magnetotellurics provides information on both the structure and physical state of the crust and upper mantle. Magnetotellurics is sensitive to electrical conductivity, which varies within the earth by many orders of magnitude and is modified by a range of earth processes. As with all geophysical techniques, magnetotellurics has a non-unique inverse problem and has limitations in resolution and sensitivity. As such, an integrated approach, either via the joint interpretation of independent geophysical models, or through the simultaneous inversion of independent data sets is valuable, and at times essential to an accurate interpretation. Magnetotelluric data and models are increasingly integrated with geological, geophysical and geochemical information. This review considers recent studies that illustrate the ways in which such information is combined, from qualitative comparisons to statistical correlation studies to multi-property inversions. Also emphasized are the range of problems addressed by these integrated approaches, and their value in elucidating earth structure, physical state, and processes. ?? Springer Science+Business Media B.V. 2007.

Geophysical Investigations of Crustal and Upper Mantle Structure of Oceanic Intraplate Volcanoes (OIVs)

NASA Astrophysics Data System (ADS)

Robinson, A. H.; Peirce, C.; Funnell, M.; Watts, A. B.; Grevemeyer, I.

2016-12-01

Oceanic intraplate volcanoes (OIVs) represent a record of the modification of the oceanic crust by volcanism related to a range of processes including hot-spots, small scale mantle convection, and localised lithospheric extension. Geophysical studies of OIVs show a diversity in crustal and upper mantle structures, proposed to exist on a spectrum between two end-members where the main control is the age of the lithosphere at the time of volcanism. This hypothesis states that where the lithosphere is older, colder, and thicker it is more resistant to vertical magmatism than younger, hotter, thinner lithosphere. It is suggested that the Moho acts as a density filter, permitting relatively buoyant magma to vertically intrude the crust, but preventing denser magma from ascending to shallow levels. A key control may therefore be the melting depth, known to affect magma composition, and itself related to lithosphere age. Combined geophysical approaches allow us to develop robust models for OIV crustal structures with quantifiable resolution and uncertainty. As a case study, we present results from a multi-approach geophysical experiment at the Louisville Ridge Seamount Chain, believed to have formed on young (<10 Ma) lithosphere, which aimed at characterising the along-ridge crustal structure. The wide-angle seismic crustal model, generated by independent forward and inverse travel-time modelling of picked arrivals, is tested against reflection and gravity data. We compare our observations with studies of other OIVs to test whether lithospheric age controls OIV structure. Comparisons are limited by the temporal and spatial distribution of lithosphere and volcano ages, but suggest the hypothesis does not hold for all OIV features. While age may be the main control on OIV structure, as it determines lithosphere thermal and mechanical properties, other factors such as thermal rejuvenation, mechanical weakening, and volcano load size and distribution, may also come into play.

SIGKit: a New Data-based Software for Learning Introductory Geophysics

NASA Astrophysics Data System (ADS)

Zhang, Y.; Kruse, S.; George, O.; Esmaeili, S.; Papadimitrios, K. S.; Bank, C. G.; Cadmus, A.; Kenneally, N.; Patton, K.; Brusher, J.

2016-12-01

Students of diverse academic backgrounds take introductory geophysics courses to learn the theory of a variety of measurement and analysis methods with the expectation to be able to apply their basic knowledge to real data. Ideally, such data is collected in field courses and also used in lecture-based courses because they provide a critical context for better learning and understanding of geophysical methods. Each method requires a separate software package for the data processing steps, and the complexity and variety of professional software makes the path through data processing to data interpretation a strenuous learning process for students and a challenging teaching task for instructors. SIGKit (Student Investigation of Geophysics Toolkit) being developed as a collaboration between the University of South Florida, the University of Toronto, and MathWorks intends to address these shortcomings by showing the most essential processing steps and allowing students to visualize the underlying physics of the various methods. It is based on MATLAB software and offered as an easy-to-use graphical user interface and packaged so it can run as an executable in the classroom and the field even on computers without MATLAB licenses. An evaluation of the software based on student feedback from focus-group interviews and think-aloud observations helps drive its development and refinement. The toolkit provides a logical gateway into the more sophisticated and costly software students will encounter later in their training and careers by combining essential visualization, modeling, processing, and analysis steps for seismic, GPR, magnetics, gravity, resistivity, and electromagnetic data.

Investigation of coastal areas in Northern Germany using airborne geophysical surveys

NASA Astrophysics Data System (ADS)

Miensopust, Marion; Siemon, Bernhard; Wiederhold, Helga; Steuer, Annika; Ibs-von Seht, Malte; Voß, Wolfgang; Meyer, Uwe

2014-05-01

Since 2000, the German Federal Institute for Geosciences and Natural Resources (BGR) carried out several airborne geophysical surveys in Northern Germany to investigate the coastal areas of the North Sea and some of the North and East Frisian Islands. Several of those surveys were conducted in cooperation with the Leibniz Institute for Applied Geophysics (LIAG). Two helicopter-borne geophysical systems were used, namely the BGR system, which collects simultaneously frequency-domain electromagnetic, magnetic and radiometric data, and the SkyTEM system, a time-domain electromagnetic system developed by the University of Aarhus. Airborne geophysical surveys enable to investigate huge areas almost completely with high lateral resolution in a relatively short time at economic cost. In general, the results can support geological and hydrogeological mapping. Of particular importance are the airborne electromagnetic results, as the surveyed parameter - the electrical conductivity - depends on both lithology and groundwater status. Therefore, they can reveal buried valleys and the distribution of sandy and clayey sediments as well as salinization zones and fresh-water occurrences. The often simultaneously recorded magnetic and radiometric data support the electromagnetic results. Lateral changes of Quaternary and Tertiary sediments (shallow source - several tens of metres) as well as evidences of the North German Basin (deep source - several kilometres) are revealed by the magnetic results. The radiometric data indicate the various mineral compositions of the soil sediments. This BGR/LIAG project aims to build up a geophysics data base (http://geophysics-database.de/) which contains all airborne geophysical data sets. However, the more significant effort is to create a reference data set as basis for monitoring climate or man-made induced changes of the salt-water/fresh-water interface at the German North Sea coast. The significance of problems for groundwater extraction and treatment caused by groundwater salinization is more and more increasing and particularly coastal areas are affected by a latent risk for the sustainable usage of aquifers.

Detecting Underground Mine Voids Using Complex Geophysical Techniques

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

Kaminski, V. F.; Harbert, W. P.; Hammack, R. W.

2006-12-01

In July 2006, the National Energy Technology Laboratory in collaboration with Department of Geology and Planetary Science, University of Pittsburgh conducted complex ground geophysical surveys of an area known to be underlain by shallow coal mines. Geophysical methods including electromagnetic induction, DC resistivity and seismic reflection were conducted. The purpose of these surveys was to: 1) verify underground mine voids based on a century-old mine map that showed subsurface mine workings georeferenced to match with present location of geophysical test-site located on the territory of Bruceton research center in Pittsburgh, PA, 2) deliniate mine workings that may be potentially filledmore » with electrically conductive water filtrate emerging from adjacent groundwater collectors and 3) establish an equipment calibration site for geophysical instruments. Data from electromagnetic and resistivity surveys were further processed and inverted using EM1DFM, EMIGMA or Earthimager 2D capablilities in order to generate conductivity/depth images. Anomaly maps were generated, that revealed the locations of potential mine openings.« less

Geophysical Tools, Challenges and Perspectives Related to Natural Hazards, Climate Change and Food Security

NASA Astrophysics Data System (ADS)

Fucugauchi, J. U.

2013-05-01

In the coming decades a changing climate and natural hazards will likely increase the vulnerability of agricultural and other food production infrastructures, posing increasing treats to industrialized and developing economies. While food security concerns affect us globally, the huge differences among countries in stocks, population size, poverty levels, economy, technologic development, transportation, health care systems and basic infrastructure will pose a much larger burden on populations in the developing and less developed world. In these economies, increase in the magnitude, duration and frequency of droughts, floods, hurricanes, rising sea levels, heat waves, thunderstorms, freezing events and other phenomena will pose severe costs on the population. For this presentation, we concentrate on a geophysical perspective of the problems, tools available, challenges and short and long-term perspectives. In many instances, a range of natural hazards are considered as unforeseen catastrophes, which suddenly affect without warning, resulting in major losses. Although the forecasting capacity in the different situations arising from climate change and natural hazards is still limited, there are a range of tools available to assess scenarios and forecast models for developing and implementing better mitigation strategies and prevention programs. Earth observation systems, geophysical instrumental networks, satellite observatories, improved understanding of phenomena, expanded global and regional databases, geographic information systems, higher capacity for computer modeling, numerical simulations, etc provide a scientific-technical framework for developing strategies. Hazard prevention and mitigation programs will result in high costs globally, however major costs and challenges concentrate on the less developed economies already affected by poverty, famines, health problems, social inequalities, poor infrastructure, low life expectancy, high population growth, inadequate education systems, immigration, economic crises, conflicts and other issues. Case history analyses and proposals for collaboration programs, know-how transfer and better use of geophysical tools, data, observatories and monitoring networks will be discussed.

Physical bases of the generation of short-term earthquake precursors: A complex model of ionization-induced geophysical processes in the lithosphere-atmosphere-ionosphere-magnetosphere system

NASA Astrophysics Data System (ADS)

Pulinets, S. A.; Ouzounov, D. P.; Karelin, A. V.; Davidenko, D. V.

2015-07-01

This paper describes the current understanding of the interaction between geospheres from a complex set of physical and chemical processes under the influence of ionization. The sources of ionization involve the Earth's natural radioactivity and its intensification before earthquakes in seismically active regions, anthropogenic radioactivity caused by nuclear weapon testing and accidents in nuclear power plants and radioactive waste storage, the impact of galactic and solar cosmic rays, and active geophysical experiments using artificial ionization equipment. This approach treats the environment as an open complex system with dissipation, where inherent processes can be considered in the framework of the synergistic approach. We demonstrate the synergy between the evolution of thermal and electromagnetic anomalies in the Earth's atmosphere, ionosphere, and magnetosphere. This makes it possible to determine the direction of the interaction process, which is especially important in applications related to short-term earthquake prediction. That is why the emphasis in this study is on the processes proceeding the final stage of earthquake preparation; the effects of other ionization sources are used to demonstrate that the model is versatile and broadly applicable in geophysics.

Solar wind monitor—a school geophysics project

NASA Astrophysics Data System (ADS)

Robinson, Ian

2018-05-01

Described is an established geophysics project to construct a solar wind monitor based on a nT resolution fluxgate magnetometer. Low-cost and appropriate from school to university level it incorporates elements of astrophysics, geophysics, electronics, programming, computer networking and signal processing. The system monitors the earth’s field in real-time uploading data and graphs to a website every few minutes. Modular design encourages construction and testing by teams of students as well as expansion and refinement. The system has been tested running unattended for months at a time. Both the hardware design and software is published as open-source [1, 10].

Multiple geophysical methods examining neotectonic blind structures in the Maradona valley, Central Precordillera (Argentina)

NASA Astrophysics Data System (ADS)

Lara, Gabriela; Klinger, Federico Lince; Perucca, Laura; Rojo, Guillermo; Vargas, Nicolás; Leiva, Flavia

2017-08-01

A high-resolution superficial geophysical study was carried out in an area of the retroarc region of the Andes mountains, located in the southwest of San Juan Province (31°45‧ S, 68°50‧ W), Central Precordillera of Argentina. The main objectives of this study were to confirm the presence of blind neotectonic structures and characterize them by observing variations in magnetic susceptibility, density and p-wave velocities. Geological evidence demonstrates the existence of a neotectonic fault scarps affecting Quaternary alluvial deposits in eastern piedmont of de Las Osamentas range, in addition to direct observation of the cinematic of this feature in several natural exposures. The Maradona valley is characterized by the imbricated eastern-vergence Maradona Fault System that uplifts Neogene sedimentary rocks (Albarracín Formation) over Quaternary (Late Pleistocene-Holocene) alluvial deposits. The combined application of different geophysical methods has allowed the characterization of a blind fault geometry also identified on a natural exposure. The magnetic data added to the gravimetric model, and its integration with a seismic profile clearly shows the existence of an anomalous zone, interpreted as uplifted blocks of Miocene sedimentary rocks of Formation Albarracín displaced over Quaternary deposits. The application and development of different geophysical methods, together with geological studies allow to significantly improving the knowledge of an area affected by Quaternary tectonic activity. Finally, this multidisciplinary study, applied in active blind structures is very relevant for future seismic hazard analysis on areas located very close to populated centers.

Integration of Geophysical and Geochemical Data

NASA Astrophysics Data System (ADS)

Yamagishi, Y.; Suzuki, K.; Tamura, H.; Nagao, H.; Yanaka, H.; Tsuboi, S.

2006-12-01

Integration of geochemical and geophysical data would give us a new insight to the nature of the Earth. It should advance our understanding for the dynamics of the Earth's interior and surface processes. Today various geochemical and geophysical data are available on Internet. These data are stored in various database systems. Each system is isolated and provides own format data. The goal of this study is to display both the geochemical and geophysical data obtained from such databases together visually. We adopt Google Earth as the presentation tool. Google Earth is virtual globe software and is provided free of charge by Google, Inc. Google Earth displays the Earth's surface using satellite images with mean resolution of ~15m. We display any graphical features on Google Earth by KML format file. We have developed softwares to convert geochemical and geophysical data to KML file. First of all, we tried to overlay data from Georoc and PetDB and seismic tomography data on Google Earth. Georoc and PetDB are both online database systems for geochemical data. The data format of Georoc is CSV and that of PetDB is Microsoft Excel. The format of tomography data we used is plain text. The conversion software can process these different file formats. The geochemical data (e. g. compositional abundance) is displayed as a three-dimensional column on the Earth's surface. The shape and color of the column mean the element type. The size and color tone vary according to the abundance of the element. The tomography data can be converted into a KML file for each depth. This overlay plot of geochemical data and tomography data should help us to correlate internal temperature anomalies to geochemical anomalies, which are observed at the surface of the Earth. Our tool can convert any geophysical and geochemical data to a KML as long as the data is associated with longitude and latitude. We are going to support more geophysical data formats. In addition, we are currently trying to obtain scientific insights for the Earth's interior based on the view of both geophysical and geochemical data on Google Earth.

Detecting a liquid and solid H2O layer by geophysical methods

NASA Astrophysics Data System (ADS)

Yoshikawa, K.; Romanovsky, V.; Tsapin, A.; Brown, J.

2002-12-01

The objective is to detect the hydrological and cryological structure of the cold continuous permafrost subsurface using geophysical methods. We believe that a lot of water potentially exists as solid and liquid phases underground on Mars. It is likely that the liquid fluid would be high in saline concentration (brine). The ground freezing process involves many hydrological processes including enrichment of the brine layer. The brine layer is an important environment for ancient and/or current life to exist on terrestrial permafrost regions. The existence of a Martian brine layer would increase the possibility of the existence of life, as on Earth. In situ electric resistivity measurement will be the most efficient method to determine brine layer as well as massive H2O ice in the permafrost. However, the wiring configuration is unlikely to operate on the remote planetary surface. Satellite-born Radar and/or EM methods will be the most accessible methods for detecting the hydrological and cryological structure. We are testing several geophysical methods at the brine layer site in Barrow and massive pingo ice site in Fairbanks, Alaska. The radar system is affected by the dielectric properties of subsurface materials, which allows for evidence of liquid phase in the frozen ground. The dielectric constant varies greatly between liquid water and frozen ground. The depth of the terrestrial (and probably Martian) brine layer is frequently located deeper than the maximum detecting depth of the impulse type of the ground penetrating radar system. Once we develop a radar system with a deeper penetrating capability (Lower frequency), the dispersion of the ground ice will be the key function for interpretation of these signals. We will improve and use radar signals to understand the hydrological and cryological structure in the permafrost. The core samples and borehole temperature data validate these radar signals.

Spatial heterogeneities and variability of karst hydro-system : insights from geophysics

NASA Astrophysics Data System (ADS)

Champollion, C.; Fores, B.; Lesparre, N.; Frederic, N.

2017-12-01

Heterogeneous systems such as karsts or fractured hydro-systems are challenging for both scientist and groundwater resources management. Karsts heterogeneities prevent the comparison and moreover the combination of data representative of different scales: borehole water level can generally not be used directly to interpret spring flow dynamic for example. The spatial heterogeneity has also an impact on the temporal variability of groundwater transfer and storage. Karst hydro-systems have characteristic non linear relation between precipitation amount and discharge at the outlets with threshold effects and a large variability of groundwater transit times In the presentation, geophysical field experiments conducted in karst hydro-system in the south of France are used to investigate groundwater transfer and storage variability at a scale of a few hundred meters. We focus on the added value of both geophysical time-lapse gravity experiments and 2D ERT imaging of the subsurface heterogeneities. Both gravity and ERT results can only be interpreted with large ambiguity or some strong a priori: the relation between resistivity and water content is not unique; almost no information about the processes can be inferred from the groundwater stock variations. The present study demonstrate how the ERT and gravity field experiments can be interpreted together in a coherent scheme with less ambiguity. First the geological and hydro-meteorological context is presented. Then the ERT field experiment including the processing and the results are detailed in the section about geophysical imaging of the heterogeneities. The gravity double difference (S2D) time-lapse experiment is described in the section about geophysical monitoring of the temporal variability. The following discussion demonstrate the impact of both experiments on the interpretation in terms of processes and heterogeneities.

Geoelectrical monitoring of simulated subsurface leakage to support high-hazard nuclear decommissioning at the Sellafield Site, UK.

PubMed

Kuras, Oliver; Wilkinson, Paul B; Meldrum, Philip I; Oxby, Lucy S; Uhlemann, Sebastian; Chambers, Jonathan E; Binley, Andrew; Graham, James; Smith, Nicholas T; Atherton, Nick

2016-10-01

A full-scale field experiment applying 4D (3D time-lapse) cross-borehole Electrical Resistivity Tomography (ERT) to the monitoring of simulated subsurface leakage was undertaken at a legacy nuclear waste silo at the Sellafield Site, UK. The experiment constituted the first application of geoelectrical monitoring in support of decommissioning work at a UK nuclear licensed site. Images of resistivity changes occurring since a baseline date prior to the simulated leaks revealed likely preferential pathways of silo liquor simulant flow in the vadose zone and upper groundwater system. Geophysical evidence was found to be compatible with historic contamination detected in permeable facies in sediment cores retrieved from the ERT boreholes. Results indicate that laterally discontinuous till units forming localized hydraulic barriers substantially affect flow patterns and contaminant transport in the shallow subsurface at Sellafield. We conclude that only geophysical imaging of the kind presented here has the potential to provide the detailed spatial and temporal information at the (sub-)meter scale needed to reduce the uncertainty in models of subsurface processes at nuclear sites. Copyright © 2016 British Geological Survey, NERC. Published by Elsevier B.V. All rights reserved.

Geophysical fingerprints of shallow cultural structures from microgravity and GPR measurements in the Church of St. George, Svätý Jur, Slovakia

NASA Astrophysics Data System (ADS)

Panisova, Jaroslava; Murín, Igor; Pašteka, Roman; Haličková, Jana; Brunčák, Peter; Pohánka, Vladimír; Papčo, Juraj; Milo, Peter

2016-04-01

Recording of the historic edifice using the state-of-the-art geodetic and geophysical techniques brings easier visualisation in form of a three-dimensional (3D) model, thus allowing better understanding of its historical construction by the public and non-experts. We have applied this approach at the Church of St. George, one of the most significant religious buildings in south-western Slovakia, which dominates a silhouette of the town Svätý Jur. The geodetic survey allowed to record the actual state of the church. The church exterior was surveyed using a total station. Due to the intricate shape of the interior components of the church, it was decided to use a terrestrial laser scanner to generate the point cloud data, which were processed into floor plan, elevations, sectional 2D drawings and 3D model. The geophysical survey was carried out in the interior of the church in order to identify potential subsurface anthropogenic structures. Microgravity and ground penetrating radar (GPR) methods were selected as the most effective geophysical tools for such task. In microgravity data processing we focused on the calculation and removal of the gravitational effects of the building masses. The main negative gravity anomalies of interest in the nave, which also have been confirmed by GPR measurements, are interpreted as medieval crypts. Another very important outcome of the geophysical survey is the discovery of the west wall foundations of the oldest Romanesque construction. From each geophysical data acquired we derived 3D polygonal models, which are compared to achieve more realistic picture of the subsurface structures. Verification of these structures by means of archaeological excavation has not been carried out yet.

Impact of geophysical model error for recovering temporal gravity field model

NASA Astrophysics Data System (ADS)

Zhou, Hao; Luo, Zhicai; Wu, Yihao; Li, Qiong; Xu, Chuang

2016-07-01

The impact of geophysical model error on recovered temporal gravity field models with both real and simulated GRACE observations is assessed in this paper. With real GRACE observations, we build four temporal gravity field models, i.e., HUST08a, HUST11a, HUST04 and HUST05. HUST08a and HUST11a are derived from different ocean tide models (EOT08a and EOT11a), while HUST04 and HUST05 are derived from different non-tidal models (AOD RL04 and AOD RL05). The statistical result shows that the discrepancies of the annual mass variability amplitudes in six river basins between HUST08a and HUST11a models, HUST04 and HUST05 models are all smaller than 1 cm, which demonstrates that geophysical model error slightly affects the current GRACE solutions. The impact of geophysical model error for future missions with more accurate satellite ranging is also assessed by simulation. The simulation results indicate that for current mission with range rate accuracy of 2.5 × 10- 7 m/s, observation error is the main reason for stripe error. However, when the range rate accuracy improves to 5.0 × 10- 8 m/s in the future mission, geophysical model error will be the main source for stripe error, which will limit the accuracy and spatial resolution of temporal gravity model. Therefore, observation error should be the primary error source taken into account at current range rate accuracy level, while more attention should be paid to improving the accuracy of background geophysical models for the future mission.

Speeding Up Geophysical Research Using Docker Containers Within Multi-Cloud Environment.

NASA Astrophysics Data System (ADS)

Synytsky, R.; Henadiy, S.; Lobzakov, V.; Kolesnikov, L.; Starovoit, Y. O.

2016-12-01

How useful are the geophysical observations in a scope of minimizing losses from natural disasters today? Does it help to decrease number of human victims during tsunami and earthquake? Unfortunately it's still at early stage these days. It's a big goal and achievement to make such observations more useful by improving early warning and prediction systems with the help of cloud computing. Cloud computing technologies have proved the ability to speed up application development in many areas for 10 years already. Cloud unlocks new opportunities for geoscientists by providing access to modern data processing tools and algorithms including real-time high-performance computing, big data processing, artificial intelligence and others. Emerging lightweight cloud technologies, such as Docker containers, are gaining wide traction in IT due to the fact of faster and more efficient deployment of different applications in a cloud environment. It allows to deploy and manage geophysical applications and systems in minutes across multiple clouds and data centers that becomes of utmost importance for the next generation applications. In this session we'll demonstrate how Docker containers technology within multi-cloud can accelerate the development of applications specifically designed for geophysical researches.

Space Geodesy Monitoring Mass Transport in Global Geophysical Fluids

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2004-01-01

Mass transports occurring in the atmosphere-hydrosphere-cryosphere-solid Earth-core system (the 'global geophysical fluids') are important geophysical phenomena. They occur on all temporal and spatial scales. Examples include air mass and ocean circulations, oceanic and solid tides, hydrological water and idsnow redistribution, mantle processes such as post-glacial rebound, earthquakes and tectonic motions, and core geodynamo activities. The temporal history and spatial pattern of such mass transport are often not amenable to direct observations. Space geodesy techniques, however, have proven to be an effective tool in monitorihg certain direct consequences of the mass transport, including Earth's rotation variations, gravitational field variations, and the geocenter motion. Considerable advances have been made in recent years in observing and understanding of these geodynamic effects. This paper will use several prominent examples to illustrate the triumphs in research over the past years under a 'Moore's law' in space geodesy. New space missions and projects promise to further advance our knowledge about the global mass transports. The latter contributes to our understanding of the geophysical processes that produce and regulate the mass transports, as well as of the solid Earth's response to such changes in terms of Earth's mechanical properties.

Assessment of multiple geophysical techniques for the characterization of municipal waste deposit sites

NASA Astrophysics Data System (ADS)

Gaël, Dumont; Tanguy, Robert; Nicolas, Marck; Frédéric, Nguyen

2017-10-01

In this study, we tested the ability of geophysical methods to characterize a large technical landfill installed in a former sand quarry. The geophysical surveys specifically aimed at delimitating the deposit site horizontal extension, at estimating its thickness and at characterizing the waste material composition (the moisture content in the present case). The site delimitation was conducted with electromagnetic (in-phase and out-of-phase) and magnetic (vertical gradient and total field) methods that clearly showed the transition between the waste deposit and the host formation. Regarding waste deposit thickness evaluation, electrical resistivity tomography appeared inefficient on this particularly thick deposit site. Thus, we propose a combination of horizontal to vertical noise spectral ratio (HVNSR) and multichannel analysis of the surface waves (MASW), which successfully determined the approximate waste deposit thickness in our test landfill. However, ERT appeared to be an appropriate tool to characterize the moisture content of the waste, which is of prior information for the organic waste biodegradation process. The global multi-scale and multi-method geophysical survey offers precious information for site rehabilitation studies, water content mitigation processes for enhanced biodegradation or landfill mining operation planning.

Collisional Processing of Comet and Asteroid Surfaces: Velocity Effects on Absorption Spectra

NASA Technical Reports Server (NTRS)

Lederer, S. M.; Jensen, E. A.; Wooden, D. H.; Lindsay, S. S.; Smith, D. C.; Nakamura-Messenger, K.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

2012-01-01

A new paradigm has emerged where 3.9 Gyr ago, a violent reshuffling reshaped the placement of small bodies in the solar system (the Nice model). Surface properties of these objects may have been affected by collisions caused by this event, and by collisions with other small bodies since their emplacement. These impacts affect the spectrographic observations of these bodies today. Shock effects (e.g., planar dislocations) manifest in minerals allowing astronomers to better understand geophysical impact processing that has occurred on small bodies. At the Experimental Impact Laboratory at NASA Johnson Space Center, we have impacted forsterite and enstatite across a range of velocities. We find that the amount of spectral variation, absorption wavelength, and full width half maximum of the absorbance peaks vary non-linearly with the velocity of the impact. We also find that the spectral variation increases with decreasing crystal size (single solid rock versus granular). Future analyses include quantification of the spectral changes with different impactor densities, temperature, and additional impact velocities. Results on diopside, fayalite, and magnesite can be found in Lederer et al., this meeting.

Integrated monitoring system for ground deformation hazard assessment in Telese Terme (Benevento province, Italy)

NASA Astrophysics Data System (ADS)

Tessitore, S.; Castiello, G.; Fedi, M.; Florio, G.; Fuschini, V.; Ramondini, M.; Calcaterra, D.

2012-04-01

TeleseTerme plain is characterized by a very articulated stratigraphy (levels of travertine, fluvial-marshy and pyroclastic deposits), that allows the occurrence of underground water circulation with overlapping aquifers. These aquifers are locally in pressure and, because of chemical characteristics and physical properties of the water, they may activate processes of accelerated travertine's corrosion; the consequence is the formation of cavity along the ground water's preferential flow paths, and the activation of subsidence and sinkholes phenomena. In particular test area includes two zones, where in 2002 and 2006 occurred two sinkholes events, classified as "piping sinkholes". The hazard evaluation was carried out trhought an integrated monitoring system, based on "traditional" techniques conduced "in situ", as geological-geomorphological and geophysical (microgravity) surveys, integrated by the most innovative techniques of Remote sensing interferometry(Advanced DInSAR Interferometry Techniques). The last allow to evaluate the ground deformation, characterized by a predominantvertical component (typical deformation of sinkholes and subsidence phenomena), and are well suited to operate a continuous and long monitoring ofvery extended areas. Through an initial analysis of the Permanent Scatterers available in the Telese municipality, we found the envelopes of the areal that contain PS with negative and positive mean velocities; these velocities showed the presence of a possible phenomenon of subsidence detected by ERS and ENVISAT satellites. Through interferometric processing of ENVISAT images, the soil deformations of 2002-2010 year sare evaluated and compared with the data obtainedby survey took "in situ" during the same period. The knowledge of the deformation's evolution of the area made it possible to organize a more focused future monitoring through traditional techniques of relief (with the help of geophysical methodologies). Since the zone affected by sinkhole phenomena is located in urbanized area, microgravity method was preferred to other geophysical methodologies. In fact, seismic, magnetic and electromagnetic techniques are strongly influenced by urban noise and this produces a low value of signal to noise ratio. The gravity exploration, based on the identification of anomalies in the Earth's gravity field by measuring the gravity acceleration, allows to define any inhomogeneities generated by sources at different densities in the subsurface structure, such as underground voids. Based on geological informations, geophysical models of the known cavities are made. Establishing the physical and geometrical characteristics of the voids it was possible compute the amplitudes and wavelengths of the expected geophysical signal, in order to establish the procedures of the executive acquisition phase. If the magnitude of the evolution of the sinkhole phenomenon will be detected by gravity observations, the time-lapse gravity monitoring will be an excellent tool at the base of risk mitigation.

Hedberg Research Conference on Fundamental Controls on Flow in Carbonates: Request for Travel Support for Post-Doctoral Fellows

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

Pyrak-Nolte, Laura J.

Carbonate reservoirs pose a scientific and engineering challenge to geophysical prediction and monitoring of fluid flow in the subsurface. Difficulties in interpreting hydrological, reservoir and other exploration data arise because carbonates are composed of a hierarchy of geological structures, constituents and processes that span a wide spectrum of length and time scales. What makes this problem particularly challenging is that length scales associated with physical structure and processes are often not discrete, but overlap, preventing the definition of discrete elements at one scale to become the building blocks of the next scale. This is particularly true for carbonates where complicatedmore » depositional environments, subsequent post-deposition diagenesis and geochemical interactions result in pores that vary in scale from submicron to centimeters to fractures, variation in fabric composition with fossils, minerals and cement, as well as variations in structural features (e.g., oriented inter- and intra layered - interlaced bedding and/or discontinuous rock units). In addition, this complexity is altered by natural and anthropogenic processes such as changes in stress, fluid content, reactive fluid flow, etc. Thus an accurate geophysical assessment of the flow behavior of carbonate reservoirs requires a fundamental understanding of the interplay of textural and structural features subjected to physical processes that affect and occur on various length and time scales. To address this complexity related to carbonates, a Hedberg conference on “Fundamental Controls on Flow in Carbonates” was held July 8 to 13, 2012, to bring together industry and academic scientists to stimulate innovative ideas that can accelerate research advances related to flow prediction and recovery in carbonate reservoirs. Participants included scientist and engineers from multiple disciplines (such as hydrology, structural geology, geochemistry, reservoir engineering, geophysics, geomechanics, numerical modeling, physical experiments, sedimentology, well-testing, statistics, mathematics, visualization, etc.) who encompass experience as well as the latest advances in these multi-faceted fields. One of the goals was to include early career scientists and engineers (post-doctoral fellows, assistant professors, etc.). With this grant 10 early career scientists and engineers were supported to attend the conference. This reports contains a brief overview of the conference and the list of support participants supported by this grant. Full details of the outcomes of the conference are given in the publication found in the Attachment section of this report.« less

Conduct of Geologic Field Work During Planetary Exploration: Why Geology Matters

NASA Technical Reports Server (NTRS)

Eppler, Dean B.

2010-01-01

The science of field geology is the investigative process of determining the distribution of rock units and structures on a planet fs surface, and it is the first-order data set that informs all subsequent studies of a planet, such as geochemistry, geochronology, geophysics, or remote sensing. For future missions to the Moon and Mars, the surface systems deployed must support the conduct of field geology if these endeavors are to be scientifically useful. This lecture discussed what field geology is all about.why it is important, how it is done, how conducting field geology informs many other sciences, and how it affects the design of surface systems and the implementation of operations in the future.

The facts on file. Dictionary of geology and geophysics

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

Lapidus, D.F.; Coates, D.R.

1987-01-01

This reference to the basic vocabulary of geology and geophysics has more than 3,000 clear and concise entries defining the entire range of geological phenomena. This book covers such areas as types of rocks and rock formations, deformation processes such as erosion and plate tectonics, volcanoes, glaciers and their effects on topography, geodesy and survey methods, earthquakes and seismology, fuels and mineral deposits.

The University of Texas Institute for Geophysics Marine Geology and Geophysics Field Course

NASA Astrophysics Data System (ADS)

Duncan, D.; Davis, M. B.; Goff, J. A.; Gulick, S. P. S.; McIntosh, K. D.; Saustrup, S., Sr.

2014-12-01

The University of Texas Institute for Geophysics, part of the Jackson School of Geosciences, annually offers a three-week marine geology and geophysics field course during the spring-summer intersession. The course provides hands-on instruction and training for graduate and upper-level undergraduate students in high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, several types of sediment coring, grab sampling, and the sedimentology of resulting seabed samples. Students participate in an initial three days of classroom instruction designed to communicate geological context of the field area along with theoretical and technical background on each field method. The class then travels to the Gulf Coast for a week of at-sea field work. Our field sites at Port Aransas, and Galveston, TX, and Grand Isle, LA, provide ideal locations for students to investigate coastal processes of the Gulf Coast and continental shelf through application of geophysical techniques in an exploratory mode. At sea, students assist with survey design and instrumentation set up while learning about acquisition parameters, data quality control, trouble-shooting, and safe instrument deployment and retrieval. In teams of four, students work in onshore field labs preparing sediment samples for particle size analysis and data processing. During the course's final week, teams return to the classroom where they integrate, interpret, and visualize data in a final project using industry-standard software such as Echos, Landmark, Caris, and Fledermaus. The course concludes with a series of final presentations and discussions in which students examine geologic history and/or sedimentary processes represented by the Gulf Coast continental shelf with academic and industry supporters. Students report a greater understanding of marine geology and geophysics through the course's intensive, hands-on, team approach and low instructor to student ratio (sixteen students, three faculty, and three teaching assistants). This course (to our knowledge) remains the only one of its kind, satisfies field experience requirements for some degree programs, and provides an alternative to land-based field courses. www.ig.utexas.edu/research/mgg/courses/geof348K/

A Hands-on Approach to Teaching Geophysics through the University of Texas Institute for Geophysics Marine Geology and Geophysics Field Course in the Gulf of Mexico.

NASA Astrophysics Data System (ADS)

Duncan, D.; Davis, M. B.; Goff, J.; Gulick, S. P. S.; Fernandez-Vasquez, R. A.; Saustrup, S.

2017-12-01

The three week field course is offered to graduate and upper-level undergraduate students as hands-on instruction and training for marine geology and geophysics applications. Instructors provide theoretical and technical background of high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, sediment coring, grab sampling, and the sedimentology of resulting seabed samples in the initial phase of the course. The class then travels to the Gulf Coast for a week of at-sea field work. Over the last 10 years, field sites at Freeport, Port Aransas, and Galveston, TX, and Grand Isle, LA, have provided ideal locations for students to explore and investigate coastal and continental shelf processes through the application of geophysical techniques. Students with various backgrounds work in teams of four and rotate between two marine vessels: the R/V Scott Petty, a 26' vessel owned and operated by UTIG, and the R/V Manta, an 82' vessel owned and operated by NOAA. They assist with survey design, instrumentation setup and breakdown, data acquisition, trouble-shooting, data quality control, and safe instrumentation deployment and recovery. Teams also process data and sediment samples in an onshore field lab. During the final week, students visualize, integrate and interpret data for a final project using industry software. The course concludes with final presentations and discussions wherein students examine Gulf Coast geological history and sedimentary processes with academic and industry supporters. Students report a greater understanding of marine geology and geophysics through the course's intensive, hands-on, team approach and low instructor to student ratio (sixteen students, three faculty, and three teaching assistants). Post-class, students may incorporate course data in senior honors or graduate thesis and are encouraged to publish and present results at national meetings. This course satisfies field experience requirements for some degree programs, provides an alternative to land-based field courses and to our knowledge, remains the only class of its kind. Alumni note the course's applicability to energy, environmental, and geotechnical industries as well as coastal restoration/management fields.

Geophysical Methods for Investigating Ground-Water Recharge

USGS Publications Warehouse

Ferre, Ty P.A.; Binley, Andrew M.; Blasch, Kyle W.; Callegary, James B.; Crawford, Steven M.; Fink, James B.; Flint, Alan L.; Flint, Lorraine E.; Hoffmann, John P.; Izbicki, John A.; Levitt, Marc T.; Pool, Donald R.; Scanlon, Bridget R.

2007-01-01

While numerical modeling has revolutionized our understanding of basin-scale hydrologic processes, such models rely almost exclusively on traditional measurements?rainfall, streamflow, and water-table elevations?for calibration and testing. Model calibration provides initial estimates of ground-water recharge. Calibrated models are important yet crude tools for addressing questions about the spatial and temporal distribution of recharge. An inverse approach to recharge estimation is taken of necessity, due to inherent difficulties in making direct measurements of flow across the water table. Difficulties arise because recharging fluxes are typically small, even in humid regions, and because the location of the water table changes with time. Deep water tables in arid and semiarid regions make recharge monitoring especially difficult. Nevertheless, recharge monitoring must advance in order to improve assessments of ground-water recharge. Improved characterization of basin-scale recharge is critical for informed water-resources management. Difficulties in directly measuring recharge have prompted many efforts to develop indirect methods. The mass-balance approach of estimating recharge as the residual of generally much larger terms has persisted despite the use of increasing complex and finely gridded large-scale hydrologic models. Geophysical data pertaining to recharge rates, timing, and patterns have the potential to substantially improve modeling efforts by providing information on boundary conditions, by constraining model inputs, by testing simplifying assumptions, and by identifying the spatial and temporal resolutions needed to predict recharge to a specified tolerance in space and in time. Moreover, under certain conditions, geophysical measurements can yield direct estimates of recharge rates or changes in water storage, largely eliminating the need for indirect measures of recharge. This appendix presents an overview of physically based, geophysical methods that are currently available or under development for recharge monitoring. The material is written primarily for hydrogeologists. Uses of geophysical methods for improving recharge monitoring are explored through brief discussions and case studies. The intent is to indicate how geophysical methods can be used effectively in studying recharge processes and quantifying recharge. As such, the material constructs a framework for matching the strengths of individual geophysical methods with the manners in which they can be applied for hydrologic analyses. The appendix is organized in three sections. First, the key hydrologic parameters necessary to determine the rate, timing, and patterns of recharge are identified. Second, the basic operating principals of the relevant geophysical methods are discussed. Methods are grouped by the physical property that they measure directly. Each measured property is related to one or more of the key hydrologic properties for recharge monitoring. Third, the emerging conceptual framework for applying geophysics to recharge monitoring is presented. Examples of the application of selected geophysical methods to recharge monitoring are presented in nine case studies. These studies illustrate hydrogeophysical applications under a wide range of conditions and measurement scales, which vary from tenths of a meter to hundreds of meters. The case studies include practice-proven as well as emerging applications of geophysical methods to recharge monitoring.

A new GNSS velocity field for Fennoscandia and comparison to GIA models (Invited)

NASA Astrophysics Data System (ADS)

Kierulf, H. P.; Simpson, M. J.; Steffen, H.; Lidberg, M.

2013-12-01

In Fennoscandia, the process of Glacial Isostatic Adjustment (GIA) causes ongoing crustal deformation. The vertical and horizontal movements of the Earth can be measured to a high degree of precision using Global Navigation Satellite System (GNSS). The GNSS network in Fennoscandia has gradually been established since the early 1990s and today contains a dense network well suited for geophysical studies and especially GIA. We will present new velocity estimates for the Fennoscandian and North-European GNSS network using the processing package GAMIT/GLOBK. GNSS measurements have proved to be a good tool to constrain and validate GIA models. However, reference frame uncertainties, plate tectonics as well as intra-plate deformations might decontaminate the results. Different ITRFs have had large discrepancies, especially in the TZ-component, which have made the geophysical interpretation of GNSS results difficult. In GIA areas the uncertainties in the TZ component almost directly affect the height component which makes constraining of GIA models less reliable. Plate tectonics introduces large horizontal velocities which are hard to distinguish from horizontal GIA-induced velocities. We will present a new approach where our GNSS velocity field is directly realized in a GIA frame. With this approach, the effect of systematic errors in the reference frames and 'biasing' signal from the plate tectonics will be reduced to a minimum for our GIA results. Moreover, we are able to provide consistent GIA-free plate velocities for the Eurasian plate.

Design strategies for human & earth systems modeling to meet emerging multi-scale decision support needs

NASA Astrophysics Data System (ADS)

Spak, S.; Pooley, M.

2012-12-01

The next generation of coupled human and earth systems models promises immense potential and grand challenges as they transition toward new roles as core tools for defining and living within planetary boundaries. New frontiers in community model development include not only computational, organizational, and geophysical process questions, but also the twin objectives of more meaningfully integrating the human dimension and extending applicability to informing policy decisions on a range of new and interconnected issues. We approach these challenges by posing key policy questions that require more comprehensive coupled human and geophysical models, identify necessary model and organizational processes and outputs, and work backwards to determine design criteria in response to these needs. We find that modular community earth system model design must: * seamlessly scale in space (global to urban) and time (nowcasting to paleo-studies) and fully coupled on all component systems * automatically differentiate to provide complete coupled forward and adjoint models for sensitivity studies, optimization applications, and 4DVAR assimilation across Earth and human observing systems * incorporate diagnostic tools to quantify uncertainty in couplings, and in how human activity affects them * integrate accessible community development and application with JIT-compilation, cloud computing, game-oriented interfaces, and crowd-sourced problem-solving We outline accessible near-term objectives toward these goals, and describe attempts to incorporate these design objectives in recent pilot activities using atmosphere-land-ocean-biosphere-human models (WRF-Chem, IBIS, UrbanSim) at urban and regional scales for policy applications in climate, energy, and air quality.

Topics in geophysical fluid dynamics: Atmospheric dynamics, dynamo theory, and climate dynamics

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

Ghil, M.; Childress, S.

1987-01-01

This text is the first study to apply systematically the successive bifurcations approach to complex time-dependent processes in large scale atmospheric dynamics, geomagnetism, and theoretical climate dynamics. The presentation of recent results on planetary-scale phenomena in the earth's atmosphere, ocean, cryosphere, mantle and core provides an integral account of mathematical theory and methods together with physical phenomena and processes. The authors address a number of problems in rapidly developing areas of geophysics, bringing into closer contact the modern tools of nonlinear mathematics and the novel problems of global change in the environment.

Virtual Geophysics Laboratory: Exploiting the Cloud and Empowering Geophysicsts

NASA Astrophysics Data System (ADS)

Fraser, Ryan; Vote, Josh; Goh, Richard; Cox, Simon

2013-04-01

Over the last five decades geoscientists from Australian state and federal agencies have collected and assembled around 3 Petabytes of geoscience data sets under public funding. As a consequence of technological progress, data is now being acquired at exponential rates and in higher resolution than ever before. Effective use of these big data sets challenges the storage and computational infrastructure of most organizations. The Virtual Geophysics Laboratory (VGL) is a scientific workflow portal addresses some of the resulting issues by providing Australian geophysicists with access to a Web 2.0 or Rich Internet Application (RIA) based integrated environment that exploits eResearch tools and Cloud computing technology, and promotes collaboration between the user community. VGL simplifies and automates large portions of what were previously manually intensive scientific workflow processes, allowing scientists to focus on the natural science problems, rather than computer science and IT. A number of geophysical processing codes are incorporated to support multiple workflows. For example a gravity inversion can be performed by combining the Escript/Finley codes (from the University of Queensland) with the gravity data registered in VGL. Likewise, tectonic processes can also be modeled by combining the Underworld code (from Monash University) with one of the various 3D models available to VGL. Cloud services provide scalable and cost effective compute resources. VGL is built on top of mature standards-compliant information services, many deployed using the Spatial Information Services Stack (SISS), which provides direct access to geophysical data. A large number of data sets from Geoscience Australia assist users in data discovery. GeoNetwork provides a metadata catalog to store workflow results for future use, discovery and provenance tracking. VGL has been developed in collaboration with the research community using incremental software development practices and open source tools. While developed to provide the geophysics research community with a sustainable platform and scalable infrastructure; VGL has also developed a number of concepts, patterns and generic components of which have been reused for cases beyond geophysics, including natural hazards, satellite processing and other areas requiring spatial data discovery and processing. Future plans for VGL include a number of improvements in both functional and non-functional areas in response to its user community needs and advancement in information technologies. In particular, research is underway in the following areas (a) distributed and parallel workflow processing in the cloud, (b) seamless integration with various cloud providers, and (c) integration with virtual laboratories representing other science domains. Acknowledgements: VGL was developed by CSIRO in collaboration with Geoscience Australia, National Computational Infrastructure, Australia National University, Monash University and University of Queensland, and has been supported by the Australian Government's Education Investment Funds through NeCTAR.

Marine Geology and Geophysics Field Course Offered by The University of Texas Institute for Geophysics

NASA Astrophysics Data System (ADS)

Duncan, D.; Davis, M. B.; Allison, M. A.; Gulick, S. P.; Goff, J. A.; Saustrup, S.

2012-12-01

The University of Texas Institute for Geophysics, part of the Jackson School of Geosciences, annually offers an intensive three-week marine geology and geophysics field course during the spring-summer intersession. Now in year six, the course provides hands-on instruction and training for graduate and upper-level undergraduate students in data acquisition, processing, interpretation, and visualization. Techniques covered include high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, several types of sediment coring, grab sampling, and the sedimentology of resulting seabed samples (e.g., core description, grain size analysis, x-radiography, etc.). Students participate in an initial period of classroom instruction designed to communicate geological context of the field area (which changes each year) along with theoretical and technical background on each field method. The class then travels to the Gulf Coast for a week of at-sea field work. Our field sites at Port Aransas and Galveston, Texas, and Grand Isle, Louisiana, have provided ideal locations for students to investigate coastal and sedimentary processes of the Gulf Coast and continental shelf through application of geophysical techniques. In the field, students rotate between two research vessels: one vessel, the 22' aluminum-hulled R/V Lake Itasca, owned and operated by UTIG, is used principally for multibeam bathymetry, sidescan sonar, and sediment sampling; the other, NOAA's R/V Manta or the R/V Acadiana, operated by the Louisiana Universities Marine Consortium, and is used primarily for high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, gravity coring, and vibrocoring. While at sea, students assist with survey design, learn instrumentation set up, acquisition parameters, data quality control, and safe instrument deployment and retrieval. In teams of three, students work in onshore field labs preparing sediment samples for particle size analysis and initial post-processing of geophysical data. During the course's final week, teams return to the classroom where they integrate, interpret, and visualize data in a final project using industry-standard software such as Focus, Landmark, Caris, and Fledermaus. The course concludes with a series of professional-level final presentations and discussions with academic and industry supporters in which students examine the geologic history and sedimentary processes of the studied area of the Gulf Coast continental shelf. After completion, students report a greater understanding of marine geology and geophysics through the course's intensive, hands-on, team approach and low instructor to student ratio (12 students, three faculty, and three teaching assistants). This course satisfies field experience requirements for some degree programs and thus provides a unique alternative to land-based field courses.

EDITORIAL: Special issue on near surface geophysics for the study and the management of historical resources Special issue on near surface geophysics for the study and the management of historical resources

NASA Astrophysics Data System (ADS)

Eppelbaum, L. V.; Masini, N.; Soldovieri, F.

2010-06-01

This special issue of the Journal of Geophysics and Engineering hosts a selection of the papers that were presented at the session entitled `Near surface geophysics for the study and the management of historical resources: past, present and future', organized within the framework of the General Assembly of the European Geosciences Union (Vienna, Austria, 19-24 April 2009). As the conveners, we invited the active participants of this session to prepare papers reflecting their presentations and submit them for publication in the Journal of Geophysics and Engineering. This special issue presents the papers which have passed through the prolonged and stringent reviewing process. The papers presented in this issue illustrate the application of novel instrumentation, surface and airborne remote sensing techniques, as well as data processing oriented both to new archaeological targets characterization and cultural heritage conservation. In this field, increasing interest has been observed in recent years in non-destructive and non-invasive geophysical test methods. They allow one to overcome the subjectivity and ambiguity arising from the number and locations of the sites chosen to perform the destructive examination. In addition, very recently, much attention has been given to the integration of the classical geophysical techniques (GPR, magnetic, ERT, IP) with new emerging surface and subsurface sensing techniques (optical sensors, lidar, microwave tomography, MASW) for a combined monitoring of archaeological constructions and artefacts. We hope that the presented research papers will be interesting for readers in the different branches of environmental and cultural heritage sciences and will attract new potential contributors to the important topics of archaeological targets recognition, cultural heritage monitoring and diagnostics. Statistically, every day several tens of significant archaeological objects are destroyed and damaged throughout the Earth, and we hope that our investigation will help to decrease these losses. We wish to thank all the authors for their presentations and fruitful discussions at the session and for preparing these articles. We are grateful to all the reviewers whose accurate and hard work has made the successful publication of this special issue possible. We also thank the editors and managers of the Journal of Geophysics and Engineering (particularly Sarah Quin) for their skilled and pleasant collaboration.

Joint Inversion of 3d Mt/gravity/magnetic at Pisagua Fault.

NASA Astrophysics Data System (ADS)

Bascur, J.; Saez, P.; Tapia, R.; Humpire, M.

2017-12-01

This work shows the results of a joint inversion at Pisagua Fault using 3D Magnetotellurics (MT), gravity and regional magnetic data. The MT survey has a poor coverage of study area with only 21 stations; however, it allows to detect a low resistivity zone aligned with the Pisagua Fault trace that it is interpreted as a damage zone. The integration of gravity and magnetic data, which have more dense sampling and coverage, adds more detail and resolution to the detected low resistivity structure and helps to improve the structure interpretation using the resulted models (density, magnetic-susceptibility and electrical resistivity). The joint inversion process minimizes a multiple target function which includes the data misfit, model roughness and coupling norms (crossgradient and direct relations) for all geophysical methods considered (MT, gravity and magnetic). This process is solved iteratively using the Gauss-Newton method which updates the model of each geophysical method improving its individual data misfit, model roughness and the coupling with the other geophysical models. For solving the model updates of magnetic and gravity methods were developed dedicated 3D inversion software codes which include the coupling norms with additionals geophysical parameters. The model update of the 3D MT is calculated using an iterative method which sequentially filters the priority model and the output model of a single 3D MT inversion process for obtaining the resistivity model coupled solution with the gravity and magnetic methods.

NASA/MSFC FY-85 Atmospheric Processes Research Review

NASA Technical Reports Server (NTRS)

Vaughan, W. W. (Compiler); Porter, F. (Compiler)

1985-01-01

The two main areas of focus for the research program are global scale processes and mesoscale processes. Geophysical fluid processes, satellite doppler lidar, satellite data analysis, atmospheric electricity, doppler lidar wind research, and mesoscale modeling are among the topics covered.

Impact of infrasound atmospheric noise on gravity detectors used for astrophysical and geophysical applications

NASA Astrophysics Data System (ADS)

Fiorucci, Donatella; Harms, Jan; Barsuglia, Matteo; Fiori, Irene; Paoletti, Federico

2018-03-01

Density changes in the atmosphere produce a fluctuating gravity field that affects gravity strainmeters or gravity gradiometers used for the detection of gravitational waves and for geophysical applications. This work addresses the impact of the atmospheric local gravity noise on such detectors, extending previous analyses. In particular we present the effect introduced by the building housing the detectors, and we analyze local gravity-noise suppression by constructing the detector underground. We present also new sound spectra and correlation measurements. The results obtained are important for the design of future gravitational-wave detectors and gravity gradiometers used to detect prompt gravity perturbations from earthquakes.

Solid earth geophysics: Data services

NASA Astrophysics Data System (ADS)

1987-01-01

The National Oceanic and Atmospheric Administration (NOAA) collects, manages, and disseminates many kinds of scientific data that result from the inquiry into the environment. The National Geophysical Data Center (NGDC), one of the several data-management centers of NOAA, is responsible for data activities in the fields of seismology, gravity, topography, geomagnetism, geothermics, marine geology and geophysics, and solar-terrestrial physics. The pamphlet briefly describes the principal products and services NGDC provides through its Solid Earth (SEG) division. Among the most important activities of SEG are acquiring and archiving data, processing and formatting data into standard sets, developing useful data products for customers, and advertising and disseminating data to the scientific, academic, and industrial communities.

Envision: An interactive system for the management and visualization of large geophysical data sets

NASA Technical Reports Server (NTRS)

Searight, K. R.; Wojtowicz, D. P.; Walsh, J. E.; Pathi, S.; Bowman, K. P.; Wilhelmson, R. B.

1995-01-01

Envision is a software project at the University of Illinois and Texas A&M, funded by NASA's Applied Information Systems Research Project. It provides researchers in the geophysical sciences convenient ways to manage, browse, and visualize large observed or model data sets. Envision integrates data management, analysis, and visualization of geophysical data in an interactive environment. It employs commonly used standards in data formats, operating systems, networking, and graphics. It also attempts, wherever possible, to integrate with existing scientific visualization and analysis software. Envision has an easy-to-use graphical interface, distributed process components, and an extensible design. It is a public domain package, freely available to the scientific community.

Using Self Potential and Multiphase Flow Modeling to Optimize Groundwater Pumping

NASA Astrophysics Data System (ADS)

Gasperikova, E.; Zhang, Y.; Hubbard, S.

2008-12-01

Numerical and field hydrological and geophysical studies have been conducted to investigate the impact of groundwater pumping on near-river hydrology for a segment of the Russian River at the Wohler Site, California, which is a riverbed filtration system managed by the Sonoma County Water Agency. Groundwater pumping near streams can cause a creation of unsaturated regions and hence reduce the pumping capacity and change the flow paths. A three-dimensional multiphase flow and transport model can be calibrated to the temperature, and water levels at monitoring wells based on known pumping rates, and the river stage. Streaming (self) potential (SP) is one of the electrokinetic processes that describes the coupled behavior of hydraulic and electrical flow within a porous medium, and is easily measured on the surface or in boreholes. Observing temporal and spatial variations in geophysical signatures provides a powerful approach for monitoring changes in the natural systems due to natural or forced (pumping) system perturbations. Geophysical and hydrological data were collected before, during and after a pumping experiment at the Wohler Site. Using this monitoring dataset, we illustrate how loose coupling between hydrogeological and geophysical (SP) processes and data can be used to calibrate the flow model and to optimize pumping schedules as needed to guide sustainable water resource development.

Electrical characterization of non‐Fickian transport in groundwater and hyporheic systems

USGS Publications Warehouse

Singha, Kamini; Pidlisecky, Adam; Day-Lewis, Frederick D.; Gooseff, Michael N.

2008-01-01

Recent work indicates that processes controlling solute mass transfer between mobile and less mobile domains in porous media may be quantified by combining electrical geophysical methods and electrically conductive tracers. Whereas direct geochemical measurements of solute preferentially sample the mobile domain, electrical geophysical methods are sensitive to changes in bulk electrical conductivity (bulk EC) and therefore sample EC in both the mobile and immobile domains. Consequently, the conductivity difference between direct geochemical samples and remotely sensed electrical geophysical measurements may provide an indication of mass transfer rates and mobile and immobile porosities in situ. Here we present (1) an overview of a theoretical framework for determining parameters controlling mass transfer with electrical resistivity in situ; (2) a review of a case study estimating mass transfer processes in a pilot‐scale aquifer storage recovery test; and (3) an example application of this method for estimating mass transfer in watershed settings between streams and the hyporheic corridor. We demonstrate that numerical simulations of electrical resistivity studies of the stream/hyporheic boundary can help constrain volumes and rates of mobile‐immobile mass transfer. We conclude with directions for future research applying electrical geophysics to understand field‐scale transport in aquifer and fluvial systems subject to rate‐limited mass transfer.

An efficient sequential strategy for realizing cross-gradient joint inversion: method and its application to 2-D cross borehole seismic traveltime and DC resistivity tomography

NASA Astrophysics Data System (ADS)

Gao, Ji; Zhang, Haijiang

2018-05-01

Cross-gradient joint inversion that enforces structural similarity between different models has been widely utilized in jointly inverting different geophysical data types. However, it is a challenge to combine different geophysical inversion systems with the cross-gradient structural constraint into one joint inversion system because they may differ greatly in the model representation, forward modelling and inversion algorithm. Here we propose a new joint inversion strategy that can avoid this issue. Different models are separately inverted using the existing inversion packages and model structure similarity is only enforced through cross-gradient minimization between two models after each iteration. Although the data fitting and structural similarity enforcing processes are decoupled, our proposed strategy is still able to choose appropriate models to balance the trade-off between geophysical data fitting and structural similarity. This is realized by using model perturbations from separate data inversions to constrain the cross-gradient minimization process. We have tested this new strategy on 2-D cross borehole synthetic seismic traveltime and DC resistivity data sets. Compared to separate geophysical inversions, our proposed joint inversion strategy fits the separate data sets at comparable levels while at the same time resulting in a higher structural similarity between the velocity and resistivity models.

Hydro-geophysical observations integration in numerical model: case study in Mediterranean karstic unsaturated zone (Larzac, france)

NASA Astrophysics Data System (ADS)

Champollion, Cédric; Fores, Benjamin; Le Moigne, Nicolas; Chéry, Jean

2016-04-01

Karstic hydro-systems are highly non-linear and heterogeneous but one of the main water resource in the Mediterranean area. Neither local measurements in boreholes or analysis at the spring can take into account the variability of the water storage. Since a few years, ground-based geophysical measurements (such as gravity, electrical resistivity or seismological data) allows following water storage in heterogeneous hydrosystems at an intermediate scale between boreholes and basin. Behind classical rigorous monitoring, the integration of geophysical data in hydrological numerical models in needed for both processes interpretation and quantification. Since a few years, a karstic geophysical observatory (GEK: Géodésie de l'Environnement Karstique, OSU OREME, SNO H+) has been setup in the Mediterranean area in the south of France. The observatory is surrounding more than 250m karstified dolomite, with an unsaturated zone of ~150m thickness. At the observatory water level in boreholes, evapotranspiration and rainfall are classical hydro-meteorological observations completed by continuous gravity, resistivity and seismological measurements. The main objective of the study is the modelling of the whole observation dataset by explicit unsaturated numerical model in one dimension. Hydrus software is used for the explicit modelling of the water storage and transfer and links the different observations (geophysics, water level, evapotranspiration) with the water saturation. Unknown hydrological parameters (permeability, porosity) are retrieved from stochastic inversions. The scale of investigation of the different observations are discussed thank to the modelling results. A sensibility study of the measurements against the model is done and key hydro-geological processes of the site are presented.

AfricaArray International Geophysics Field School: Applications of Near Surface Geophysics to challenges encountered in mine planning

NASA Astrophysics Data System (ADS)

Webb, S. J.; Jones, M. Q.; Durrheim, R. J.; Nyblade, A.; Snyman, Q.

2012-12-01

Hard rock exploration and mining presents many opportunities for the effective use of near surface geophysics. For over 10 years the AfricaArray international geophysics field school has been hosted at a variety of mines in South Africa. While the main objective of the field school is practical training for the next generation of geophysicists, being hosted at a mine has allowed us to investigate applications of near surface geophysics in the early stages of mine planning and development as geophysics is often cheaper and faster than drilling. Several applications include: detailed delineation of dykes and stringer dykes, physical property measurements on drill core for modeling and marker horizons, determination of overburden thickness, locations of water and faults. Dolerite dykes are usually magnetic and are associated with loss of ground (i.e. where the dyke replaces the ore and thus reduces the amount of ore available) and safety/stability concerns. Thus the accurate mapping of dykes and narrow stringers that are associated with them are crucial to the safe planning of a mine. We have acquired several case studies where ground magnetic surveys have greatly improved on the resolution and detail of airborne magnetic surveys in regions of complicated dyke swarms. In many cases, thin stringer dykes of less than 5 cm have been detected. Physical property measurements of these dykes can be used to distinguish between different ages of dykes. It is important to accurately determine overburden thickness when planning an open pit mine as this directly affects the cost of development. Depending on the nature of the overburden, both refraction seismic and or DC resistivity can provide continuous profiling in the area of interest that fills in gaps between boreholes. DC resistivity is also effective for determining water associated with dykes and structures that may affect mine planning. The field school mainly addresses the training of a variety of students. The core students are the geophysics Honours students (~4th year undergraduates). In addition, up to 8 students from all over Africa are included in the program to help address practical training in Africa. The final cohort are minority students from the USA. Participants spend a week planning and costing out surveys, a week in the field collecting data using different methods including: gravity, DGPS, magnetics, resistivity, refraction seismic, EM methods, core logging and physical property measurements. The final week is spent interpreting and integrating their results. Graduate students are given the opportunity to instruct on the field school and manage the logistics for a particular method. The field school is unique in Africa and satisfies a need for practical training with limited resources, with a rare blend of cultural interactions!

Spring Meeting Preview: Joint Assembly Sessions Focus on Urbanization

NASA Astrophysics Data System (ADS)

Zielinski, Sarah

2006-04-01

The urban environment has grown to encompass not just the downtown area of a city but also the suburbs and rapidly growing exurban areas. This growth can affect a wide range of geological, physical, and biological processes. Several sessions at the 23-26 May 2006 Joint Assembly in Baltimore, Md., will explore this topic. Two union sessions on the ``Impact of Urbanization on Environmental Systems'' (U31A and U32A) will take place on Wednesday morning, 24 May, at 8:30 A.M. and 10:45 A.M. The sessions are designed to be a wide-ranging exploration of the different, multiple roles that urbanization, and the changes in the environment that accompany urbanization, have on biological and geophysical processes, said session co-convener Larry Band. Brand is Voit Gilmore distinguished professor and chair of the department of geography at the University of North Carolina, Chapel Hill.

Using record player demonstrations as analog models for geophysical fluids

NASA Astrophysics Data System (ADS)

Grannan, A. M.; Cheng, J. S.; Hawkins, E. K.; Ribeiro, A.; Aurnou, J. M.

2015-12-01

All celestial bodies, including stars, planets, satellites, and asteroids, rotate. The influence of rotation on the fluid layers in these bodies plays an important and diverse role, affecting many processes including oceanic and atmospheric circulation at the surface and magnetic field generation occurring in the interior. To better understand these large-scale processes, record players and containers of water are used as analog models to demonstrate the basic interplay between rotation and fluid motions. To contrast between rotating and non-rotating fluid motions, coffee creamer and food coloring are used as fluid tracers to provide a hands-on method of understanding the influence of rotation on the shapes of the planets, weather patterns, and the alignment of magnetic fields with rotational axes. Such simple demonstrations have been successfully employed for children in public outreach events and for adults in graduate level fluid dynamics courses.

Geophysical Signitures From Hydrocarbon Contaminated Aquifers

NASA Astrophysics Data System (ADS)

Abbas, M.; Jardani, A.

2015-12-01

The task of delineating the contamination plumes as well as studying their impact on the soil and groundwater biogeochemical properties is needed to support the remediation efforts and plans. Geophysical methods including electrical resistivity tomography (ERT), induced polarization (IP), ground penetrating radar (GPR), and self-potential (SP) have been previously used to characterize contaminant plumes and investigate their impact on soil and groundwater properties (Atekwana et al., 2002, 2004; Benson et al., 1997; Campbell et al., 1996; Cassidy et al., 2001; Revil et al., 2003; Werkema et al., 2000). Our objective was to: estimate the hydrocarbon contamination extent in a contaminated site in northern France, and to adverse the effects of the oil spill on the groundwater properties. We aim to find a good combination of non-intrusive and low cost methods which we can use to follow the bio-remediation process, which is planned to proceed next year. We used four geophysical methods including electrical resistivity tomography, IP, GPR, and SP. The geophysical data was compared to geochemical ones obtained from 30 boreholes installed in the site during the geophysical surveys. Our results have shown: low electrical resistivity values; high chargeability values; negative SP anomalies; and attenuated GPR reflections coincident with groundwater contamination. Laboratory and field geochemical measurements have demonstrated increased groundwater electrical conductivity and increased microbial activity associated with hydrocarbon contamination of groundwater. Our study results support the conductive model suggested by studies such as Sauck (2000) and Atekwana et al., (2004), who suggest that biological alterations of hydrocarbon contamination can substantially modify the chemical and physical properties of the subsurface, producing a dramatic shift in the geo-electrical signature from resistive to conductive. The next stage of the research will include time lapse borehole and 3D geophysical measurements coupled to biological and chemical surface phase experiments in order to monitor the bioremediation processes.

The University of Texas Institute for Geophysics' Marine Geology and Geophysics Field Course: A Hand-On Education Approach to Applied Geophysics

NASA Astrophysics Data System (ADS)

Davis, M. B.; Goff, J.; Gulick, S. P. S.; Fernandez, R.; Duncan, D.; Saustrup, S.

2016-12-01

The University of Texas Institute for Geophysics, Jackson School of Geosciences, offers a 3-week marine geology and geophysics field course. The course provides hands-on instruction and training for graduate and upper-level undergraduate students in high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, and sediment sampling and analysis. Students first participate in 3 days of classroom instruction designed to communicate geological context of the field area along with theoretical and technical background on each field method. The class then travels to the Gulf Coast for a week of at-sea field work at locations that provide an opportunity to investigate coastal and continental shelf processes. Teams of students rotate between UTIG's 26' R/V Scott Petty and NOAA's 82' R/V Manta. They assist with survey design, instrumentation set up, and learn about acquisition, quality control, and safe instrument deployment. Teams also process data and analyze samples in onshore field labs. During the final week teams integrate, interpret, and visualize data in a final project using industry-standard software. The course concludes with team presentations on their interpretations with academic and industry supporters. Students report a greater understanding of marine geology and geophysics through the course's intensive, hands-on, team approach and high instructor/student ratio (sixteen students, three faculty, and three teaching assistants). Post-class, students may incorporate course data in senior honors or graduate thesis and are encouraged to publish and present results at national meetings. This course (to our knowledge) remains the only one of its kind, satisfies field experience requirements for some degree programs, and provides an alternative to land-based field courses. Alumni note the course's applicability to energy, environmental, and geotechnical industries as well as coastal restoration/management fields.

50 CFR 37.53 - Submission of data and information.

Code of Federal Regulations, 2011 CFR

2011-10-01

... processing. (c) Processed geophysical information shall be submitted with extraneous signals and interference... of data gathering or utilization, i.e., acquisition, processing, reprocessing, analysis, and... survey conducted under the permittee's permit, including digital navigational data, if obtained, and...

50 CFR 37.53 - Submission of data and information.

Code of Federal Regulations, 2010 CFR

2010-10-01

... processing. (c) Processed geophysical information shall be submitted with extraneous signals and interference... of data gathering or utilization, i.e., acquisition, processing, reprocessing, analysis, and... survey conducted under the permittee's permit, including digital navigational data, if obtained, and...

50 CFR 37.53 - Submission of data and information.

Code of Federal Regulations, 2012 CFR

2012-10-01

... processing. (c) Processed geophysical information shall be submitted with extraneous signals and interference... of data gathering or utilization, i.e., acquisition, processing, reprocessing, analysis, and... survey conducted under the permittee's permit, including digital navigational data, if obtained, and...

50 CFR 37.53 - Submission of data and information.

Code of Federal Regulations, 2014 CFR

2014-10-01

... processing. (c) Processed geophysical information shall be submitted with extraneous signals and interference... of data gathering or utilization, i.e., acquisition, processing, reprocessing, analysis, and... survey conducted under the permittee's permit, including digital navigational data, if obtained, and...

50 CFR 37.53 - Submission of data and information.

Code of Federal Regulations, 2013 CFR

2013-10-01

... processing. (c) Processed geophysical information shall be submitted with extraneous signals and interference... of data gathering or utilization, i.e., acquisition, processing, reprocessing, analysis, and... survey conducted under the permittee's permit, including digital navigational data, if obtained, and...

Nonlinear inversion of potential-field data using a hybrid-encoding genetic algorithm

USGS Publications Warehouse

Chen, C.; Xia, J.; Liu, J.; Feng, G.

2006-01-01

Using a genetic algorithm to solve an inverse problem of complex nonlinear geophysical equations is advantageous because it does not require computer gradients of models or "good" initial models. The multi-point search of a genetic algorithm makes it easier to find the globally optimal solution while avoiding falling into a local extremum. As is the case in other optimization approaches, the search efficiency for a genetic algorithm is vital in finding desired solutions successfully in a multi-dimensional model space. A binary-encoding genetic algorithm is hardly ever used to resolve an optimization problem such as a simple geophysical inversion with only three unknowns. The encoding mechanism, genetic operators, and population size of the genetic algorithm greatly affect search processes in the evolution. It is clear that improved operators and proper population size promote the convergence. Nevertheless, not all genetic operations perform perfectly while searching under either a uniform binary or a decimal encoding system. With the binary encoding mechanism, the crossover scheme may produce more new individuals than with the decimal encoding. On the other hand, the mutation scheme in a decimal encoding system will create new genes larger in scope than those in the binary encoding. This paper discusses approaches of exploiting the search potential of genetic operations in the two encoding systems and presents an approach with a hybrid-encoding mechanism, multi-point crossover, and dynamic population size for geophysical inversion. We present a method that is based on the routine in which the mutation operation is conducted in the decimal code and multi-point crossover operation in the binary code. The mix-encoding algorithm is called the hybrid-encoding genetic algorithm (HEGA). HEGA provides better genes with a higher probability by a mutation operator and improves genetic algorithms in resolving complicated geophysical inverse problems. Another significant result is that final solution is determined by the average model derived from multiple trials instead of one computation due to the randomness in a genetic algorithm procedure. These advantages were demonstrated by synthetic and real-world examples of inversion of potential-field data. ?? 2005 Elsevier Ltd. All rights reserved.

Electromagnetic forward modelling for realistic Earth models using unstructured tetrahedral meshes and a meshfree approach

NASA Astrophysics Data System (ADS)

Farquharson, C.; Long, J.; Lu, X.; Lelievre, P. G.

2017-12-01

Real-life geology is complex, and so, even when allowing for the diffusive, low resolution nature of geophysical electromagnetic methods, we need Earth models that can accurately represent this complexity when modelling and inverting electromagnetic data. This is particularly the case for the scales, detail and conductivity contrasts involved in mineral and hydrocarbon exploration and development, but also for the larger scale of lithospheric studies. Unstructured tetrahedral meshes provide a flexible means of discretizing a general, arbitrary Earth model. This is important when wanting to integrate a geophysical Earth model with a geological Earth model parameterized in terms of surfaces. Finite-element and finite-volume methods can be derived for computing the electric and magnetic fields in a model parameterized using an unstructured tetrahedral mesh. A number of such variants have been proposed and have proven successful. However, the efficiency and accuracy of these methods can be affected by the "quality" of the tetrahedral discretization, that is, how many of the tetrahedral cells in the mesh are long, narrow and pointy. This is particularly the case if one wants to use an iterative technique to solve the resulting linear system of equations. One approach to deal with this issue is to develop sophisticated model and mesh building and manipulation capabilities in order to ensure that any mesh built from geological information is of sufficient quality for the electromagnetic modelling. Another approach is to investigate other methods of synthesizing the electromagnetic fields. One such example is a "meshfree" approach in which the electromagnetic fields are synthesized using a mesh that is distinct from the mesh used to parameterized the Earth model. There are then two meshes, one describing the Earth model and one used for the numerical mathematics of computing the fields. This means that there are no longer any quality requirements on the model mesh, which makes the process of building a geophysical Earth model from a geological model much simpler. In this presentation we will explore the issues that arise when working with realistic Earth models and when synthesizing geophysical electromagnetic data for them. We briefly consider meshfree methods as a possible means of alleviating some of these issues.

Potential-Field Geophysical Software for the PC

USGS Publications Warehouse

,

1995-01-01

The computer programs of the Potential-Field Software Package run under the DOS operating system on IBM-compatible personal computers. They are used for the processing, display, and interpretation of potential-field geophysical data (gravity- and magnetic-field measurements) and other data sets that can be represented as grids or profiles. These programs have been developed on a variety of computer systems over a period of 25 years by the U.S. Geological Survey.

Deep Europe today: Geophysical synthesis of the upper mantle structure and lithospheric processes over 3.5 Ga

USGS Publications Warehouse

Artemieva, I.M.; Thybo, H.; Kaban, M.K.; ,

2006-01-01

We present a summary of geophysical models of the subcrustal lithosphere of Europe. This includes the results from seismic (reflection and refraction profiles, P- and S-wave tomography, mantle anisotropy), gravity, thermal, electromagnetic, elastic and petrological studies of the lithospheric mantle. We discuss major tectonic processes as reflected in the lithospheric structure of Europe, from Precambrian terrane accretion and subduction to Phanerozoic rifting, volcanism, subduction and continent-continent collision. The differences in the lithospheric structure of Precambrian and Phanerozoic Europe, as illustrated by a comparative analysis of different geophysical data, are shown to have both a compositional and a thermal origin. We propose an integrated model of physical properties of the European subcrustal lithosphere, with emphasis on the depth intervals around 150 and 250 km. At these depths, seismic velocity models, constrained by body-and surface-wave continent-scale tomography, are compared with mantle temperatures and mantle gravity anomalies. This comparison provides a framework for discussion of the physical or chemical origin of the major lithospheric anomalies and their relation to large-scale tectonic processes, which have formed the present lithosphere of Europe. ?? The Geological Society of London 2006.

Comparison of the Tangent Linear Properties of Tracer Transport Schemes Applied to Geophysical Problems.

NASA Technical Reports Server (NTRS)

Kent, James; Holdaway, Daniel

2015-01-01

A number of geophysical applications require the use of the linearized version of the full model. One such example is in numerical weather prediction, where the tangent linear and adjoint versions of the atmospheric model are required for the 4DVAR inverse problem. The part of the model that represents the resolved scale processes of the atmosphere is known as the dynamical core. Advection, or transport, is performed by the dynamical core. It is a central process in many geophysical applications and is a process that often has a quasi-linear underlying behavior. However, over the decades since the advent of numerical modelling, significant effort has gone into developing many flavors of high-order, shape preserving, nonoscillatory, positive definite advection schemes. These schemes are excellent in terms of transporting the quantities of interest in the dynamical core, but they introduce nonlinearity through the use of nonlinear limiters. The linearity of the transport schemes used in Goddard Earth Observing System version 5 (GEOS-5), as well as a number of other schemes, is analyzed using a simple 1D setup. The linearized version of GEOS-5 is then tested using a linear third order scheme in the tangent linear version.

Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods

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

Keating, Kristina; Slater, Lee; Ntarlagiannis, Dimitris

2015-02-24

This documents contains the final report for the project "Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods" (DE-SC0007049) Executive Summary: Our research aimed to develop borehole measurement techniques capable of monitoring subsurface processes, such as changes in pore geometry and iron/sulfur geochemistry, associated with remediation of heavy metals and radionuclides. Previous work has demonstrated that geophysical method spectral induced polarization (SIP) can be used to assess subsurface contaminant remediation; however, SIP signals can be generated from multiple sources limiting their interpretation value. Integrating multiple geophysical methods, such as nuclear magnetic resonance (NMR)more » and magnetic susceptibility (MS), with SIP, could reduce the ambiguity of interpretation that might result from a single method. Our research efforts entails combining measurements from these methods, each sensitive to different mineral forms and/or mineral-fluid interfaces, providing better constraints on changes in subsurface biogeochemical processes and pore geometries significantly improving our understanding of processes impacting contaminant remediation. The Rifle Integrated Field Research Challenge (IFRC) site was used as a test location for our measurements. The Rifle IFRC site is located at a former uranium ore-processing facility in Rifle, Colorado. Leachate from spent mill tailings has resulted in residual uranium contamination of both groundwater and sediments within the local aquifer. Studies at the site include an ongoing acetate amendment strategy, native microbial populations are stimulated by introduction of carbon intended to alter redox conditions and immobilize uranium. To test the geophysical methods in the field, NMR and MS logging measurements were collected before, during, and after acetate amendment. Next, laboratory NMR, MS, and SIP measurements were collected on columns of Rifle sediments during acetate amendment. The laboratory experiments were designed to simulate the field experiments; changes in geophysical signals were expected to correlate with changes in redox conditions and iron speciation. Field MS logging measurements revealed vertically stratified magnetic mineralization, likely the result of detrital magnetic fraction within the bulk alluvium. Little to no change was observed in the MS data suggesting negligible production of magnetic phases (e.g. magnetite, pyrrhotite) as a result of sulfidogenesis. Borehole NMR measurements contained high levels of noise contamination requiring significant signal processing, and analysis suggests that any changes may be difficult to differentiate from simultaneous changes in water content. Laboratory MS and NMR measurements remained relatively stable throughout the course of the acetate amendment experiment, consistent with field measurements. However, SIP measurements changed during the acetate amendment associated with the formation of iron-sulfide mineral phases; a finding that is consistent with chemical analysis of the solid phase materials in the columns.« less

Joint geophysical measurements to investigate the Rossano of Vaglio archaeological site affected by landslide phenomena (Basilicata region, Southern Italy)

NASA Astrophysics Data System (ADS)

Perrone, A.; Chianese, D.; Lapenna, V.; Lorenzo, P.; Piscitelli, S.; Rizzo, E.; Sdao, F.

2003-04-01

In the frame of a project supported by the Italian Ministry of Research: "Geomorphological study and landslides control in some areas of the Basilicata region characterized by historical-cultural heritage", the I.M.A.A. of the CNR (Tito Scalo, Potenza) and the Di.S.G.G. of the Basilicata University, developed a research activity focussed on the realization of combined geophysical measurements for the study of archaeological areas affected by landslide phenomena in Basilicata region (Southern Italy). Since IV century b.C., the birth and the evolution of many religious places is observed in the Basilicata region. Location and construction of these sanctuaries were influenced by the geological and geomorphological setting: many of them were built near important springs; others on morphological terraces, representing the main effect of the large and ancient landslides, often reactivated during the years. In this work we report the results regarding the application of 2D electrical resistivity tomographies, electromagnetic and magnetic measurements carried out in the Rossano of Vaglio (Potenza, Italy), where in the late IV century b.C. raised a sanctuary devoted to the Mephitis goddess (Adamasteanu and Dilthey, 1992; Masseria and D'Anisi, 2001). The sacred area was affected by a multiple and retrogressive rototranslational slide, historically and actually subject to reactivation. The geophysical results, obtained combining advanced technologies for data acquisition and new methods for data inversion (Loke and Barker, 1996; Ciminale and Loddo, 2001; Nuzzo et al, 2002), allowed us to define the geometrical characteristics of the landslide body, to outline the sliding surfaces and to individuate the buried structures of the sanctuary.

Recent Improvements in AMSR2 Ground-Based RFI Filtering

NASA Astrophysics Data System (ADS)

Scott, J. P.; Gentemann, C. L.; Wentz, F. J.

2015-12-01

Passive satellite radiometer measurements in the microwave frequencies (6-89 GHz) are useful in providing geophysical retrievals of sea surface temperature (SST), atmospheric water vapor, wind speed, rain rate, and more. However, radio frequency interference (RFI) is one of the fastest growing sources of error in these retrievals. RFI can originate from broadcasting satellites, as well as from ground-based instrumentation that makes use of the microwave range. The microwave channel bandwidths used by passive satellite radiometers are often wider than the protected bands allocated for this type of remote sensing, a common practice in microwave radiometer design used to reduce the effect of instrument noise in the observed signal. However, broad channel bandwidths allow greater opportunity for RFI to affect these observations and retrievals. For ground-based RFI, a signal is broadcast directly into the atmosphere which may interfere with the radiometer - its antenna, cold mirror, hot load or the internal workings of the radiometer itself. It is relatively easy to identify and flag RFI from large sources, but more difficult to do so from small, sporadic sources. Ground-based RFI has high spatial and temporal variability, requiring constant, automated detection and removal to avoid spurious trends leaching into the geophysical retrievals. Ascension Island in the South Atlantic Ocean has been one of these notorious ground-based RFI sources, affecting many microwave radiometers, including the AMSR2 radiometer onboard JAXA's GCOM-W1 satellite. Ascension Island RFI mainly affects AMSR2's lower frequency channels (6.9, 7.3, and 10.65 GHz) over a broad spatial region in the South Atlantic Ocean, which makes it challenging to detect and flag this RFI using conventional channel and geophysical retrieval differencing techniques. The authors have developed a new method of using the radiometer's earth counts and hot counts, for the affected channels, to detect an Ascension Island RFI event and flag the data efficiently and accurately, thereby reducing false detections and optimizing retrieval quality and data preservation.

The Geysers-Clear Lake geothermal area, California - an updated geophysical perspective of heat sources

USGS Publications Warehouse

Stanley, W.D.; Blakely, R.J.

1995-01-01

The Geysers-Clear Lake geothermal area encompasses a large dry-steam production area in The Geysers field and a documented high-temperature, high-pressure, water-dominated system in the area largely south of Clear Lake, which has not been developed. An updated view is presented of the geological/geophysical complexities of the crust in this region in order to address key unanswered questions about the heat source and tectonics. Forward modeling, multidimensional inversions, and ideal body analysis of the gravity data, new electromagnetic sounding models, and arguments made from other geophysical data sets suggest that many of the geophysical anomalies have significant contributions from rock property and physical state variations in the upper 7 km and not from "magma' at greater depths. Regional tectonic and magmatic processes are analyzed to develop an updated scenario for pluton emplacement that differs substantially from earlier interpretations. In addition, a rationale is outlined for future exploration for geothermal resources in The Geysers-Clear Lake area. -from Authors

``Recycling'' Geophysics: Monitoring and Isotopic Analysis of Engineered Biological Systems

NASA Astrophysics Data System (ADS)

Doherty, R.; Singh, K. P.; Ogle, N.; Ntarlagiannis, D.

2010-12-01

The emerging sub discipline of biogeophysics has provoked debate on the mechanisms of microbial processes that may contribute to geophysical signatures. At field scales geophysical signatures are often non unique due to the many parameters (physical, chemical, and biological) that are involved. It may be easier to apply geophysical techniques such as electrodic potential (EP), self potential (SP) and induced polarization (IP) to engineered biological systems where there is a degree of control over the design of the physical and chemical domain. Here we present results of a column experiment that was designed to anaerobically biodegrade dissolved organic matter in landfill leachate. The column utilises a recycled porous media (concrete) to help sequester organic carbon. Electrodic potential, self potential and induced polarisation are used in conjunction with chemical and isotopic techniques to monitor the effectiveness of this approach. Preliminary carbon and oxygen isotopic analysis on concrete from the column in contact with leachate show isotopic enrichment suggesting abiotic precipitation of carbonates.

Towards a geophysical decision-support system for monitoring and managing unstable slopes

NASA Astrophysics Data System (ADS)

Chambers, J. E.; Meldrum, P.; Wilkinson, P. B.; Uhlemann, S.; Swift, R. T.; Inauen, C.; Gunn, D.; Kuras, O.; Whiteley, J.; Kendall, J. M.

2017-12-01

Conventional approaches for condition monitoring, such as walk over surveys, remote sensing or intrusive sampling, are often inadequate for predicting instabilities in natural and engineered slopes. Surface observations cannot detect the subsurface precursors to failure events; instead they can only identify failure once it has begun. On the other hand, intrusive investigations using boreholes only sample a very small volume of ground and hence small scale deterioration process in heterogeneous ground conditions can easily be missed. It is increasingly being recognised that geophysical techniques can complement conventional approaches by providing spatial subsurface information. Here we describe the development and testing of a new geophysical slope monitoring system. It is built around low-cost electrical resistivity tomography instrumentation, combined with integrated geotechnical logging capability, and coupled with data telemetry. An automated data processing and analysis workflow is being developed to streamline information delivery. The development of this approach has provided the basis of a decision-support tool for monitoring and managing unstable slopes. The hardware component of the system has been operational at a number of field sites associated with a range of natural and engineered slopes for up to two years. We report on the monitoring results from these sites, discuss the practicalities of installing and maintaining long-term geophysical monitoring infrastructure, and consider the requirements of a fully automated data processing and analysis workflow. We propose that the result of this development work is a practical decision-support tool that can provide near-real-time information relating to the internal condition of problematic slopes.

Distributed visualization of gridded geophysical data: the Carbon Data Explorer, version 0.2.3

NASA Astrophysics Data System (ADS)

Endsley, K. A.; Billmire, M. G.

2016-01-01

Due to the proliferation of geophysical models, particularly climate models, the increasing resolution of their spatiotemporal estimates of Earth system processes, and the desire to easily share results with collaborators, there is a genuine need for tools to manage, aggregate, visualize, and share data sets. We present a new, web-based software tool - the Carbon Data Explorer - that provides these capabilities for gridded geophysical data sets. While originally developed for visualizing carbon flux, this tool can accommodate any time-varying, spatially explicit scientific data set, particularly NASA Earth system science level III products. In addition, the tool's open-source licensing and web presence facilitate distributed scientific visualization, comparison with other data sets and uncertainty estimates, and data publishing and distribution.

Geophysical Investigations in the Caucasus (1925 - 2012): Initial, Basic and Modern Stages

NASA Astrophysics Data System (ADS)

Eppelbaum, L. V.

2012-04-01

The Caucasian Mountains occupy an area of about 440,000 km2. A number of important mineral resources are concentrated there. Geophysical data on the geological structure of Caucasus can shed light on the basic principles of evolution of the Earth, the distribution of minerals and seismic activity. However, geophysical surveys under complex conditions are generally riddled by poor accessibility to certain mountainous regions, the unevenness of observation surfaces, as well as by a great variety and frequent changes of tectonic structures and geological bodies with variable physical properties. These factors either restrict geophysical surveys in difficult environments or confine the scope of useful information drawn from the results obtained. This has led to the development of special techniques in geophysical surveys, data processing and interpretation that draws heavily on the experience accumulated in the specific conditions of these mountainous regions. First applied geophysical observations in the Caucasus region - thermal measurements in boreholes - were carried out by Bazevich (1881) in the Absheron Peninsula. At the same time, start of the initial stage is usually referred to as the mid 20-s of the XX century, when the rare, but systematic geophysical observations (mainly gravity and magnetic) were begun in some Caucasian areas. Somewhat later began to apply the resistivity method. Mid 30-s is characterized by the beginning of application of borehole geophysics and seismic prospecting. The marine seismics firstly in the former Soviet Union was tested in the Caspian Sea. In general, the initial stage is characterized by slow, but steady rise (except during World War II) lasted until 1960. A basic stage (1960-1991) is characterized by very intensive employment of geophysical methods (apparently, any possible geophysical methods were tested in this region). At this time the Caucasus region is considered in the former Soviet Union as a geophysical polygon for testing different geophysical methods and methodologies in complicated environments. Airborne magnetic and gravity surveys covered all the Caucasus, regional seismic and magnetotelluric studies were used as reference profiles for deep structure investigation. Numerous effective applications of geophysical methods for searching ore, oil&gas deposits, building raw, fresh water localization, solving engineering, etc. was demonstrated. Seismological investigations (including different methods) were widely applied throughout the entire Caucasian region. Satellite geophysical examinations were successfully combined with other methods. Finally, destruction of the former Soviet Union in 1991 (beginning of the modern stage) caused a sharp common decreasing of the geophysical activity in this region. Only foreign oil-&gas companies (mainly American and England) demonstrated some industrial geophysical activity basically in the Caspian Sea. In the last few years the situation began to straighten out, especially in the field of seismology. This presentation is based of the author's experience (e.g., Eppelbaum, 1989, 1991, 2009; Eppelbaum et al., 1987; Eppelbaum and Finkelstein, 1998; Eppelbaum and Khesin, 1988, 1992, 2002, 2004, 2011, 2012; Eppelbaum and Mishne, 2011; Eppelbaum et al., 2003, 2004; Khesin et al., 1988, 1993a, 1993b, 1996, 1997; Khesin and Eppelbaum, 1986, 1994, 1997, 2007; Pilchin and Eppelbaum, 1997, 2011) and corresponding publications and reviews of other authors.

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.

GPR survey, as one of the best geophysical methods for social and industrial needs

NASA Astrophysics Data System (ADS)

Chernov, Anatolii

2016-04-01

This paper is about ways and methods of applying non-invasive geophysical method - Ground penetrating radar (GPR) survey in different spheres of science, industry, social life and culture. Author would like to show that geological methods could be widely used for solving great variety of industrial, human safety and other problems. In that article, we take GPR survey as an example of such useful geophysical methods. It is a fact that investigation of near surface underground medium is important process, which influence on development of different spheres of science and social life: investigation of near surface geology (layering, spreading of rock types, identification of voids, etc.), hydrogeology (depth to water horizons, their thickness), preparation step for construction of roads and buildings (civil geology, engineering geology), investigation of cultural heritage (burial places, building remains,...), ecological investigations (land slides, variation in underground water level, etc.), glaciology. These tasks can be solved by geological methods, but as usual, geophysical survey takes a lot of time and energy (especially electric current and resistivity methods, seismic survey). Author claims that GPR survey can be performed faster than other geophysical surveys and results of GPR survey are informative enough to make proper conclusions. Some problems even cannot be solved without GPR. For example, identification of burial place (one of author's research objects): results of magnetic and electric resistivity tomography survey do not contain enough information to identify burial place, but according to anomalies on GPR survey radarograms, presence of burial place can be proven. Identification of voids and non-magnetic objects also hardly can be done by another non-invasive geophysics surveys and GPR is applicable for that purpose. GPR can be applied for monitoring of dangerous processes in geological medium under roads, buildings, parks and other places of human activity. Monitoring of such hazards as landslides, underground erosion, variation in ground water level can help prevent dangerous processes with destructive consequences, which can result in peoples' injuries and even death. Moreover, GPR can be used in other spheres of life, where investigation of hidden (under or behind conductive for electromagnetic wave material) objects is needed: rescue operations (finding of people after natural and human-made disasters under snow, under debris of building material); military purpose (security systems, identification of people presence through walls, doors, ground etc.). Author work on algorithms (first of all for VIY GPRs (http://viy.ua/)), which will help more precisely find objects of interest on radarograms and even solve inverse problem of geophysics. According to information in that article, geophysical methods can be widely used to solve great variety of tasks and help to investigate humans' past (researches of cultural heritage) and provide information to create safe and comfortable future (preventing of natural hazards and better planning of construction).

Description of algorithms for processing Coastal Zone Color Scanner (CZCS) data

NASA Technical Reports Server (NTRS)

Zion, P. M.

1983-01-01

The algorithms for processing coastal zone color scanner (CZCS) data to geophysical units (pigment concentration) are described. Current public domain information for processing these data is summarized. Calibration, atmospheric correction, and bio-optical algorithms are presented. Three CZCS data processing implementations are compared.

Using remote sensing to monitor past changes and assess future scenarios for the Sacramento-San Joaquin River Delta waterways, California USA

NASA Astrophysics Data System (ADS)

Santos, Maria J.; Hestir, Erin; Khanna, Shruti; Ustin, Susan L.

2017-04-01

Historically, deltas have been extensively affected both by natural processes and human intervention. Thus, understanding drivers, predicting impacts and optimizing solutions to delta problems requires a holistic approach spanning many sectors, disciplines and fields of expertise. Deltas are ideal model systems to understand the effects of the interaction between social and ecological domains, as they face unprecedented disturbances and threats to their biological and ecological sustainability. The challenge for deltas is to meet the goals of supporting biodiversity and ecosystem processes while also provisioning fresh water resources for human use. We provide an overview of the last 150 years of the Sacramento-San Joaquin River delta, where we illustrate the parallel process of an increase in disturbances, by particularly zooming in on the current cascading effects of invasive species on geophysical and biological processes. Using remote sensing data coupled with in situ measurements of water quality, turbidity, and species presence we show how the spread and persistence of aquatic invasive species affects sedimentation processes and ecosystem functioning. Our results show that the interactions between the biological and physical conditions in the Delta affect the trajectory of dominance by native and invasive aquatic plant species. Trends in growth and community characteristics associated with predicted impacts of climate change (sea level rise, warmer temperatures, changes in the hydrograph with high winter and low summer outflows) do not provide simple predictions. Individually, the impact of specific environmental changes on the biological components can be predicted, however it is the complex interactions of biological communities with the suite of physical changes that make predictions uncertain. Systematic monitoring is critical to provide the data needed to document and understand change of these delta systems, and to identify successful adaptation strategies.

Use of Geodetic Surveys of Leveling Lines and Dry Tilt Arrays to Study Faults and Volcanoes in Undergraduate Field Geophysics Classes

NASA Astrophysics Data System (ADS)

Polet, J.; Alvarez, K.; Elizondo, K.

2017-12-01

In the early 1980's and 1990's numerous leveling lines and dry tilt arrays were installed throughout Central and Southern California by United States Geological Survey scientists and other researchers (e.g. Sylvester, 1985). These lines or triangular arrays of geodetic monuments commonly straddle faults or have been installed close to volcanic areas, where significant motion is expected over relatively short time periods. Over the past year, we have incorporated geodetic surveys of these arrays as part of our field exercises in undergraduate and graduate level classes on topics such as shallow subsurface geophysics and field geophysics. In some cases, the monuments themselves first had to be located based on only limited information, testing students' Brunton use and map reading skills. Monuments were then surveyed using total stations and global navigation satellite system (GNSS) receivers, using a variety of experimental procedures. The surveys were documented with tables, photos, maps and graphs in field reports, as well as in wiki pages created by student groups for a geophysics field class this June. The measurements were processed by the students and compared with similar data from surveys conducted soon after installation of the arrays, to analyze the deformation that occurred over the last few decades. The different geodetic techniques were also compared and an error analysis was conducted. The analysis and processing of these data challenged and enhanced students' quantitative literacy and technology skills. The final geodetic measurements are being incorporated into several senior and MSc thesis projects. Further surveys are planned for additional classes, in topics that could include seismology, geodesy, volcanology and global geophysics. We are also considering additional technologies, such as structure from motion (SfM) photogrammetry.

Tackling some of the most intricate geophysical challenges via high-performance computing

NASA Astrophysics Data System (ADS)

Khosronejad, A.

2016-12-01

Recently, world has been witnessing significant enhancements in computing power of supercomputers. Computer clusters in conjunction with the advanced mathematical algorithms has set the stage for developing and applying powerful numerical tools to tackle some of the most intricate geophysical challenges that today`s engineers face. One such challenge is to understand how turbulent flows, in real-world settings, interact with (a) rigid and/or mobile complex bed bathymetry of waterways and sea-beds in the coastal areas; (b) objects with complex geometry that are fully or partially immersed; and (c) free-surface of waterways and water surface waves in the coastal area. This understanding is especially important because the turbulent flows in real-world environments are often bounded by geometrically complex boundaries, which dynamically deform and give rise to multi-scale and multi-physics transport phenomena, and characterized by multi-lateral interactions among various phases (e.g. air/water/sediment phases). Herein, I present some of the multi-scale and multi-physics geophysical fluid mechanics processes that I have attempted to study using an in-house high-performance computational model, the so-called VFS-Geophysics. More specifically, I will present the simulation results of turbulence/sediment/solute/turbine interactions in real-world settings. Parts of the simulations I present are performed to gain scientific insights into the processes such as sand wave formation (A. Khosronejad, and F. Sotiropoulos, (2014), Numerical simulation of sand waves in a turbulent open channel flow, Journal of Fluid Mechanics, 753:150-216), while others are carried out to predict the effects of climate change and large flood events on societal infrastructures ( A. Khosronejad, et al., (2016), Large eddy simulation of turbulence and solute transport in a forested headwater stream, Journal of Geophysical Research:, doi: 10.1002/2014JF003423).

NASA today, and a vision for tomorrow. [The NASA Administrator's Speech to the American Geophysical Union on 26 May 1994

NASA Technical Reports Server (NTRS)

Goldin, Daniel S.

1994-01-01

Under the administration of Dan Goldin's leadership, NASA is reinventing itself. In the process, the agency is also searching for a vision to define its role, both as a US Government agency and as a leading force in humanity's exploration of space. An adaption of Goldin's speech to the American Geophysical Union on 26 May 1994 in which he proposes one possible unifying vision is presented.

Evaluation of using digital gravity field models for zoning map creation

NASA Astrophysics Data System (ADS)

Loginov, Dmitry

2018-05-01

At the present time the digital cartographic models of geophysical fields are taking a special significance into geo-physical mapping. One of the important directions to their application is the creation of zoning maps, which allow taking into account the morphology of geophysical field in the implementation automated choice of contour intervals. The purpose of this work is the comparative evaluation of various digital models in the creation of integrated gravity field zoning map. For comparison were chosen the digital model of gravity field of Russia, created by the analog map with scale of 1 : 2 500 000, and the open global model of gravity field of the Earth - WGM2012. As a result of experimental works the four integrated gravity field zoning maps were obtained with using raw and processed data on each gravity field model. The study demonstrates the possibility of open data use to create integrated zoning maps with the condition to eliminate noise component of model by processing in specialized software systems. In this case, for solving problem of contour intervals automated choice the open digital models aren't inferior to regional models of gravity field, created for individual countries. This fact allows asserting about universality and independence of integrated zoning maps creation regardless of detail of a digital cartographic model of geo-physical fields.

Teaching Computational Geophysics Classes using Active Learning Techniques

NASA Astrophysics Data System (ADS)

Keers, H.; Rondenay, S.; Harlap, Y.; Nordmo, I.

2016-12-01

We give an overview of our experience in teaching two computational geophysics classes at the undergraduate level. In particular we describe The first class is for most students the first programming class and assumes that the students have had an introductory course in geophysics. In this class the students are introduced to basic Matlab skills: use of variables, basic array and matrix definition and manipulation, basic statistics, 1D integration, plotting of lines and surfaces, making of .m files and basic debugging techniques. All of these concepts are applied to elementary but important concepts in earthquake and exploration geophysics (including epicentre location, computation of travel time curves for simple layered media plotting of 1D and 2D velocity models etc.). It is important to integrate the geophysics with the programming concepts: we found that this enhances students' understanding. Moreover, as this is a 3 year Bachelor program, and this class is taught in the 2nd semester, there is little time for a class that focusses on only programming. In the second class, which is optional and can be taken in the 4th or 6th semester, but often is also taken by Master students we extend the Matlab programming to include signal processing and ordinary and partial differential equations, again with emphasis on geophysics (such as ray tracing and solving the acoustic wave equation). This class also contains a project in which the students have to write a brief paper on a topic in computational geophysics, preferably with programming examples. When teaching these classes it was found that active learning techniques, in which the students actively participate in the class, either individually, in pairs or in groups, are indispensable. We give a brief overview of the various activities that we have developed when teaching theses classes.

Broadband geophysical time series data from a stressed environment

NASA Astrophysics Data System (ADS)

Pun, W.; Saleh, R.; Zwaan, D.; Milkereit, B.; Valley, B.; Pilz, M.; Milkereit, C.; Milkereit, R.

2011-12-01

As classical exploration geophysical tools and techniques find new application in time lapse and monitoring studies, a fresh look at the performance and repeatability of various geophysical techniques is worth to take a closer look. We used an active, deep mine site close to Sudbury (Canada) for 3D deployment of broadband geophysical sensors for passive monitoring and detecting anomalous regions in the earth based on physical rock properties. In addition, we conducted controlled source experiments to evaluate repeatability of geophysical sources. To extend from detection to monitoring, continuous repeated measurements are necessary over a long period of time. If a controlled source is stable, the convolution problem is simplified such that any variation in the geophysical data is an effect of the earth's response. Repeated measurements are important for in-mine use to provide a better insight of stress and strain changes due to natural events and mining processes. The development, build-up and redistribution of stress lead to rock failures that can have disastrous consequences if they occur in an uncontrolled manner. In this project, different continuous and repeated in-situ geophysical measurements from a deep underground mine were analyzed to validate the feasibility of in-mine monitoring. Data acquisition tests covered both active and passive methods: gravity meter, fibre optic strain meters, fixed and portable three-component seismic arrays, EM induction coils and borehole based DC/IP resistivity sensors. The newly acquired data cover a wide range of frequencies which allow the study of short- and long-period events, ranging from 10-5 Hz to 10 kHz. Earth tides, global seismic events, tremors, acoustic emissions (microseismic events) and blasts were recorded within a 3D volume.

Archaeological Feedback as a Research Methodology in Near-Surface Geophysics

NASA Astrophysics Data System (ADS)

Maillol, J.; Ortega-Ramírez, J.; Berard, B.

2005-05-01

A unique characteristic of archaeological geophysics is to present the researchers in applied geophysics with the opportunity to verify their interpretation of geophysical data through the direct observation of often extremely detailed excavations. This is usually known as archaeological feedback. Archaeological materials have been slowly buried over periods ranging from several hundreds to several thousands of years, undergoing natural sedimentary and soil-forming processes. Once excavated, archaeological features therefore constitute more realistic test subjects than the targets artifically buried in common geophysical test sites. We are presenting the outcome of several such verification tests aimed at clarifying issues in geometry and spatial resolution of ground penetrating radar (GPR) images. On the site of a Roman villa in SE Portugal 500 Mhz GPR images are shown to depict very accurately the position and geometry of partially excavated remains. In the Maya city of Palenque, Mexico, 900 Mhz data allows the depth of tombs and natural cavities to be determined with cm accuracy. The predicted lateral extent of the cavities is more difficult to match with the reality due to the cluttering caused by high frequency. In the rainforest of Western Africa, 500 MHz GPR was used to prospect for stone tool sites. When very careful positioning and high density data sampling is achieved, stones can be accurately located and retrieved at depths exceeding 1 m with maximum positioning errors of 12cm horizontally and 2 cm vertically. In more difficult data collection conditions however, errors in positioning are shown to actually largely exceed the predictions based on quantitative theoretical resolution considerations. Geophysics has long been recognized as a powerful tool for prospecting and characterizing archaeological sites. Reciprocally, these results show that archaeology is an unparalleled test environment for the assesment and development of high resolution geophysical methods.

Integrated Approaches On Archaeo-Geophysical Data

NASA Astrophysics Data System (ADS)

Kucukdemirci, M.; Piro, S.; Zamuner, D.; Ozer, E.

2015-12-01

Key words: Ground Penetrating Radar (GPR), Magnetometry, Geophysical Data Integration, Principal Component Analyse (PCA), Aizanoi Archaeological Site An application of geophysical integration methods which often appealed are divided into two classes as qualitative and quantitative approaches. This work focused on the application of quantitative integration approaches, which involve the mathematical and statistical integration techniques, on the archaeo-geophysical data obtained in Aizanoi Archaeological Site,Turkey. Two geophysical methods were applied as Ground Penetrating Radar (GPR) and Magnetometry for archaeological prospection on the selected archaeological site. After basic data processing of each geophysical method, the mathematical approaches of Sums and Products and the statistical approach of Principal Component Analysis (PCA) have been applied for the integration. These integration approches were first tested on synthetic digital images before application to field data. Then the same approaches were applied to 2D magnetic maps and 2D GPR time slices which were obtained on the same unit grids in the archaeological site. Initially, the geophysical data were examined individually by referencing with archeological maps and informations obtained from archaeologists and some important structures as possible walls, roads and relics were determined. The results of all integration approaches provided very important and different details about the anomalies related to archaeological features. By using all those applications, integrated images can provide complementary informations as well about the archaeological relics under the ground. Acknowledgements The authors would like to thanks to Scientific and Technological Research Council of Turkey (TUBITAK), Fellowship for Visiting Scientists Programme for their support, Istanbul University Scientific Research Project Fund, (Project.No:12302) and archaeologist team of Aizanoi Archaeological site for their support during the field work.

Geophysical methods for road construction and maintenance

NASA Astrophysics Data System (ADS)

Rasul, Hedi; Karlson, Caroline; Jamali, Imran; Earon, Robert; Olofsson, Bo

2015-04-01

Infrastructure, such as road transportation, is a vital in civilized societies; which need to be constructed and maintained regularly. A large part of the project cost is attributed to subsurface conditions, where unsatisfactory conditions could increase either the geotechnical stabilization measures needed or the design cost itself. A way to collect information of the subsurface and existing installations which can lead to measures reducing the project cost and damage is to use geophysical methods during planning, construction and maintenance phases. The moisture in road layers is an important factor, which will affect the bearing capacity of the construction as well as the maintenances. Moisture in the road is a key factor for a well-functioning road. On the other hand the excessive moisture is the main reason of road failure and problems. From a hydrological point of view geophysical methods could help road planners identify the water table, geological strata, pollution arising from the road and the movement of the pollution before, during and after construction. Geophysical methods also allow road planners to collect valuable data for a large area without intrusive investigations such as with boreholes, i.e. minimizing the environmental stresses and costs. However, it is important to specify the investigation site and to choose the most appropriate geophysical method based on the site chosen and the objective of the investigation. Currently, numerous construction and rehabilitation projects are taking places around the world. Many of these projects are focused on infrastructural development, comprising both new projects and expansion of the existing infrastructural network. Geophysical methods can benefit these projects greatly during all phases. During the construction phase Ground Penetrating radar (GPR) is very useful in combination with Electrical Resistivity (ER) for detecting soil water content and base course compaction. However, ER and Electromagnetic (EM) methods can also be used for monitoring changes in water content and pollutant spreading during the maintenance phase. The objective of this study was to describe various geophysical methods which could benefit the road planning, construction and maintenance phases focusing on hydrological impacts.

Geological and technological assessment of artificial reef sites, Louisiana outer continental shelf

USGS Publications Warehouse

Pope, D.L.; Moslow, T.F.; Wagner, J.B.

1993-01-01

This paper describes the general procedures used to select sites for obsolete oil and gas platforms as artificial reefs on the Louisiana outer continental shelf (OCS). The methods employed incorporate six basic steps designed to resolve multiple-use conflicts that might otherwise arise with daily industry and commercial fishery operations, and to identify and assess both geological and technological constraints that could affect placement of the structures. These steps include: (1) exclusion mapping; (2) establishment of artificial reef planning areas; (3) database compilation; (4) assessment and interpretation of database; (5) mapping of geological and man-made features within each proposed reef site; and (6) site selection. Nautical charts, bathymetric maps, and offshore oil and gas maps were used for exclusion mapping, and to select nine regional planning areas. Pipeline maps were acquired from federal agencies and private industry to determine their general locations within each planning area, and to establish exclusion fairways along each pipeline route. Approximately 1600 line kilometers of high-resolution geophysical data collected by federal agencies and private industry was acquired for the nine planning areas. These data were interpreted to determine the nature and extent of near-surface geologic features that could affect placement of the structures. Seismic reflection patterns were also characterized to evaluate near-bottom sedimentation processes in the vicinity of each reef site. Geotechnical borings were used to determine the lithological and physical properties of the sediment, and for correlation with the geophysical data. Since 1987, five sites containing 10 obsolete production platforms have been selected on the Louisiana OCS using these procedures. Industry participants have realized a total savings of approximately US $1 500 000 in salvaging costs by converting these structures into artificial reefs. ?? 1993.

Destabilization of a Clay-Rich Slope by Rainfall : Monitoring of Precursons on an Hectometric Sliding Surface

NASA Astrophysics Data System (ADS)

Doan, M. L.; Bièvre, G.; Jongmans, D.; Helmstetter, A.; Radiguet, M.

2016-12-01

The Avignonet landslide is an active clay landslide near Grenoble, France, and therefore one of the monitored site of OMIV observatory. Previous geophysical investigation, including borehole drilling and surface geophysics proved that the landslide deformation is accommodated by several localized shear zones. The shallowest shear zone is about 5 m deep and extends over 100 m. Several sensors monitor the landslide. They record several precursors prior to a major disturbance of the landslide in autumn 2012, that affects all sensors in the landslide for several months. After major rainfalls, the two piezometers located near the 5 m deep interface got larger impulsional response to rainfall. The moderate rainfalls of Oct 26th caused the hydraulic head both reached a plateau before experiencing a sudden change, triggered by the small rainfall of Oct 31st. It's not the bigger rainfall that induced the disturbance. It was not the first rainfall neither.Other sensors suggest that the destabilization of the landslide was progressive. Spontaneous potential sensors regularly spaced within the 100 m wide sensors begin to separate after Oct 28th, suggesting a landslide wide precursor. Repeated microseismic events, of high frequency, suggesting a local origin, are more frequent. Their occurrence peaks after the small rainfall of Oct 29th and again on Oct 31st, before the rainfall that triggered the disturbance. They stop at the same time as sudden change in piezometric data. Despite the lack of displacement sensor, it is assumed that the 5 m deep shear zone slipped on Oct 31st, since it affects the piezometer sampling this interface. The data shows a progressive path towards destabilization. Especially, triggering of the landslide disturbances is associated to the cumulative effect of seismic activity and rainfall, even minor. This suggests a hydromechanical process.

Reports of Planetary Geology and Geophysics Program, 1984

NASA Technical Reports Server (NTRS)

Holt, H. E. (Compiler); Watters, T. R. (Compiler)

1985-01-01

Topics include outer planets and satellites; asteroids and comets; Venus; lunar origin and solar dynamics; cratering process; planetary interiors, petrology, and geochemistry; volcanic processes; aeolian processes and landforms; fluvial processes; geomorphology; periglacial and permafrost processes; remote sensing and regolith studies; structure, tectonics, and stratigraphy; geological mapping, cartography, and geodesy; and radar applications.

Towards 3D Noise Source Localization using Matched Field Processing

NASA Astrophysics Data System (ADS)

Umlauft, J.; Walter, F.; Lindner, F.; Flores Estrella, H.; Korn, M.

2017-12-01

The Matched Field Processing (MFP) is an array-processing and beamforming method, initially developed in ocean acoustics, that locates noise sources in range, depth and azimuth. In this study, we discuss the applicability of MFP for geophysical problems on the exploration scale and its suitability as a monitoring tool for near surface processes. First, we used synthetic seismograms to analyze the resolution and sensitivity of MFP in a 3D environment. The inversion shows how the localization accuracy is affected by the array design, pre-processing techniques, the velocity model and considered wave field characteristics. Hence, we can formulate guidelines for an improved MFP handling. Additionally, we present field datasets, aquired from two different environmental settings and in the presence of different source types. Small-scale, dense aperture arrays (Ø <1 km) were installed on a natural CO2 degassing field (Czech Republic) and on a Glacier site (Switzerland). The located noise sources form distinct 3 dimensional zones and channel-like structures (several 100 m depth range), which could be linked to the expected environmental processes taking place at each test site. Furthermore, fast spatio-temporal variations (hours to days) of the source distribution could be succesfully monitored.

Application of field geophysics in geomorphology: Advances and limitations exemplified by case studies

NASA Astrophysics Data System (ADS)

Schrott, Lothar; Sass, Oliver

2008-01-01

During the last decade, the use of geophysical techniques has become popular in many geomorphological studies. However, the correct handling of geophysical instruments and the subsequent processing of the data they yield are difficult tasks. Furthermore, the description and interpretation of geomorphological settings to which they apply can significantly influence the data gathering and subsequent modelling procedure ( e.g. achieving a maximum depth of 30 m requires a certain profile length and geophone spacing or a particular frequency of antenna). For more than three decades geophysical techniques have been successfully applied, for example, in permafrost studies. However, in many cases complex or more heterogeneous subsurface structures could not be adequately interpreted due to limited computer facilities and time consuming calculations. As a result of recent technical improvements, geophysical techniques have been applied to a wider spectrum of geomorphological and geological settings. This paper aims to present some examples of geomorphological studies that demonstrate the powerful integration of geophysical techniques and highlight some of the limitations of these techniques. A focus has been given to the three most frequently used techniques in geomorphology to date, namely ground-penetrating radar, seismic refraction and DC resistivity. Promising applications are reported for a broad range of landforms and environments, such as talus slopes, block fields, landslides, complex valley fill deposits, karst and loess covered landforms. A qualitative assessment highlights suitable landforms and environments. The techniques can help to answer yet unsolved questions in geomorphological research regarding for example sediment thickness and internal structures. However, based on case studies it can be shown that the use of a single geophysical technique or a single interpretation tool is not recommended for many geomorphological surface and subsurface conditions as this may lead to significant errors in interpretation. Because of changing physical properties of the subsurface material ( e.g. sediment, water content) in many cases only a combination of two or sometimes even three geophysical methods gives sufficient insight to avoid serious misinterpretation. A "good practice guide" has been framed that provides recommendations to enable the successful application of three important geophysical methods in geomorphology and to help users avoid making serious mistakes.

The Prediction-Focused Approach: An opportunity for hydrogeophysical data integration and interpretation

NASA Astrophysics Data System (ADS)

Hermans, Thomas; Nguyen, Frédéric; Klepikova, Maria; Dassargues, Alain; Caers, Jef

2017-04-01

Hydrogeophysics is an interdisciplinary field of sciences aiming at a better understanding of subsurface hydrological processes. If geophysical surveys have been successfully used to qualitatively characterize the subsurface, two important challenges remain for a better quantification of hydrological processes: (1) the inversion of geophysical data and (2) their integration in hydrological subsurface models. The classical inversion approach using regularization suffers from spatially and temporally varying resolution and yields geologically unrealistic solutions without uncertainty quantification, making their utilization for hydrogeological calibration less consistent. More advanced techniques such as coupled inversion allow for a direct use of geophysical data for conditioning groundwater and solute transport model calibration. However, the technique is difficult to apply in complex cases and remains computationally demanding to estimate uncertainty. In a recent study, we investigate a prediction-focused approach (PFA) to directly estimate subsurface physical properties from geophysical data, circumventing the need for classic inversions. In PFA, we seek a direct relationship between the data and the subsurface variables we want to predict (the forecast). This relationship is obtained through a prior set of subsurface models for which both data and forecast are computed. A direct relationship can often be derived through dimension reduction techniques. PFA offers a framework for both hydrogeophysical "inversion" and hydrogeophysical data integration. For hydrogeophysical "inversion", the considered forecast variable is the subsurface variable, such as the salinity. An ensemble of possible solutions is generated, allowing uncertainty quantification. For hydrogeophysical data integration, the forecast variable becomes the prediction we want to make with our subsurface models, such as the concentration of contaminant in a drinking water production well. Geophysical and hydrological data are combined to derive a direct relationship between data and forecast. We illustrate the process for the design of an aquifer thermal energy storage (ATES) system. An ATES system can theoretically recover in winter the heat stored in the aquifer during summer. In practice, the energy efficiency is often lower than expected due to spatial heterogeneity of hydraulic properties combined to a non-favorable hydrogeological gradient. A proper design of ATES systems should consider the uncertainty of the prediction related to those parameters. With a global sensitivity analysis, we identify sensitive parameters for heat storage prediction and validate the use of a short term heat tracing experiment monitored with geophysics to generate informative data. First, we illustrate how PFA can be used to successfully derive the distribution of temperature in the aquifer from ERT during the heat tracing experiment. Then, we successfully integrate the geophysical data to predict medium-term heat storage in the aquifer using PFA. The result is a full quantification of the posterior distribution of the prediction conditioned to observed data in a relatively limited time budget.

Geophysical methods for monitoring soil stabilization processes

NASA Astrophysics Data System (ADS)

Saneiyan, Sina; Ntarlagiannis, Dimitrios; Werkema, D. Dale; Ustra, Andréa

2018-01-01

Soil stabilization involves methods used to turn unconsolidated and unstable soil into a stiffer, consolidated medium that could support engineered structures, alter permeability, change subsurface flow, or immobilize contamination through mineral precipitation. Among the variety of available methods carbonate precipitation is a very promising one, especially when it is being induced through common soil borne microbes (MICP - microbial induced carbonate precipitation). Such microbial mediated precipitation has the added benefit of not harming the environment as other methods can be environmentally detrimental. Carbonate precipitation, typically in the form of calcite, is a naturally occurring process that can be manipulated to deliver the expected soil strengthening results or permeability changes. This study investigates the ability of spectral induced polarization and shear-wave velocity for monitoring calcite driven soil strengthening processes. The results support the use of these geophysical methods as soil strengthening characterization and long term monitoring tools, which is a requirement for viable soil stabilization projects. Both tested methods are sensitive to calcite precipitation, with SIP offering additional information related to long term stability of precipitated carbonate. Carbonate precipitation has been confirmed with direct methods, such as direct sampling and scanning electron microscopy (SEM). This study advances our understanding of soil strengthening processes and permeability alterations, and is a crucial step for the use of geophysical methods as monitoring tools in microbial induced soil alterations through carbonate precipitation.

The time-domain behavior of power-law noises. [of many geophysical phenomena

NASA Technical Reports Server (NTRS)

Agnew, Duncan C.

1992-01-01

The power spectra of many geophysical phenomena are well approximated by a power-law dependence on frequency or wavenumber. A simple expression for the root-mean-square variability of a process with such a spectrum over an interval of time or space is derived. The resulting expression yields the powerlaw time dependence characteristic of fractal processes, but can be generalized to give the temporal variability for more general spectral behaviors. The method is applied to spectra of crustal strain (to show what size of strain events can be detected over periods of months to seconds) and of sea level (to show the difficulty of extracting long-term rates from short records).

Dark-soliton collisions for a coupled AB system in the geophysical fluids or nonlinear optics

NASA Astrophysics Data System (ADS)

Xie, Xi-Yang; Meng, Gao-Qing

2018-02-01

Under investigation in this paper is a coupled AB system, which describes the marginally unstable baroclinic wave packets in the geophysical fluids or ultra-short pulses in nonlinear optics. As the dark solitons are more resistant against various perturbations than the bright ones, we aim to investigate the dark solitons in the geophysical fluids or nonlinear optics. Dark one- and two-soliton solutions for such a system are derived based on the bilinear forms and propagations of the one solitons and collisions between the two solitons are graphically illustrated and analyzed. Further, influences of the coefficients λ and σ on the solitons are discussed, where λ is a parameter measuring the state of the basic flow and σ is the group velocity. The dark-one solitons with invariant shapes and amplitudes are viewed, and elastic collisions between the dark-two solitons are observed. Also, elastic collision between the bright and dark solitons is viewed, and the dark soliton is found to possess two peaks. σ is found to affect the widths of the dark-one solitons and the travelling directions of the dark-two solitons. It is shown that λ cannot influence shapes of A1 and A2, but affect the plane of the one soliton for B, and the two-peak dark soliton for B changes to the single-peak one with the value of λ decreasing, where A1 and A2 are the packets of short waves and B is the mean flow.

Unleashing Geophysics Data with Modern Formats and Services

NASA Astrophysics Data System (ADS)

Ip, Alex; Brodie, Ross C.; Druken, Kelsey; Bastrakova, Irina; Evans, Ben; Kemp, Carina; Richardson, Murray; Trenham, Claire; Wang, Jingbo; Wyborn, Lesley

2016-04-01

Geoscience Australia (GA) is the national steward of large volumes of geophysical data extending over the entire Australasian region and spanning many decades. The volume and variety of data which must be managed, coupled with the increasing need to support machine-to-machine data access, mean that the old "click-and-ship" model delivering data as downloadable files for local analysis is rapidly becoming unviable - a "big data" problem not unique to geophysics. The Australian Government, through the Research Data Services (RDS) Project, recently funded the Australian National Computational Infrastructure (NCI) to organize a wide range of Earth Systems data from diverse collections including geoscience, geophysics, environment, climate, weather, and water resources onto a single High Performance Data (HPD) Node. This platform, which now contains over 10 petabytes of data, is called the National Environmental Research Data Interoperability Platform (NERDIP), and is designed to facilitate broad user access, maximise reuse, and enable integration. GA has contributed several hundred terabytes of geophysical data to the NERDIP. Historically, geophysical datasets have been stored in a range of formats, with metadata of varying quality and accessibility, and without standardised vocabularies. This has made it extremely difficult to aggregate original data from multiple surveys (particularly un-gridded geophysics point/line data) into standard formats suited to High Performance Computing (HPC) environments. To address this, it was decided to use the NERDIP-preferred Hierarchical Data Format (HDF) 5, which is a proven, standard, open, self-describing and high-performance format supported by extensive software tools, libraries and data services. The Network Common Data Form (NetCDF) 4 API facilitates the use of data in HDF5, whilst the NetCDF Climate & Forecasting conventions (NetCDF-CF) further constrain NetCDF4/HDF5 data so as to provide greater inherent interoperability. The first geophysical data collection selected for transformation by GA was Airborne ElectroMagnetics (AEM) data which was held in proprietary-format files, with associated ISO 19115 metadata held in a separate relational database. Existing NetCDF-CF metadata profiles were enhanced to cover AEM and other geophysical data types, and work is underway to formalise the new geophysics vocabulary as a proposed extension to the Climate & Forecasting conventions. The richness and flexibility of HDF5's internal indexing mechanisms has allowed lossless restructuring of the AEM data for efficient storage, subsetting and access via either the NetCDF4/HDF5 APIs or Open-source Project for a Network Data Access Protocol (OPeNDAP) data services. This approach not only supports large-scale HPC processing, but also interactive access to a wide range of geophysical data in user-friendly environments such as iPython notebooks and more sophisticated cloud-enabled portals such as the Virtual Geophysics Laboratory (VGL). As multidimensional AEM datasets are relatively complex compared to other geophysical data types, the general approach employed in this project for modernizing AEM data is likely to be applicable to other geophysics data types. When combined with the use of standards-based data services and APIs, a coordinated, systematic modernisation will result in vastly improved accessibility to, and usability of, geophysical data in a wide range of computational environments both within and beyond the geophysics community.

Geological criteria and geophysical methods of natural bitumen deposits preparation to the development

NASA Astrophysics Data System (ADS)

Uspensky, B. V.; Borovsky, M. Ya; Vafin, R. F.; Valeeva, S. E.; Mudarisova, R. A.

2018-05-01

The article considers the provisions of the ontogenesis of the following factors in the formation of natural bitumen clusters in the Permian deposits of the Melekesskiy region: genetic, geodynamic, structural and hydrogeological. It is shown that tectonically weakened zones and zones of Neogene incisions development are fixed by high-precision gravimetry in the form of intense local minima of gravity. A favorable factor contributing to the "strengthening" of anomalous geophysical effects is the coincidence of the locations of these geological section heterogeneities in the plan. It is recommended at the stage of experimental-industrial operation a complex of geophysical methods for monitoring the processes of natural bitumen deposits development by means of secondary impact on the formation. High-precision magnetic, thermal and electrical prospecting in various modifications are used.

Data Management Considerations for the International Polar Year

NASA Astrophysics Data System (ADS)

Parsons, M. A.; Weaver, R. L.; Duerr, R.; Barry, R. G.

2004-12-01

The legacy of the International Geophysical Year and past International Polar Years is in the scientific data collected. The upcoming IPY will result in an unprecedented collection of geophysical and social science data from the polar regions. To realize the full scientific and interdisciplinary utility of these data it is essential to consider the design of data management systems early in the expirimental planning process. This paper will present an array of high level data management considerations for the IPY including cross-disciplinary data access, essential documentation, system guidance, and long-term data archiving. Specific recommendations from relevant international organizations such as the Joint Committee on Antarctic Data Management and the WCRP Climate and Cryosphere Programme will be considered. The potential role of the Electronic Geophysical Year and other International Years will also be discussed.

Alternative experiments using the geophysical fluid flow cell

NASA Technical Reports Server (NTRS)

Hart, J. E.

1984-01-01

This study addresses the possibility of doing large scale dynamics experiments using the Geophysical Fluid Flow Cell. In particular, cases where the forcing generates a statically stable stratification almost everywhere in the spherical shell are evaluated. This situation is typical of the Earth's atmosphere and oceans. By calculating the strongest meridional circulation expected in the spacelab experiments, and testing its stability using quasi-geostrophic stability theory, it is shown that strongly nonlinear baroclinic waves on a zonally symmetric modified thermal wind will not occur. The Geophysical Fluid Flow Cell does not have a deep enough fluid layer to permit useful studies of large scale planetary wave processes arising from instability. It is argued, however, that by introducing suitable meridional barriers, a significant contribution to the understanding of the oceanic thermocline problem could be made.

A spectacular coronal mass ejection event and associated phenomena

NASA Astrophysics Data System (ADS)

Ma, Yuan; Li, Chun-Sheng; Song, Qian

Based on the data taken from S. G. D. and relevant simultaneous observations of solar radio bursts, gamma-ray emission and geophysical effects on June 15, 1991 the relationships among these phenomena are discussed in this paper. Through the analyses it is considered that proton events and GLE events occurred on June 15 in 1991, which were the geophysic responses caused by CME (V>=750 km/s). Simultaneous observation of the bursts at the centimetric and decimetric wavelengths can obtain the U-shape spectrum of speak fluxes, which is still one of the effective tools for predicting proton events and its production mechanism can be explained by using the acceleration of the direct current field parallel to the magnetic field in the electric current sheet formed in the process of the production of spray prominences. However, the process in which electrons are accelerated up to the high energy state remains to be explained. The whole event of June 15 1991, from the coronal matter ejection (or the spray prominences in active regions) to the production of various geophysic effects, has explained and verified.

On the mutual relationship between conceptual models and datasets in geophysical monitoring of volcanic systems

NASA Astrophysics Data System (ADS)

Neuberg, J. W.; Thomas, M.; Pascal, K.; Karl, S.

2012-04-01

Geophysical datasets are essential to guide particularly short-term forecasting of volcanic activity. Key parameters are derived from these datasets and interpreted in different ways, however, the biggest impact on the interpretation is not determined by the range of parameters but controlled through the parameterisation and the underlying conceptual model of the volcanic process. On the other hand, the increasing number of sophisticated geophysical models need to be constrained by monitoring data, to transform a merely numerical exercise into a useful forecasting tool. We utilise datasets from the "big three", seismology, deformation and gas emissions, to gain insight in the mutual relationship between conceptual models and constraining data. We show that, e.g. the same seismic dataset can be interpreted with respect to a wide variety of different models with very different implications to forecasting. In turn, different data processing procedures lead to different outcomes even though they are based on the same conceptual model. Unsurprisingly, the most reliable interpretation will be achieved by employing multi-disciplinary models with overlapping constraints.

1980 Summer Study Program in Geophysical Fluid Dynamics - Coherent Features in Geophysical Flows.

DTIC Science & Technology

1980-11-01

odei un a inplii.ude motions on the beta plane. He extended the analysis to more complex flows in the ocean and the atmosphere and in the process...Technology Maxworthy, Anthony University of Southern California McWilliams, James National Center for Atmospheric Reserch Nelkin, Mark Cornell University...Nortweg-de Vries equation via a model of finite amplitude motions on the beta plane. He extended the analysis to more complex flows in the ocean and the

Atmospheric and Oceanic Processes in the Vicinity of an Island Strait

DTIC Science & Technology

2011-03-01

the uniquely wind-driven origin of the Philippine dipole eddies. By contrast, in other volcanic island regions of the world (including the Hawaiian...Aristegui, and F. Herrera. 2000. Lee region of Gran Canaria . Journal of Geophysical Research 105(C7):17,173–17,193. Chang, C.-P., Z. Wang, and H...Gran Canaria ). Geophysical Research Letters 36, L14605, doi:10.1029/2008GL037010. Pullen, J., J.D. Doyle, P. May, C. Chavanne, P. Flament, and R.A

A survey of the theory of the Earth's rotation

NASA Technical Reports Server (NTRS)

Cannon, W. H.

1981-01-01

The theory of the Earth's rotation and the geophysical phenomena affecting it is examined. First principles are reviewed and the problem of polar motion and UT1 variations is formulated in considerable generality and detail. The effects of Earth deformations and the solid Earth tides are analyzed.

Detecting Buried Archaeological Remains by the Use of Geophysical Data Processing with 'Diffusion Maps' Methodology

NASA Astrophysics Data System (ADS)

Eppelbaum, Lev

2015-04-01

Geophysical methods are prompt, non-invasive and low-cost tool for quantitative delineation of buried archaeological targets. However, taking into account the complexity of geological-archaeological media, some unfavourable environments and known ambiguity of geophysical data analysis, a single geophysical method examination might be insufficient (Khesin and Eppelbaum, 1997). Besides this, it is well-known that the majority of inverse-problem solutions in geophysics are ill-posed (e.g., Zhdanov, 2002), which means, according to Hadamard (1902), that the solution does not exist, or is not unique, or is not a continuous function of observed geophysical data (when small perturbations in the observations will cause arbitrary mistakes in the solution). This fact has a wide application for informational, probabilistic and wavelet methodologies in archaeological geophysics (Eppelbaum, 2014a). The goal of the modern geophysical data examination is to detect the geophysical signatures of buried targets at noisy areas via the analysis of some physical parameters with a minimal number of false alarms and miss-detections (Eppelbaum et al., 2011; Eppelbaum, 2014b). The proposed wavelet approach to recognition of archaeological targets (AT) by the examination of geophysical method integration consists of advanced processing of each geophysical method and nonconventional integration of different geophysical methods between themselves. The recently developed technique of diffusion clustering combined with the abovementioned wavelet methods was utilized to integrate the geophysical data and detect existing irregularities. The approach is based on the wavelet packet techniques applied as to the geophysical images (or graphs) versus coordinates. For such an analysis may be utilized practically all geophysical methods (magnetic, gravity, seismic, GPR, ERT, self-potential, etc.). On the first stage of the proposed investigation a few tens of typical physical-archaeological models (PAM) (e.g., Eppelbaum et al., 2010; Eppelbaum, 2011) of the targets under study for the concrete area (region) are developed. These PAM are composed on the basis of the known archaeological and geological data, results of previous archaeogeophysical investigations and 3D modeling of geophysical data. It should be underlined that the PAMs must differ (by depth, size, shape and physical properties of AT as well as peculiarities of the host archaeological-geological media). The PAMs must include also noise components of different orders (corresponding to the archaeogeophysical conditions of the area under study). The same models are computed and without the AT. Introducing complex PAMs (for example, situated in the vicinity of electric power lines, some objects of infrastructure, etc. (Eppelbaum et al., 2001)) will reflect some real class of AT occurring in such unfavorable for geophysical searching conditions. Anomalous effects from such complex PAMs will significantly disturb the geophysical anomalies from AT and impede the wavelet methodology employment. At the same time, the 'self-learning' procedure laid in this methodology will help further to recognize the AT even in the cases of unfavorable S/N ratio. Modern developments in the wavelet theory and data mining are utilized for the analysis of the integrated data. Wavelet approach is applied for derivation of enhanced (e.g., coherence portraits) and combined images of geophysical fields. The modern methodologies based on the matching pursuit with wavelet packet dictionaries enables to extract desired signals even from strongly noised data (Averbuch et al., 2014). Researchers usually met the problem of extraction of essential features from available data contaminated by a random noise and by a non-relevant background (Averbuch et al., 2014). If the essential structure of a signal consists of several sine waves then we may represent it via trigonometric basis (Fourier analysis). In this case one can compare the signal with a set of sinusoids and extract consistent ones. An indicator of presence a wave in a signal f(t) is the Fourier coefficient ∫ f(t) sinwt dt. Wavelet analysis provides a rich library of waveforms available and fast, computationally efficient procedures of representation of signals and of selection of relevant waveforms. The basic assumption justifying an application of wavelet analysis is that the essential structure of a signal analyzed consists of not a large number of various waveforms. The best way to reveal this structure is representation of the signal by a set of basic elements containing waveforms coherent to the signal. For structures of the signal coherent to the basis, large coefficients are attributed to a few basic waveforms, whereas we expect small coefficients for the noise and structures incoherent to all basic waveforms. Wavelets are a family of functions ranging from functions of arbitrary smoothness to fractal ones. Wavelet procedure involves two aspects. The first one is a decomposition, i.e. breaking up a signal to obtain the wavelet coefficients and the 2nd one is a reconstruction, which consists of a reassembling the signal from coefficients There are many modifications of the WA. Note, first of all, so-called Continuous WA in whichsignal f(t) is tested for presence of waveforms ψ(t-b) a. Here, a is scaling parameter (dilation), bdetermines location of the wavelet ψ(t-b) a in a signal f(t). The integral ( ) ∫ t-b (W ψf) (b,a) = f (t) ψ a dt is the Continuous Wavelet Transform.When parameters a,b in ψ( ) t-ab take some discrete values, we have the Discrete Wavelet Transform. A general scheme of the Wavelet Decomposition Tree is shown, for instance, in (Averbuch et al., 2014; Eppelbaum et al., 2014). The signal is compared with the testing signal on each scale. It is estimated wavelet coefficients which enable to reconstruct the 1st approximation of the signal and details. On the next level, wavelet transform is applied to the approximation. Then, we can present A1 as A2 + D2, etc. So, if S - Signal, A - Approximation, D - Details, then S = A1 + D1 = A2 + D2 + D1 = A3 + D3 + D2 + D1. Wavelet packet transform is applied to both low pass results (approximations) and high pass results (Details). For analyzing the geophysical data, we used a technique based on the algorithm to characterize a geophysical image by a limited number of parameters (Eppelbaum et al., 2012). This set of parameters serves as a signature of the image and is utilized for discrimination of images (a) containing AT from the images (b) non-containing AT (let will designate these images as N). The constructed algorithm consists of the following main phases: (a) collection of the database, (b) characterization of geophysical images, (c) and dimensionality reduction. Then, each image is characterized by the histogram of the coherency directions (Alperovich et al., 2013). As a result of the previous steps we obtain two sets: containing AT and N of the signatures vectors for geophysical images. The obtained 3D set of the data representatives can be used as a reference set for the classification of newly arriving geophysical data. The obtained data sets are reduced by embedding features vectors into the 3D Euclidean space using the so-called diffusion map. This map enables to reveal the internal structure of the datasets AT and N and to distinctly separate them. For this, a matrix of the diffusion distances for the combined feature matrix F = FN ∴ FC of size 60 x C is constructed (Coifman and Lafon, 2006; Averbuch et al., 2010). Then, each row of the matrices FN and FC is projected onto three first eigenvectors of the matrix D(F ). As a result, each data curve is represented by a 3D point in the Euclidean space formed by eigenvectors of D(F ). The Euclidean distances between these 3D points reflect the similarity of the data curves. The scattered projections of the data curves onto the diffusion eigenvectors will be composed. Finally we observe that as a result of the above operations we embedded the original data into 3-dimensional space where data related to the AT subsurface are well separated from the N data. This 3D set of the data representatives can be used as a reference set for the classification of newly arriving data. Geophysically it means a reliable division of the studied areas for the AT-containing and not containing (N) these objects. Testing this methodology for delineation of archaeological cavities by magnetic and gravity data analysis displayed an effectiveness of this approach. References Alperovich, L., Eppelbaum, L., Zheludev, V., Dumoulin, J., Soldovieri, F., Proto, M., Bavusi, M. and Loperte, A., 2013. A new combined wavelet methodology applied to GPR and ERT data in the Montagnole experiment (French Alps). Journal of Geophysics and Engineering, 10, No. 2, 025017, 1-17. Averbuch, A., Hochman, K., Rabin, N., Schclar, A. and Zheludev, V., 2010. A diffusion frame-work for detection of moving vehicles. Digital Signal Processing, 20, No.1, 111-122. Averbuch A.Z., Neittaanmäki, P., and Zheludev, V.A., 2014. Spline and Spline Wavelet Methods with Applications to Signal and Image Processing. Volume I: Periodic Splines. Springer. Coifman, R.R. and Lafon, S., 2006. Diffusion maps, Applied and Computational Harmonic Analysis. Special issue on Diffusion Maps and Wavelets, 21, No. 7, 5-30. Eppelbaum, L.V., 2011. Study of magnetic anomalies over archaeological targets in urban conditions. Physics and Chemistry of the Earth, 36, No. 16, 1318-1330. Eppelbaum, L.V., 2014a. Geophysical observations at archaeological sites: Estimating informational content. Archaeological Prospection, 21, No. 2, 25-38. Eppelbaum, L.V. 2014b. Four Color Theorem and Applied Geophysics. Applied Mathematics, 5, 358-366. Eppelbaum, L.V., Alperovich, L., Zheludev, V. and Pechersky, A., 2011. Application of informational and wavelet approaches for integrated processing of geophysical data in complex environments. Proceed. of the 2011 SAGEEP Conference, Charleston, South Carolina, USA, 24, 24-60. Eppelbaum, L.V., Khesin, B.E. and Itkis, S.E., 2001. Prompt magnetic investigations of archaeological remains in areas of infrastructure development: Israeli experience. Archaeological Prospection, 8, No.3, 163-185. Eppelbaum, L.V., Khesin, B.E. and Itkis, S.E., 2010. Archaeological geophysics in arid environments: Examples from Israel. Journal of Arid Environments, 74, No. 7, 849-860. Eppelbaum, L.V., Zheludev, V. and Averbuch, A., 2014. Diffusion maps as a powerful tool for integrated geophysical field analysis to detecting hidden karst terranes. Izv. Acad. Sci. Azerb. Rep., Ser.: Earth Sciences, No. 1-2, 36-46. Hadamard, J., 1902. Sur les problèmes aux dérivées partielles et leur signification physique. Princeton University Bulletin, 13, 49-52. Khesin, B.E. and Eppelbaum, L.V., 1997. The number of geophysical methods required for target classification: quantitative estimation. Geoinformatics, 8, No.1, 31-39. Zhdanov, M.S., 2002. Geophysical Inverse Theory and Regularization Problems. Methods in Geochemistry and Geophysics, Vol. 36. Elsevier, Amsterdam.

Petrophysics Features of the Hydrocarbon Reservoirs in the Precambrian Crystalline Basement

NASA Astrophysics Data System (ADS)

Plotnikova, Irina

2014-05-01

A prerequisite for determining the distribution patterns of reservoir zones on the section of crystalline basement (CB) is the solution of a number of problems connected with the study of the nature and structure of empty spaces of reservoirs with crystalline basement (CB) and the impact of petrological, and tectonic factors and the intensity of the secondary transformation of rocks. We decided to choose the Novoelhovskaya well # 20009 as an object of our research because of the following factors. Firstly, the depth of the drilling of the Precambrian crystalline rocks was 4077 m ( advance heading - 5881 m) and it is a maximum for the Volga-Urals region. Secondly, petrographic cut of the well is made on core and waste water, and the latter was sampled regularly and studied macroscopically. Thirdly, a wide range of geophysical studies were performed for this well, which allowed to identify promising areas of collector with high probability. Fourth, along with geological and technical studies that were carried out continuously (including washing and bore hole redressing periods), the studies of the gaseous component of deep samples of clay wash were also carried out, which indirectly helped us estimate reservoir properties and fluid saturation permeable zones. As a result of comprehensive analysis of the stone material and the results of the geophysical studies we could confidently distinguish 5 with strata different composition and structure in the cut of the well. The dominating role in each of them is performed by rocks belonging to one of the structural-material complexes of Archean, and local variations in composition and properties are caused by later processes of granitization on different stages and high temperature diaphthoresis imposed on them. Total capacity of reservoir zones identified according to geophysical studies reached 1034.2 m, which corresponds to 25.8% of the total capacity of 5 rock masses. However, the distribution of reservoirs within the cut is uneven. The manifestation of reservoir properties of crystalline rocks and their gas content is to a high degree connected with those parts of the cut of the well that are represented by Bolshecheremshanskaya series of rocks. The analysis of the distribution of reservoir intervals that were identified in the well section # 20009 according to the geophysical studies showed that they tend to coincide with the intervals of intensive secondary changes and rock breaking, or with contacts of series of rocks or thick layers of rocks that differ greatly in physical and mechanical properties. About half of the potential reservoir zones are characterized by explicit, well-defined fractures, which was determined according to core and wastewater samples, as well as with the help of caliper gauge. The rocks of a Bolshecheremshanskaya series were more exposed to the repeated impact of the parallel processes (mylonitization, diaphtoresis, migmatization, etc.), or they were simply more affected by these processes, and that led to the characteristic distribution of collector areas, temperature and gas anomalies along the borehole cut. The presence of Bolshecheremshanskaya quartz series in the material composition of the rocks caused, firstly, increased amount of fractures, and secondly, the preservation of the porous-cavernous space frame within the superimposed secondary processes.

Improved estimation of hydraulic conductivity by combining stochastically simulated hydrofacies with geophysical data.

PubMed

Zhu, Lin; Gong, Huili; Chen, Yun; Li, Xiaojuan; Chang, Xiang; Cui, Yijiao

2016-03-01

Hydraulic conductivity is a major parameter affecting the output accuracy of groundwater flow and transport models. The most commonly used semi-empirical formula for estimating conductivity is Kozeny-Carman equation. However, this method alone does not work well with heterogeneous strata. Two important parameters, grain size and porosity, often show spatial variations at different scales. This study proposes a method for estimating conductivity distributions by combining a stochastic hydrofacies model with geophysical methods. The Markov chain model with transition probability matrix was adopted to re-construct structures of hydrofacies for deriving spatial deposit information. The geophysical and hydro-chemical data were used to estimate the porosity distribution through the Archie's law. Results show that the stochastic simulated hydrofacies model reflects the sedimentary features with an average model accuracy of 78% in comparison with borehole log data in the Chaobai alluvial fan. The estimated conductivity is reasonable and of the same order of magnitude of the outcomes of the pumping tests. The conductivity distribution is consistent with the sedimentary distributions. This study provides more reliable spatial distributions of the hydraulic parameters for further numerical modeling.

Hands-on Marine Geology and Geophysics Field Instruction at the University of Texas

NASA Astrophysics Data System (ADS)

Saustrup, S.; Gulick, S. P. S.; Goff, J. A.; Fernandez, R.; Davis, M. B.; Duncan, D.

2015-12-01

The University of Texas Institute for Geophysics, part of the Jackson School of Geosciences, annually offers an intensive three-week marine geology and geophysics field course during the spring-summer intersession. Now in its ninth year, the course provides instruction in survey design, data acquisition, processing, interpretation, and visualization. Methods covered include seismic reflection, multibeam bathymetry, sidescan sonar, and sediment sampling. The emphasis of the course is team-oriented, hands-on, field training in real-world situations. The course begins with classroom instruction covering the field area and field methods, followed by a week of at-sea field work in 4-student teams. The students then return to the classroom where they integrate, interpret, and visualize data using industry-standard software. The teams present results in a series of professional-level final presentations before academic and industry supporters. Our rotating field areas provide ideal locations for students to investigate coastal and sedimentary processes of the Gulf Coast and continental shelf . In the field, student teams rotate between two research vessels: the smaller vessel, the Jackson School's newly-commissioned R/V Scott Petty (26 feet LOA), is used principally for multibeam bathymetry, sidescan sonar, and sediment sampling; the other, NOAA's R/V Manta (82 feet LOA) is used for high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, gravity coring, and vibracoring. Teams also rotate through a field laboratory performing processing of geophysical data and sediment samples. This past year's course in Freeport, Texas proceeded unabated despite concurrent record-breaking rainfall and flooding, which offered students a unique opportunity to observe and image, in real time, flood-related bedform migration on a time scale of hours. The data also allowed an in-class opportunity to examine natural and anthropogenic processes recorded in the river and coastal morphology and stratigraphy. http://www.ig.utexas.edu/research/mgg/courses/geof348K/

On the optimization of electromagnetic geophysical data: Application of the PSO algorithm

NASA Astrophysics Data System (ADS)

Godio, A.; Santilano, A.

2018-01-01

Particle Swarm optimization (PSO) algorithm resolves constrained multi-parameter problems and is suitable for simultaneous optimization of linear and nonlinear problems, with the assumption that forward modeling is based on good understanding of ill-posed problem for geophysical inversion. We apply PSO for solving the geophysical inverse problem to infer an Earth model, i.e. the electrical resistivity at depth, consistent with the observed geophysical data. The method doesn't require an initial model and can be easily constrained, according to external information for each single sounding. The optimization process to estimate the model parameters from the electromagnetic soundings focuses on the discussion of the objective function to be minimized. We discuss the possibility to introduce in the objective function vertical and lateral constraints, with an Occam-like regularization. A sensitivity analysis allowed us to check the performance of the algorithm. The reliability of the approach is tested on synthetic, real Audio-Magnetotelluric (AMT) and Long Period MT data. The method appears able to solve complex problems and allows us to estimate the a posteriori distribution of the model parameters.

Geophysical data from offshore of the Gulf Islands National Seashore, Cat Island to Western Horn Island, Mississippi

USGS Publications Warehouse

Pendleton, E.A.; Baldwin, W.E.; Danforth, W.W.; DeWitt, N.T.; Forde, A.S.; Foster, D.S.; Kelso, K.W.; Pfeiffer, W.R.; Turecek, A.M.; Flocks, J.G.; Twichell, D.C.

2011-01-01

This report contains the geophysical and geospatial data that were collected along the western offshore side of the Gulf Islands of Mississippi on the research vessel Tommy Munro during two cruises in 2010. Geophysical data were collected by the U.S. Geological Survey in Woods Hole, Massachusetts, and St. Petersburg, Forida, in cooperation with the U.S. Army Corps of Engineers Mobile District. Bathymetric-sonar, sidescan-sonar, and Chirp seismic-reflection data were acquired with the following equipment, respectively: Systems Engineering and Assessment, Ltd., SwathPlus interferometric sonars; Klein 3000 and 3900 dual-frequency sidescan sonars; and an EdgeTech 512i Chirp sub-bottom profiling system. The long-term goals of this mapping effort are to produce high-quality, high-resolution geologic maps and interpretations that can be utilized to identify sand resources within the region, to better understand the Holocene evolution, and to anticipate future changes in this coastal system. Processed geospatial data files and the geophysical data provided in this report help attain these goals.

Preliminary Gravity and Ground Magnetic Data in the Arbuckle Uplift near Sulphur, Oklahoma

USGS Publications Warehouse

Scheirer, Daniel S.; Aboud, Essam

2008-01-01

Improving knowledge of the geology and geophysics of the Arbuckle Uplift in south-central Oklahoma is a goal of the Framework Geology of Mid-Continent Carbonate Aquifers project sponsored by the United States Geological Survey (USGS) National Cooperative Geologic Mapping Program (NCGMP). In May 2007, we collected ground magnetic and gravity observations in the Hunton Anticline region of the Arbuckle Uplift, near Sulphur, Oklahoma. These observations complement prior gravity data collected for a project sponsored by the National Park Service and helicopter electromagnetic (HEM) and aeromagnetic data collected in March 2007 for the NCGMP project. This report describes the instrumentation and processing that was utilized in the May 2007 geophysical fieldwork, and it presents preliminary results as gravity anomaly maps and magnetic anomaly profiles. Digital tables of gravity and magnetic observations are provided as a supplement to this report. Future work will generate interpretive models of these anomalies and will involve joint analysis of these ground geophysical measurements with airborne and other geophysical and geological observations, with the goal of understanding the geological structures influencing the hydrologic properties of the Arbuckle-Simpson aquifer.

Geophysical Data Collected off the South Shore of Martha's Vineyard, Massachusetts

USGS Publications Warehouse

Denny, J.F.; Danforth, W.W.; Foster, D.S.; Sherwood, C.R.

2010-01-01

The U.S. Geological Survey Woods Hole Science Center conducted a nearshore geophysical survey offshore of the southern coast of Martha's Vineyard, in the vicinity of the Martha's Vineyard Coastal Observatory in 2007. This mapping program was part of a larger research effort supporting the Office of Naval Research Ripples Directed-Research Initiative studies at Martha's Vineyard Coastal Observatory designed to improve our understanding of coastal sediment-transport processes. The survey was conducted aboard the Megan T. Miller August 9-13, 2007. The study area covers 35 square kilometers from about 0.2 kilometers to 5 kilometers offshore of the south shore of Martha's Vineyard, and ranges in depth from ~6 to 24 meters. The geophysical mapping utilized the following suite of high-resolution instrumentation to map the surficial sediment distribution, bathymetry, and sub-surface geology: a dual-frequency 100/500 kilohertz sidescan-sonar system, 234 kilohertz interferometric sonar, and 500 hertz -12 kilohertz chirp subbottom profiler. These geophysical data will be used to provide initial conditions for wave and circulation modeling within the study area.

Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

NASA Astrophysics Data System (ADS)

Mewes, Benjamin; Hilbich, Christin; Delaloye, Reynald; Hauck, Christian

2017-12-01

Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity). Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

Reproducible Hydrogeophysical Inversions through the Open-Source Library pyGIMLi

NASA Astrophysics Data System (ADS)

Wagner, F. M.; Rücker, C.; Günther, T.

2017-12-01

Many tasks in applied geosciences cannot be solved by a single measurement method and require the integration of geophysical, geotechnical and hydrological methods. In the emerging field of hydrogeophysics, researchers strive to gain quantitative information on process-relevant subsurface parameters by means of multi-physical models, which simulate the dynamic process of interest as well as its geophysical response. However, such endeavors are associated with considerable technical challenges, since they require coupling of different numerical models. This represents an obstacle for many practitioners and students. Even technically versatile users tend to build individually tailored solutions by coupling different (and potentially proprietary) forward simulators at the cost of scientific reproducibility. We argue that the reproducibility of studies in computational hydrogeophysics, and therefore the advancement of the field itself, requires versatile open-source software. To this end, we present pyGIMLi - a flexible and computationally efficient framework for modeling and inversion in geophysics. The object-oriented library provides management for structured and unstructured meshes in 2D and 3D, finite-element and finite-volume solvers, various geophysical forward operators, as well as Gauss-Newton based frameworks for constrained, joint and fully-coupled inversions with flexible regularization. In a step-by-step demonstration, it is shown how the hydrogeophysical response of a saline tracer migration can be simulated. Tracer concentration data from boreholes and measured voltages at the surface are subsequently used to estimate the hydraulic conductivity distribution of the aquifer within a single reproducible Python script.

The Climate Variability & Predictability (CVP) Program at NOAA - Observing and Understanding Processes Affecting the Propagation of Intraseasonal Oscillations in the Maritime Continent Region

NASA Astrophysics Data System (ADS)

Lucas, S. E.

2017-12-01

The Climate Variability & Predictability (CVP) Program supports research aimed at providing process-level understanding of the climate system through observation, modeling, analysis, and field studies. This vital knowledge is needed to improve climate models and predictions so that scientists can better anticipate the impacts of future climate variability and change. To achieve its mission, the CVP Program supports research carried out at NOAA and other federal laboratories, NOAA Cooperative Institutes, and academic institutions. The Program also coordinates its sponsored projects with major national and international scientific bodies including the World Climate Research Programme (WCRP), the International and U.S. Climate Variability and Predictability (CLIVAR/US CLIVAR) Program, and the U.S. Global Change Research Program (USGCRP). The CVP program sits within NOAA's Climate Program Office (http://cpo.noaa.gov/CVP). In 2017, the CVP Program had a call for proposals focused on observing and understanding processes affecting the propagation of intraseasonal oscillations in the Maritime Continent region. This poster will present the recently funded CVP projects, the expected scientific outcomes, the geographic areas of their work in the Maritime Continent region, and the collaborations with the Office of Naval Research, Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and other partners.

COTHERM: Geophysical Modeling of High Enthalpy Geothermal Systems

NASA Astrophysics Data System (ADS)

Grab, Melchior; Maurer, Hansruedi; Greenhalgh, Stewart

2014-05-01

In recent years geothermal heating and electricity generation have become an attractive alternative energy resource, especially natural high enthalpy geothermal systems such as in Iceland. However, the financial risk of installing and operating geothermal power plants is still high and more needs to be known about the geothermal processes and state of the reservoir in the subsurface. A powerful tool for probing the underground system structure is provided by geophysical techniques, which are able to detect flow paths and fracture systems without drilling. It has been amply demonstrated that small-scale features can be well imaged at shallow depths, but only gross structures can be delineated for depths of several kilometers, where most high enthalpy systems are located. Therefore a major goal of our study is to improve geophysical mapping strategies by multi-method geophysical simulations and synthetic data inversions, to better resolve structures at greater depth, characterize the reservoir and monitor any changes within it. The investigation forms part of project COTHERM - COmbined hydrological, geochemical and geophysical modeling of geoTHERMal systems - in which a holistic and synergistic approach is being adopted to achieve multidisciplinary cooperation and mutual benefit. The geophysical simulations are being performed in combination with hydrothermal fluid flow modeling and chemical fluid rock interaction modeling, to provide realistic constraints on lithology, pressure, temperature and fluid conditions of the subsurface. Two sites in Iceland have been selected for the study, Krafla and Reykjanes. As a starting point for the geophysical modeling, we seek to establish petrophysical relations, connecting rock properties and reservoir conditions with geophysical parameters such as seismic wave speed, attenuation, electrical conductivity and magnetic susceptibility with a main focus on seismic properties. Therefore, we follow a comprehensive approach involving three components: (1) A literature study to find relevant, existing theoretical models, (2) laboratory determinations to confirm their validity for Icelandic rocks of interest and (3) a field campaign to obtain in-situ, shallow rock properties from seismic and resistivity tomography surveys over a fossilized and exhumed geothermal system. Theoretical models describing physical behavior for rocks with strong inhomogeneities, complex pore structure and complicated fluid-rock interaction mechanisms are often poorly constrained and require the knowledge about a wide range of parameters that are difficult to quantify. Therefore we calibrate the theoretical models by laboratory measurements on samples of rocks, forming magmatic geothermal reservoirs. Since the samples used in the laboratory are limited in size, and laboratory equipment operates at much higher frequency than the instruments used in the field, the results need to be up-scaled from the laboratory scale to field scale. This is not a simple process and entails many uncertainties.

Jupiter's and Saturn's ice moons: geophysical aspects and opportunities of geophysical survey of the planetary geoelectrical markers and oreols of the subsurface liquid ocean on the surface ice moons

NASA Astrophysics Data System (ADS)

Ozorovich, Yuri; Linkin, Vacheslav; Kosov, Alexandr; Fournier-Sicre, Alain; Klimov, Stanislav; Novikov, Denis; Ivanov, Anton; Skulachev, Dmitriy; Menshenin, Yaroslav

2016-04-01

This paper presents a new conceptual and methodological approach for geophysical survey of the planetary geoelectrical markers and oreols of the subsurface liquid ocean on the surface ice moons on the base "conceptual design phase" of the future space missions on the ice moons. At the design stage of such projects is considered the use of various space instruments and tools for the full the complex geophysical studies of the manifestations and planetary processes of the subsurface liquid ocean on the surface ice moons. The existence of various forms of the cryolithozone on terrestrial planets and their moons: advanced Martian permafrost zone in the form of existing of the frozen polar caps, subsurface frozen horizons, geological markers and oreols of the martian ancient (relict) ocean, subsurface oceans of Jupiter's and Saturn's moons-Europe and Enceladus, with the advanced form of permafrost freezes planetary caps, it allows to develop a common methodological basis and operational geophysical instruments (tools) for the future space program and planning space missions on these unique objects of the solar system, specialized for specific scientific problems of planetary missions. Geophysical practices and methodological principles, used in 1985-2015 by aurthors [ 1-5 ], respectively, as an example of the comprehensive geophysical experiment MARSES to study of the Martian permafrost zone and the martian ancient (relict) ocean, creating the preconditions for complex experimental setting and geo-physical monitoring of operational satellites of Jupiter and Saturn- Europe and Enceladus. This range of different planetary (like) planets with its geological history and prehistory of the common planetology formation processes of the planets formation and to define the role of a liquid ocean under the ice as a climate indicator of such planets, which is extremely important for the future construction of the geological and climatic history of the Earth. Main publications: [1]https://www.researchgate.net/publication/282151921_JUPITER%27S_MOON_EUROPA_PLANETARY_GEOELECTRICAL_MARKER_AND_OREOLS_UNDER_ICE_SUBSUEFACE_OCEAN_ON_THE_SURFACE_OF_THE_JUPITER%27S_MOON_EUROPA?ev=prf_pub [2]https://www.researchgate.net/publication/281270655_YUPITERS_MOON_EUROPA_PLANETARY_GEOELECTRICAL_MARKERS_AND_OREOPLS_OF_THE_LIQUID_OCEAN_UNDER_THE_ICE_ON_THE_SURFACE_OF_THE_YUPITERS_MOON_EUROPE [3] https://www.researchgate.net/publication/276005128_Science-technology_aspects_and_opportunities_of_em_sounding_frozen_%28_permafrost%29_soil [4]https://www.researchgate.net/publication/275638508_Cryolitozone_of_Mars_-_as_the_climatic_indicator_of_the_Martian_relict_ocean [5]https://www.researchgate.net/publication/275266762_Microwave_remote_sensing_of_Martian_cryolitozone

AIRS Maps from Space Processing Software

NASA Technical Reports Server (NTRS)

Thompson, Charles K.; Licata, Stephen J.

2012-01-01

This software package processes Atmospheric Infrared Sounder (AIRS) Level 2 swath standard product geophysical parameters, and generates global, colorized, annotated maps. It automatically generates daily and multi-day averaged colorized and annotated maps of various AIRS Level 2 swath geophysical parameters. It also generates AIRS input data sets for Eyes on Earth, Puffer-sphere, and Magic Planet. This program is tailored to AIRS Level 2 data products. It re-projects data into 1/4-degree grids that can be combined and averaged for any number of days. The software scales and colorizes global grids utilizing AIRS-specific color tables, and annotates images with title and color bar. This software can be tailored for use with other swath data products for the purposes of visualization.

Publications - GPR 2016-1 | Alaska Division of Geological & Geophysical

Science.gov Websites

Geologic Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey electromagnetic and magnetic airborne geophysical survey data compilation Authors: Burns, L.E., Fugro Airborne geophysical survey data compilation: Alaska Division of Geological & Geophysical Surveys Geophysical

Reconstructing former urban environments by combining geophysical electrical methods and geotechnical investigations—an example from Chania, Greece

NASA Astrophysics Data System (ADS)

Soupios, P. M.; Loupasakis, C.; Vallianatos, F.

2008-06-01

Nowadays, geophysical prospecting is implemented in order to resolve a diversity of geological, hydrogeological, environmental and geotechnical problems. Although plenty of applications and a lot of research have been conducted in the countryside, only a few cases have been reported in the literature concerning urban areas, mainly due to high levels of noise present that aggravate most of the geophysical methods or due to spatial limitations that hinder normal method implementation. Among all geophysical methods, electrical resistivity tomography has proven to be a rapid technique and the most robust with regard to urban noise. This work presents a case study in the urban area of Chania (Crete Island, Greece), where electrical resistivity tomography (ERT) has been applied for the detection and identification of possible buried ancient ruins or other man-made structures, prior to the construction of a building. The results of the detailed geophysical survey indicated eight areas of interest providing resistivity anomalies. Those anomalies were analysed and interpreted combining the resistivity readings with the geotechnical borehole data and the historical bibliographic reports—referring to the 1940s (Xalkiadakis 1997 Industrial Archaeology in Chania Territory pp 51-62). The collected ERT-data were processed by applying advanced algorithms in order to obtain a 3D-model of the study area that depicts the interesting subsurface structures more clearly and accurately.

Geophysical monitoring and reactive transport modeling of ureolytically-driven calcium carbonate precipitation

PubMed Central

2011-01-01

Ureolytically-driven calcium carbonate precipitation is the basis for a promising in-situ remediation method for sequestration of divalent radionuclide and trace metal ions. It has also been proposed for use in geotechnical engineering for soil strengthening applications. Monitoring the occurrence, spatial distribution, and temporal evolution of calcium carbonate precipitation in the subsurface is critical for evaluating the performance of this technology and for developing the predictive models needed for engineering application. In this study, we conducted laboratory column experiments using natural sediment and groundwater to evaluate the utility of geophysical (complex resistivity and seismic) sensing methods, dynamic synchrotron x-ray computed tomography (micro-CT), and reactive transport modeling for tracking ureolytically-driven calcium carbonate precipitation processes under site relevant conditions. Reactive transport modeling with TOUGHREACT successfully simulated the changes of the major chemical components during urea hydrolysis. Even at the relatively low level of urea hydrolysis observed in the experiments, the simulations predicted an enhanced calcium carbonate precipitation rate that was 3-4 times greater than the baseline level. Reactive transport modeling results, geophysical monitoring data and micro-CT imaging correlated well with reaction processes validated by geochemical data. In particular, increases in ionic strength of the pore fluid during urea hydrolysis predicted by geochemical modeling were successfully captured by electrical conductivity measurements and confirmed by geochemical data. The low level of urea hydrolysis and calcium carbonate precipitation suggested by the model and geochemical data was corroborated by minor changes in seismic P-wave velocity measurements and micro-CT imaging; the latter provided direct evidence of sparsely distributed calcium carbonate precipitation. Ion exchange processes promoted through NH4+ production during urea hydrolysis were incorporated in the model and captured critical changes in the major metal species. The electrical phase increases were potentially due to ion exchange processes that modified charge structure at mineral/water interfaces. Our study revealed the potential of geophysical monitoring for geochemical changes during urea hydrolysis and the advantages of combining multiple approaches to understand complex biogeochemical processes in the subsurface. PMID:21943229

NASA/MSFC FY-84 Atmospheric Processes Research Review

NASA Technical Reports Server (NTRS)

Vaughan, W. W. (Compiler); Porter, F. (Compiler)

1984-01-01

The two main areas of focus for NASA/MSFC's atmospheric research program are: (1) global scale processes (geophysical fluid processes, satellite Doppler lidar wind profiler, and satellite data analyses) and (2) mesoscale processes (atmospheric electricity (lightning), ground/airborne Doppler lidar wind measurements, and mesoscale analyses and space sensors). Topics within these two general areas are addressed.

Insights on the structural control of a Neogene forearc basin in Northern Chile: A geophysical approach

NASA Astrophysics Data System (ADS)

García-Pérez, Tiaren; Marquardt, Carlos; Yáñez, Gonzalo; Cembrano, José; Gomila, Rodrigo; Santibañez, Isabel; Maringue, José

2018-06-01

The comprehensive study of intramountain basins located in the Coastal Cordillera of the continental emergent Andean forearc in Northern Chile, enables the better understanding of the nature and evolution of the upper crustal deformation during the Neogene and Quaternary. A case study is the extensive extensional half-graben Alto Hospicio basin. The basin is cut by the Coastal Cliff, which exposes the deformed Neogene basin fill. Also exposed are several structural systems, some of which affect Quaternary surfaces. The results of the integrated geophysical surveys (Electromagnetic Transient and Gravity) allow us to fully constrain the geometry of the Alto Hospicio basin and the lithological relationship between the subsurface geological units. The structural geology analysis assesses the deformation regimes affecting the faults present in the basin and surrounding area. Altogether evidence a change in the deformation regime from an EW extensional deformation during the Miocene-Pliocene to a NS compression in the Quaternary as is presented in this study. We suggest this deformation change is related to a small change in the convergence vector orientation during the Pliocene.

Unravelling aquifer-wetland interaction using CSAMT and gravity methods: the Mollina-Camorra aquifer and the Fuente de Piedra playa-lake, southern Spain

NASA Astrophysics Data System (ADS)

Pedrera, A.; Martos-Rosillo, S.; Galindo-Zaldívar, J.; Rodríguez-Rodríguez, M.; Benavente, J.; Martín-Rodríguez, J. F.; Zúñiga-López, M. I.

2016-06-01

The hydrological regime of Fuente de Piedra playa-lake (Málaga, southern Spain) has been significantly affected by the intensive exploitation of groundwater in the area. The playa-lake is situated above clays, marls, and gypsum, and under unaltered conditions received surface-subsurface runoff within the watershed as well as groundwater discharge from two carbonate aquifers. We have analyzed the structure of the main one, the Mollina-Camorra carbonate aquifer, by combining controlled source audio magnetotellurics (CSAMT), gravity prospecting, and time-domain electromagnetic (TDEM) soundings. This geophysical information, together with new structural and hydrogeological data, was gathered to develop a new conceptual hydrogeological model. This model allows the hydrological linkage of the carbonate aquifer with the playa-lake system to be established. Moreover, the intensive exploitation in the carbonate aquifer, even outside the watershed of the playa-lake, has affected the hydrological regime of the system. This multidisciplinary work demonstrates the potential of geophysical methods for understanding wetland-aquifer interaction, having important groundwater management implications.

[Natural disasters and health: an analysis of the situation in Brazil].

PubMed

Freitas, Carlos Machado de; Silva, Diego Ricardo Xavier; Sena, Aderita Ricarda Martins de; Silva, Eliane Lima; Sales, Luiz Belino Ferreira; Carvalho, Mauren Lopes de; Mazoto, Maíra Lopes; Barcellos, Christovam; Costa, André Monteiro; Oliveira, Mara Lúcia Carneiro; Corvalán, Carlos

2014-09-01

Natural disasters are still insufficiently studied and understood within the scope of public health in this country, with impacts in the short and long term. The scope of this article is to analyze the relationship between disasters and their impact on health based on disaster data recorded in the country. The methodology involved the systematization of data and information contained in the Brazilian Atlas of Natural Disasters 1991-2010 and directly from the National Department of Civil Defense (NSCD). Disasters were organized into four categories of events (meteorological; hydrological; climatological; geophysical/geological) and for each of the latter, the data for morbidity, mortality and exposure of those affected were examined, revealing different types of impacts. Three categories of disasters stood out: the hydrological events showed higher percentages of mortality, morbidity and exposure; climatological events had higher percentages of incidents and people affected; the geophysical/geological events had a higher average of exposure and deaths per event. Lastly, a more active participation of the health sector in the post-2015 global political agenda is proposed, particularly events related to sustainable development, climate change and disaster risk reduction.

Geophysical Monitoring of Geodynamic Processes of Central Armenia Earth Crust

NASA Astrophysics Data System (ADS)

Avetyan, R.; Pashayan, R.

2016-12-01

The method of geophysical monitoring of earth crust was introduced. It allows by continuous supervision to track modern geodynamic processes of Armenia. Methodological practices of monitoring come down to allocation of a signal which reflects deformation of rocks. The indicators of deformations are not only deviations of geophysical indicators from certain background values, but also parameters of variations of these indicators. Data on changes of parameters of barometric efficiency and saw tooth oscillations of underground water level before seismic events were received. Low-amplitude periodic fluctuations of water level are the reflection of geodynamic processes taking place in upper levels of earth crust. There were recorded fluctuations of underground water level resulting from luni-solar tides and enabling to control the systems of borehole-bed in changes of voluminous deformations. The slow lowering (raising) of underground water level in the form of trend reflects long-period changes of stress-deformative state of environment. Application of method promotes identification of medium-term precursors on anomalous events of variations of geomagnetic field, change of content of subsoil radon, dynamics of level of underground water, geochemistry and water temperature. Increase of activity of geodynamic processes in Central Armenian tectonic complex is observed to change macro component Na+, Ca2+, Mg2-, CL-, SO42-, HCO3-, H4SiO4, pH and gas - CO2 structure of mineral water. Modern geodynamic movements of earth crust of Armenia are the result of seismic processes and active geodynamics of deep faults of longitudinal and transversal stretching. Key Words: monitoring, hydrogeodynamics, geomagnetic field, seismicity, deformation, earth crust

The MUTENAGE Project (MUsical Tools for ENhancing the Awareness of Global Emergencies)

NASA Astrophysics Data System (ADS)

Menghini, Antonio; Pontani, Stefano; Sapia, Vincenzo; Lanza, Tiziana

2017-04-01

Music can be a powerful device for raising awareness about environmental issues. Following the trend, we are organizing a project to specifically address climatic and environmental emergencies. To this aim, we use the transformation of geophysical data into musical notes, according to the procedure (EMusic) defined by Menghini and Pontani (2016). We claim that it is possible to compose musical tracks describing faithfully the geological and environmental setting of various sites, which we choose by considering five main topics: 1) Pollution of aquifers; 2) Seawater intrusion along the coastlines; 3) Seismic risk; 4) Drought; 5) Permafrost melting; The TDEM method (Time Domain Electromagnetics) shows an excellent diagnostic feature for each of these environmental emergencies. It is not surprising that the technical-scientific community widely acquire TDEM data since many years as the variations of the recorded signal (voltage) duly reflect the modifications induced on the Earth system. Through the sonification process, we can associate well-defined musical "footprints" to these geophysical variations. Then, we have an extraordinary didactic-popular tool that we can use to communicate and sensitize people and students of every age and grade about the impact of climatic-environmental changes. In this occasion, we present, among others, the example of the musical effect of seawater intrusion that is well marked by the progressive increase of the pitches when approaching the coastline. In many cases, the relationship between geophysical response and high environmental risk is straight: for instance, pollutants, like leachate or polluted groundwater, can produce high voltage responses and/or similar high voltage signals can be produced by soils affected by permafrost melting. Nevertheless, there are situations in which the diagnostic feature of TDEM is fair, however, even if the data interpretation is less immediate, so that it requires an accurate processing and inversion of the data. In these cases, the sonification significantly contribute to make comprehensible less intense geophysical variations. As such, the seismic risk assessment is a valid example. It is possible to let "hear" the differences among the existing geological units, which may contribute to different seismic amplification and thus leading to diverse level of risk. The same is valid for the study of the hydrogeological critical issues, where the sound of an aquifer can be very different from that of an impermeable zone. Besides being a new source of inspiration for musicians, the MUTENAGE Project is intended for delivering original didactic tools for scientific museums and schools. As such, we are also planning a series of EM concerts that will be located in different countries, for each of the above-mentioned environmental issues. References Menghini, A., and Pontani, S., (2016): What is the Sound of the Earth? First Break, 34, 41-46.

Ecosystem Services and Climate Change Considerations for Long Island (NY) Planning Post Hurricane Sandy

EPA Science Inventory

Freshwater habitats provide fishable, swimmable and drinkable resources and are a nexus of geophysical and biological processes. These processes in turn influence the persistence and sustainability of populations, communities and ecosystems. Climate change and landuse change enco...

Under the pile. Understanding subsurface dynamics of historical cities trough geophysical models interpretation

NASA Astrophysics Data System (ADS)

Bernardes, Paulo; Pereira, Bruno; Alves, Mafalda; Fontes, Luís; Sousa, Andreia; Martins, Manuela; Magalhães, Fernanda; Pimenta, Mário

2017-04-01

Braga is one of the oldest cities of the Iberian NW and as of so, the research team's studying the city's historical core for the past 40 years is often confronted with the unpredictability factor laying beneath an urban site with such a long construction history. In fact, Braga keeps redesigning its urban structure over itself on for the past 2000 years, leaving us with a research object filled with an impressive set of construction footprints from the various planning decisions that were taken in the city along its historical path. Aiming for a predicting understanding of the subsoil, we have used near surface geophysics as an effort of minimizing the areas of intervention for traditional archaeological survey techniques. The Seminário de Santiago integrated geophysical survey is an example of the difficulties of interpreting geophysical models in very complex subsurface scenarios. This geophysical survey was planned in order to aid the requalification project being designed for this set of historical buildings, that are estimated to date back to the 16h century, and that were built over one of the main urban arteries of both roman and medieval layers of Braga. We have used both GPR as well as ERT methods for the geophysical survey, but for the purpose of this article, we will focus in the use of the ERT alone. For the interpretation of the geophysical models we've cross-referenced the dense knowledge existing over the building's construction phases with the complex geophysical data collected, using mathematical processing and volume-based visualization techniques, resorting to the use of Res2Inv©, Paraview© and Voxler® software's. At the same time we tried to pinpoint the noise caused by the past 30 year's infrastructural interventions regarding the replacement of the building's water and sanitation systems and for which we had no design plants, regardless of its recent occurring. The deep impact of this replacement actions revealed by the archaeological trenches, which location was selected from the results of the geophysical models interpretation, revealed to be our main unpredictability factor and, paradoxically, one of its principal results, as it will allow us to be more interpretation efficient in future geophysical surveys in the historical core. As for so, at the present we are designing an integrated geophysical research programme that will hold Braga's historical subsurface as it's open lab, aiming to develop a tool not only for archeologists and geophysicists, but also and foremost to help the city planners to design more informed, efficient and sustainable urban plans for Braga, as the city is very much alive and continually keeps on adding new layers to its urban structure.

Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) PARM tape user's guide

NASA Technical Reports Server (NTRS)

Han, D.; Gloersen, P.; Kim, S. T.; Fu, C. C.; Cebula, R. P.; Macmillan, D.

1992-01-01

The Scanning Multichannel Microwave Radiometer (SMMR) instrument, onboard the Nimbus-7 spacecraft, collected data from Oct. 1978 until Jun. 1986. The data were processed to physical parameter level products. Geophysical parameters retrieved include the following: sea-surface temperatures, sea-surface windspeed, total column water vapor, and sea-ice parameters. These products are stored on PARM-LO, PARM-SS, and PARM-30 tapes. The geophysical parameter retrieval algorithms and the quality of these products are described for the period between Nov. 1978 and Oct 1985. Additionally, data formats and data availability are included.

Institute of Geophysics and Planetary Physics (IGPP), Lawrence Livermore National Laboratory (LLNL): Quinquennial report, November 14-15, 1996

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

Tweed, J.

1996-10-01

This Quinquennial Review Report of the Lawrence Livermore National Laboratory (LLNL) branch of the Institute for Geophysics and Planetary Physics (IGPP) provides an overview of IGPP-LLNL, its mission, and research highlights of current scientific activities. This report also presents an overview of the University Collaborative Research Program (UCRP), a summary of the UCRP Fiscal Year 1997 proposal process and the project selection list, a funding summary for 1993-1996, seminars presented, and scientific publications. 2 figs., 3 tabs.

Integration of Field Geophysics and Geology in an International Setting: Multidisciplinary Geoscience Field Experience at the University of Western Ontario

NASA Astrophysics Data System (ADS)

Brenders, A. J.; Banerjee, N.; Pratt, R. G.

2010-12-01

The pedagogical value of the field experience is unequaled: students, teaching assistants, and professors alike return with a renewed sense of purpose, community, and the context in which to place classroom education. It is widely regarded as valuable to personal development, and is required by the Canadian Council of Professional Geoscientists for professional registration. As part of our ongoing International Geoscience Field Experience Initiative, Earth Sciences students at the University of Western Ontario have the opportunity to enhance their education through a study abroad program. The focus is on a residential field experience to world-class localities, offered with the collaboration of internationally recognized academic researchers, government survey personnel, and industry leaders. Recent trips have included the Sn-W mineralization in the Cornwall district of the U.K., the Iberian Pyrite Belt (IPB) in Portugal and Spain, and the metallogenic belts of Western Turkey. The integration of geological knowledge with geophysical data was one of the key organizing principles of our recent field trips to the IPB and Western Turkey. This integration is a foundation of modern Earth Sciences, and common practice in industry, it is relatively rare in classroom settings. Lectures before departure and evening exercises during the field trip supplemented the core undergraduate curriculum in geophysics, reviewing gravity, DC resistivity, induced polarization (IP), and magnetotelluric methods, focusing on application to mineral exploration. During our trip to the IPB, partnership with industry allowed students the opportunity to work with state of the art geophysical data, acquired on an exploration prospect visited during the field trip. Multi-parameter geophysical inversions of the IP and MT data produced cross-sections in depth - results interpretable by the students in the complex geological environment of the Iberian Pyrite Belt. Although the students gained valuable geological insight, the lack of practical experience in the acquisition and processing of geophysical data was identified in course evaluations. To address this, in Western Turkey, students had the opportunity to design and acquire total magnetic field surveys using a walking magnetometer, combining a GPS receiver and proton-precession magnetometer. Using this instrument, students identified the geophysical response of subsurface features, visible in both outcrop and during traverse through open pit mines. A transect across a buried basalt - limestone contact was made, and the strike of the contact identified during subsequent data processing. Students also had the opportunity to visit an active IP-resistivity survey, observing the acquisition of this data in the field, and learn how project geologists integrate this data with geological drill cores. Finally, students designed and acquired a total magnetic field survey over an archaeological site: the Acropolis at Pergamon. By integrating data acquisition, processing, and interpretation with field visits to sites of both geological and archaeological interest, students acquired field and technical skills that ideally prepared them for a future in research or industry.

An iterative particle filter approach for coupled hydro-geophysical inversion of a controlled infiltration experiment

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

Manoli, Gabriele, E-mail: manoli@dmsa.unipd.it; Nicholas School of the Environment, Duke University, Durham, NC 27708; Rossi, Matteo

The modeling of unsaturated groundwater flow is affected by a high degree of uncertainty related to both measurement and model errors. Geophysical methods such as Electrical Resistivity Tomography (ERT) can provide useful indirect information on the hydrological processes occurring in the vadose zone. In this paper, we propose and test an iterated particle filter method to solve the coupled hydrogeophysical inverse problem. We focus on an infiltration test monitored by time-lapse ERT and modeled using Richards equation. The goal is to identify hydrological model parameters from ERT electrical potential measurements. Traditional uncoupled inversion relies on the solution of two sequentialmore » inverse problems, the first one applied to the ERT measurements, the second one to Richards equation. This approach does not ensure an accurate quantitative description of the physical state, typically violating mass balance. To avoid one of these two inversions and incorporate in the process more physical simulation constraints, we cast the problem within the framework of a SIR (Sequential Importance Resampling) data assimilation approach that uses a Richards equation solver to model the hydrological dynamics and a forward ERT simulator combined with Archie's law to serve as measurement model. ERT observations are then used to update the state of the system as well as to estimate the model parameters and their posterior distribution. The limitations of the traditional sequential Bayesian approach are investigated and an innovative iterative approach is proposed to estimate the model parameters with high accuracy. The numerical properties of the developed algorithm are verified on both homogeneous and heterogeneous synthetic test cases based on a real-world field experiment.« less

The discovery and geophysical response of the Atlántida Cu-Au porphyry deposit, Chile

NASA Astrophysics Data System (ADS)

Hope, Matthew; Andersson, Steve

2016-03-01

The discovery of the Atlántida Cu-Au-Mo porphyry deposit, which is unconformably overlain by 25-80 m of gravels, is a recent example of exploration success under cover in a traditional mining jurisdiction. Early acquisition of geophysics was a key tool in the discovery, and in later guiding further exploration drilling throughout the life of the project. Detailed review of the geophysical response of the deposit, with respect to the distribution of lithologies and alteration, coupled with their petrophysical properties has allowed full characterisation, despite no exposure at the surface of host rock nor porphyry-style mineralisation. Data acquired over the project include induced polarisation, magnetotellurics, ground and airborne magnetics, ground-based gravimetry, and petrophysical sampling. The distribution of the key geological features of the deposit has been inferred via acquisition of petrophysical properties and interpretation of surface geophysical datasets. Magnetic susceptibility is influenced strongly by both alteration and primary lithology, whilst density variations are dominated by primary lithological control. Several studies have shown that electrical properties may map the footprint of the hydrothermal system and associated mineralisation, via a combination of chargeability and resistivity. These properties are observed in geophysical datasets acquired at surface and allow further targeting and sterilisation at the deposit and project scale. By understanding these geophysical characteristics in a geological context, these data can be used to infer distribution of lithological units, depth to exploration targets and the potential for high grade mineralisation. Future exploration will likely be increasingly reliant on the understanding of the surface manifestations of buried deposits in remotely acquired data. This review summarises the application and results of these principles at the Atlántida project of northern Chile. Geophysical data can be used to improve the chances of discovery beneath post-mineral cover, and also improve drilling results throughout the advanced exploration of the program. The process of data review against geological control information is essential.

Practices to enable the geophysical research spectrum: from fundamentals to applications

NASA Astrophysics Data System (ADS)

Kang, S.; Cockett, R.; Heagy, L. J.; Oldenburg, D.

2016-12-01

In a geophysical survey, a source injects energy into the earth and a response is measured. These physical systems are governed by partial differential equations and their numerical solutions are obtained by discretizing the earth. Geophysical simulations and inversions are tools for understanding physical responses and constructing models of the subsurface given a finite amount of data. SimPEG (http://simpeg.xyz) is our effort to synthesize geophysical forward and inverse methodologies into a consistent framework. The primary focus of our initial development has been on the electromagnetics (EM) package, with recent extensions to magnetotelluric, direct current (DC), and induced polarization. Across these methods, and applied geophysics in general, we require tools to explore and build an understanding of the physics (behaviour of fields, fluxes), and work with data to produce models through reproducible inversions. If we consider DC or EM experiments, with the aim of understanding responses from subsurface conductors, we require resources that provide multiple "entry points" into the geophysical problem. To understand the physical responses and measured data, we must simulate the physical system and visualize electric fields, currents, and charges. Performing an inversion requires that many moving pieces be brought together: simulation, physics, linear algebra, data processing, optimization, etc. Each component must be trusted, accessible to interrogation and manipulation, and readily combined in order to enable investigation into inversion methodologies. To support such research, we not only require "entry points" into the software, but also extensibility to new situations. In our development of SimPEG, we have sought to use leading practices in software development with the aim of supporting and promoting collaborations across a spectrum of geophysical research: from fundamentals to applications. Designing software to enable this spectrum puts unique constraints on both the architecture of the codebase as well as the development practices that are employed. In this presentation, we will share some lessons learned and, in particular, how our prioritization of testing, documentation, and refactoring has impacted our own research and fostered collaborations.

Learning about hydrothermal volcanic activity by modeling induced geophysical changes

NASA Astrophysics Data System (ADS)

Currenti, Gilda M.; Napoli, Rosalba

2017-05-01

Motivated by ongoing efforts to understand the nature and the energy potential of geothermal resources, we devise a coupled numerical model (hydrological, thermal, mechanical), which may help in the characterization and monitoring of hydrothermal systems through computational experiments. Hydrothermal areas in volcanic regions arise from a unique combination of geological and hydrological features which regulate the movement of fluids in the vicinity of magmatic sources capable of generating large quantities of steam and hot water. Numerical simulations help in understanding and characterizing rock-fluid interaction processes and the geophysical observations associated with them. Our aim is the quantification of the response of different geophysical observables (i.e. deformation, gravity and magnetic field) to hydrothermal activity on the basis of a sound geological framework (e.g. distribution and pathways of the flows, the presence of fractured zones, caprock). A detailed comprehension and quantification of the evolution and dynamics of the geothermal systems and the definition of their internal state through a geophysical modeling approach are essential to identify the key parameters for which the geothermal system may fulfill the requirements to be exploited as a source of energy. For the sake of illustration only, the numerical computations are focused on a conceptual model of the hydrothermal system of Vulcano Island by simulating a generic 1-year unrest and estimating different geophysical changes. We solved (i) the mass and energy balance equations of flow in porous media for temperature, pressure and density changes, (ii) the elastostatic equation for the deformation field and (iii) the Poisson’s equations for gravity and magnetic potential fields. Under the model assumptions, a generic unrest of 1-year engenders on the ground surface low amplitude changes in the investigated geophysical observables, that are, however, above the accuracies of the modern state-of-the-art instruments. Devising multidisciplinary and easy-to-use computational experiments enable us to learn how the hydrothermal system responds to un unrest and which fingerprints it may leave in the geophysical signals.

R/V Kilo Moana's New Geophysical Instrumentation, Processing Methods, and Online Data Repository

NASA Astrophysics Data System (ADS)

Miller, J. E.; Chandler, M. T.; Taylor, B.; Shor, A.; Ferguson, J. S.; Wessel, P.

2012-12-01

In 2012 several upgrades were made to the underway geophysical systems on R/V Kilo Moana, which the University of Hawaii School of Ocean and Earth Science and Technology (SOEST) operates as part of the University-National Oceanographic Laboratory System (UNOLS) fleet. New instrumentation includes a Bell BGM-3 forced feedback-type gravimeter, a Kongsberg EM 122 12-kHz receiver array, and a high resolution 70-100 kHz EM 710 multibeam echo sounder. Multibeam acceptance trials carried out in June by the Multibeam Advisory Committee, Gates Acoustic Services and UH-SOEST found that both sonars are performing within expected levels with ~5x water depth (WD) for the EM 710 system in shallow water and ~19 km swath width at 4,700 m depth (~4x WD) for the EM 122 deep water system. UH-SOEST also took steps this year to fulfill its obligation to make Kilo Moana's geophysical data more accessible to the public. After an audit of Kilo Moana data at SOEST, Lamont's Rolling Deck to Repository (R2R) and the National Geophysical Data Center (NGDC), as of July 2012 all National Science Foundation-funded Kilo Moana multibeam, gravity, magnetics, center beam depth and Acoustic Doppler Current Profiler (ADCP) data have been submitted to R2R and any multibeam data over 2 years old is being transferred to NGDC. Because it had previously been difficult to access some of SOEST's geophysical data, updated data processing routines have been developed for converting raw gravity, magnetics, and centerbeam depth data to NGDC's standard marine data exchange format (MGD77) for archival and dissemination by NGDC. MGD77 files are being generated and inspected using rigorous along-track analytical techniques for ~270 surveys dating from 2002 to the present and are being submitted to NGDC. We are also developing an online data portal to further facilitate access to SOEST data.

The efficiency of geophysical adjoint codes generated by automatic differentiation tools

NASA Astrophysics Data System (ADS)

Vlasenko, A. V.; Köhl, A.; Stammer, D.

2016-02-01

The accuracy of numerical models that describe complex physical or chemical processes depends on the choice of model parameters. Estimating an optimal set of parameters by optimization algorithms requires knowledge of the sensitivity of the process of interest to model parameters. Typically the sensitivity computation involves differentiation of the model, which can be performed by applying algorithmic differentiation (AD) tools to the underlying numerical code. However, existing AD tools differ substantially in design, legibility and computational efficiency. In this study we show that, for geophysical data assimilation problems of varying complexity, the performance of adjoint codes generated by the existing AD tools (i) Open_AD, (ii) Tapenade, (iii) NAGWare and (iv) Transformation of Algorithms in Fortran (TAF) can be vastly different. Based on simple test problems, we evaluate the efficiency of each AD tool with respect to computational speed, accuracy of the adjoint, the efficiency of memory usage, and the capability of each AD tool to handle modern FORTRAN 90-95 elements such as structures and pointers, which are new elements that either combine groups of variables or provide aliases to memory addresses, respectively. We show that, while operator overloading tools are the only ones suitable for modern codes written in object-oriented programming languages, their computational efficiency lags behind source transformation by orders of magnitude, rendering the application of these modern tools to practical assimilation problems prohibitive. In contrast, the application of source transformation tools appears to be the most efficient choice, allowing handling even large geophysical data assimilation problems. However, they can only be applied to numerical models written in earlier generations of programming languages. Our study indicates that applying existing AD tools to realistic geophysical problems faces limitations that urgently need to be solved to allow the continuous use of AD tools for solving geophysical problems on modern computer architectures.

30 CFR 251.13 - Reimbursement for the costs of reproducing data and information and certain processing costs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and information and certain processing costs. 251.13 Section 251.13 Mineral Resources MINERALS... third party for the reasonable costs of processing geophysical information (which does not include cost... OUTER CONTINENTAL SHELF § 251.13 Reimbursement for the costs of reproducing data and information and...

Learning and Information Approaches for Inference in Dynamic Data-Driven Geophysical Applications

NASA Astrophysics Data System (ADS)

Ravela, S.

2015-12-01

Many Geophysical inference problems are characterized by non-linear processes, high-dimensional models and complex uncertainties. A dynamic coupling between models, estimation, and sampling is typically sought to efficiently characterize and reduce uncertainty. This process is however fraught with several difficulties. Among them, the key difficulties are the ability to deal with model errors, efficacy of uncertainty quantification and data assimilation. In this presentation, we present three key ideas from learning and intelligent systems theory and apply them to two geophysical applications. The first idea is the use of Ensemble Learning to compensate for model error, the second is to develop tractable Information Theoretic Learning to deal with non-Gaussianity in inference, and the third is a Manifold Resampling technique for effective uncertainty quantification. We apply these methods, first to the development of a cooperative autonomous observing system using sUAS for studying coherent structures. We apply this to Second, we apply this to the problem of quantifying risk from hurricanes and storm surges in a changing climate. Results indicate that learning approaches can enable new effectiveness in cases where standard approaches to model reduction, uncertainty quantification and data assimilation fail.

Monitoring spatial and temporal variations of permeability in constructed wetlands by time-lapse geophysical methods

NASA Astrophysics Data System (ADS)

Tapias, J. C.; Himi, M.; Lovera, R.; Blasco, R.; Folch, M.; Casas, A.

2012-04-01

Constructed wetlands are widely used for removing pollutants from wastewater in small communities because their simplicity and low operation costs. Nevertheless, with time the cleaning process can result in gradual clogging of the porous layer by suspended solids, bacterial film, chemical precipitates and compactation. The clogging development causes decrease of hydraulic conductivity, reduced oxygen supply and further leads to a rapid decrease of the treatment performance. As the investment involved in reversing clogging can represent a substantial fraction of the cost of a new system it is essential to assess in advance the evolution of clogging process and detect potential failures in the system. Since there is a lack of experiences for monitoring the functionality of constructed wedlands a combination of non-destructive geophysical methods have been tested in this study. With this purpose electrical resistivity tomography, induced polarisation, frequency domain EM and ground probing radar have been conducted at different horizontal subsurface flow municipal wastewater treatment wetlands of Catalonia (Spain). The obtained results have shown that the applied geophysical techniques may delineate the clogging expansion and help take the preventive measures for enlarge the lifetime of the treatment system.

Mapping porosity of the deep critical zone in 3D using near-surface geophysics, rock physics modeling, and drilling

NASA Astrophysics Data System (ADS)

Flinchum, B. A.; Holbrook, W. S.; Grana, D.; Parsekian, A.; Carr, B.; Jiao, J.

2017-12-01

Porosity is generated by chemical, physical and biological processes that work to transform bedrock into soil. The resulting porosity structure can provide specifics about these processes and can improve understanding groundwater storage in the deep critical zone. Near-surface geophysical methods, when combined with rock physics and drilling, can be a tool used to map porosity over large spatial scales. In this study, we estimate porosity in three-dimensions (3D) across a 58 Ha granite catchment. Observations focus on seismic refraction, downhole nuclear magnetic resonance logs, downhole sonic logs, and samples of core acquired by push coring. We use a novel petrophysical approach integrating two rock physics models, a porous medium for the saprolite and a differential effective medium for the fractured rock, that drive a Bayesian inversion to calculate porosity from seismic velocities. The inverted geophysical porosities are within about 0.05 m3/m3 of lab measured values. We extrapolate the porosity estimates below seismic refraction lines to a 3D volume using ordinary kriging to map the distribution of porosity in 3D up to depths of 80 m. This study provides a unique map of porosity on scale never-before-seen in critical zone science. Estimating porosity on these large spatial scales opens the door for improving and understanding the processes that shape the deep critical zone.

Geophysical study of the structure and processes of the continental convergence zones: Alpine-Himalayan belt

NASA Technical Reports Server (NTRS)

Toksoz, M. N.; Molnar, P.

1983-01-01

Studies of the structure of the continental collision zones using seismic and body waves, theoretical modelling of the thermal regime of the convergence processes, and studies of earthquake mechanisms and deformation aspects of the model are covered.

Whether weather affects music

NASA Astrophysics Data System (ADS)

Aplin, Karen L.; Williams, Paul D.

2012-09-01

The creative output of composers, writers, and artists is often influenced by their surroundings. To give a literary example, it has been claimed recently that some of the characters in Oliver Twist and A Christmas Carol were based on real-life people who lived near Charles Dickens in London [Richardson, 2012]. Of course, an important part of what we see and hear is not only the people with whom we interact but also our geophysical surroundings. Of all the geophysical phenomena to influence us, the weather is arguably the most significant because we are exposed to it directly and daily. The weather was a great source of inspiration for artists Claude Monet, John Constable, and William Turner, who are known for their scientifically accurate paintings of the skies [e.g., Baker and Thornes, 2006].

Considerations for ICRF-3

NASA Astrophysics Data System (ADS)

Ma, Chopo; MacMillan, Daniel; Gordon, David

2015-08-01

The Second Realization of the International Celestial Reference Frame (ICRF) used dual-frequency VLBI data acquired for geodetic and astrometric purposes from 1979-2009 by organizations now coordinated by the International VLBI Service for Geodesy and Astrometry (IVS) and analyzed according to the Conventions of the International Earth Rotation and Reference Systems Service (IERS). Since 2009 the data set has been significantly broadened, especially by observations in the Southern Hemisphere, and modeling of astronomical, geophysical and tropospheric effects has progressed. The new southern data appear to cause a systematic zonal declination change in the catalog positions. Over the three decades of the ICRF data set the effect of galactic aberration may be significant. Geophysical and tropospheric models also may affect the source positions. All these effects need to be addressed in preparation for ICRF-3.

The Research on Borehole Stability in Depleted Reservoir and Caprock: Using the Geophysics Logging Data

PubMed Central

Deng, Jingen; Luo, Yong; Guo, Shisheng; Zhang, Haishan; Tan, Qiang; Zhao, Kai; Hu, Lianbo

2013-01-01

Long-term oil and gas exploitation in reservoir will lead to pore pressure depletion. The pore pressure depletion will result in changes of horizontal in-situ stresses both in reservoirs and caprock formations. Using the geophysics logging data, the magnitude and orientation changes of horizontal stresses in caprock and reservoir are studied. Furthermore, the borehole stability can be affected by in-situ stresses changes. To address this issue, the dehydration from caprock to reservoir and roof effect of caprock are performed. Based on that, the influence scope and magnitude of horizontal stresses reduction in caprock above the depleted reservoirs are estimated. The effects of development on borehole stability in both reservoir and caprock are studied step by step with the above geomechanical model. PMID:24228021

Geophysical analysis for the Ada Tepe region (Bulgaria) - case study

NASA Astrophysics Data System (ADS)

Trifonova, Petya; Metodiev, Metodi; Solakov, Dimcho; Simeonova, Stela; Vatseva, Rumiana

2013-04-01

According to the current archeological investigations Ada Tepe is the oldest gold mine in Europe with Late Bronze and Early Iron age. It is a typical low-sulfidation epithermal gold deposit and is hosted in Maastrichtian-Paleocene sedimentary rocks above a detachment fault contact with underlying Paleozoic metamorphic rocks. Ada Tepe (25o.39'E; 41o.25'N) is located in the Eastern Rhodope unit. The region is highly segmented despite the low altitude (470-750 m) due to widespread volcanic and sediment rocks susceptible to torrential erosion during the cold season. Besides the thorough geological exploration focused on identifying cost-effective stocks of mineral resources, a detailed geophysical analysis concernig diferent stages of the gold extraction project was accomplished. We present the main results from the geophysical investigation aimed to clarify the complex seismotectonic setting of the Ada Tepe site region. The overall study methodology consists of collecting, reviewing and estimating geophysical and seismological information to constrain the model used for seismic hazard assessment of the area. Geophysical information used in the present work consists of gravity, geomagnetic and seismological data. Interpretation of gravity data is applied to outline the axes of steep gravity transitions marked as potential axes of faults, flexures and other structures of dislocation. Direct inverse techniques are also utilized to estimate the form and depth of anomalous sources. For the purposes of seismological investigation of the Ada Tepe site region an earthquake catalogue is compiled for the time period 510BC - 2011AD. Statistical parameters of seismicity - annual seismic rate parameter, ?, and the b-value of the Gutenberg-Richter exponential relation for Ada Tepe site region, are estimated. All geophysical datasets and derived results are integrated using GIS techniques ensuring interoperability of data when combining, processing and visualizing obtained information from different sources.

Geophysical monitoring in a hydrocarbon reservoir

NASA Astrophysics Data System (ADS)

Caffagni, Enrico; Bokelmann, Goetz

2016-04-01

Extraction of hydrocarbons from reservoirs demands ever-increasing technological effort, and there is need for geophysical monitoring to better understand phenomena occurring within the reservoir. Significant deformation processes happen when man-made stimulation is performed, in combination with effects deriving from the existing natural conditions such as stress regime in situ or pre-existing fracturing. Keeping track of such changes in the reservoir is important, on one hand for improving recovery of hydrocarbons, and on the other hand to assure a safe and proper mode of operation. Monitoring becomes particularly important when hydraulic-fracturing (HF) is used, especially in the form of the much-discussed "fracking". HF is a sophisticated technique that is widely applied in low-porosity geological formations to enhance the production of natural hydrocarbons. In principle, similar HF techniques have been applied in Europe for a long time in conventional reservoirs, and they will probably be intensified in the near future; this suggests an increasing demand in technological development, also for updating and adapting the existing monitoring techniques in applied geophysics. We review currently available geophysical techniques for reservoir monitoring, which appear in the different fields of analysis in reservoirs. First, the properties of the hydrocarbon reservoir are identified; here we consider geophysical monitoring exclusively. The second step is to define the quantities that can be monitored, associated to the properties. We then describe the geophysical monitoring techniques including the oldest ones, namely those in practical usage from 40-50 years ago, and the most recent developments in technology, within distinct groups, according to the application field of analysis in reservoir. This work is performed as part of the FracRisk consortium (www.fracrisk.eu); this project, funded by the Horizon2020 research programme, aims at helping minimize the environmental footprint of the shale-gas exploration and exploitation.

Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring, SoilCAM project highlights

NASA Astrophysics Data System (ADS)

French, H. K.; Van Der Zee, S. E.; Wehrer, M.; Godio, A.; Pedersen, L. B.; Tsocano, G.

2013-12-01

The SoilCAM project (2008- 2012, EU-FP7-212663) aimed at improving methods for monitoring subsurace contaminant distribution and biodegradation. Two test sites were chosen, Oslo airport Gardermoen, Norway where de-icing agents infiltrate the soil during snowmelt and the Trecate site in Italy where an inland crude oil spill occurred in 1994. A number of geophysical investigation techniques were combined with soil and water sampling techniques. Data obtained from time-lapse measurements were further analysed by numerical modelling of flow and transport at different scales in order to characterise transport processes in the unsaturated and saturated zones. Laboratory experiments provided physical and biogeochemical data for model parameterisation and to select remediation methods. The geophysical techniques were used to map geological heterogeneities and to conduct time-lapse measurements of processes in the unsaturated zone. Both cross borehole and surface electrodes were used for electrical resistivity and induced polarisation surveys. Results showed clear indications of areas highly affected by de-icing chemicals along the runway at Oslo airport. The time lapse measurements along the runway at the airport showed infiltration patterns during snowmelt and were used to validate 2D unsaturated flow and transport simulations using SUTRA. The simulations illustrate the effect of layering geological structures and membranes, buried parallel to the runway, on the flow pattern. Complex interaction between bio-geo-chemical processes in a 1D vertical profile along the runway were described with the ORCHESTRA model. Smaller scale field site measurements revealed increase of iron and manganese during degradation of de-icing chemicals. At the Trecate site a combination of georadar, electrical resistivity and radio magneto telluric provided a broad outline of the geology down to 50 m. Anomalies in the Induced polarisation and electrical resistivity data from the cross borehole measurements indicate where the remaining crude oil can be found. Water samples from multilevel samplers reveal crude oil present in emulsion in the zone of groundwater fluctuations, highlighting the importance of colloidal transport. Modelling of multiphase flow of the fluctuating groundwater level explains the lack of horizontal displacement of the plume in the area. Geochemistry of the groundwater clearly indicates degradation of hydrocarbons under iron- and sulphate reducing conditions, but changes were too slow to be mapped by time-lapse geophysical measurements during the project period. MODFLOW was used to simulate the regional groundwater flow and transport in the area. Highlights of the results from both test sites will be presented as an integrated overview. Snow removal at Oslo airport

A framework for testing the use of electric and electromagnetic data to reduce the prediction error of groundwater models

NASA Astrophysics Data System (ADS)

Christensen, N. K.; Christensen, S.; Ferre, T. P. A.

2015-09-01

Despite geophysics is being used increasingly, it is still unclear how and when the integration of geophysical data improves the construction and predictive capability of groundwater models. Therefore, this paper presents a newly developed HYdrogeophysical TEst-Bench (HYTEB) which is a collection of geological, groundwater and geophysical modeling and inversion software wrapped to make a platform for generation and consideration of multi-modal data for objective hydrologic analysis. It is intentionally flexible to allow for simple or sophisticated treatments of geophysical responses, hydrologic processes, parameterization, and inversion approaches. It can also be used to discover potential errors that can be introduced through petrophysical models and approaches to correlating geophysical and hydrologic parameters. With HYTEB we study alternative uses of electromagnetic (EM) data for groundwater modeling in a hydrogeological environment consisting of various types of glacial deposits with typical hydraulic conductivities and electrical resistivities covering impermeable bedrock with low resistivity. It is investigated to what extent groundwater model calibration and, often more importantly, model predictions can be improved by including in the calibration process electrical resistivity estimates obtained from TEM data. In all calibration cases, the hydraulic conductivity field is highly parameterized and the estimation is stabilized by regularization. For purely hydrologic inversion (HI, only using hydrologic data) we used Tikhonov regularization combined with singular value decomposition. For joint hydrogeophysical inversion (JHI) and sequential hydrogeophysical inversion (SHI) the resistivity estimates from TEM are used together with a petrophysical relationship to formulate the regularization term. In all cases, the regularization stabilizes the inversion, but neither the HI nor the JHI objective function could be minimized uniquely. SHI or JHI with regularization based on the use of TEM data produced estimated hydraulic conductivity fields that bear more resemblance to the reference fields than when using HI with Tikhonov regularization. However, for the studied system the resistivities estimated by SHI or JHI must be used with caution as estimators of hydraulic conductivity or as regularization means for subsequent hydrological inversion. Much of the lack of value of the geophysical data arises from a mistaken faith in the power of the petrophysical model in combination with geophysical data of low sensitivity, thereby propagating geophysical estimation errors into the hydrologic model parameters. With respect to reducing model prediction error, it depends on the type of prediction whether it has value to include geophysical data in the model calibration. It is found that all calibrated models are good predictors of hydraulic head. When the stress situation is changed from that of the hydrologic calibration data, then all models make biased predictions of head change. All calibrated models turn out to be a very poor predictor of the pumping well's recharge area and groundwater age. The reason for this is that distributed recharge is parameterized as depending on estimated hydraulic conductivity of the upper model layer which tends to be underestimated. Another important insight from the HYTEB analysis is thus that either recharge should be parameterized and estimated in a different way, or other types of data should be added to better constrain the recharge estimates.

Analysis and interpretation of geophysical surveys in archaeological sites employing different integrated approach.

NASA Astrophysics Data System (ADS)

Piro, Salvatore; Papale, Enrico; Kucukdemirci, Melda; Zamuner, Daniela

2017-04-01

Non-destructive ground surface geophysical prospecting methods are frequently used for the investigation of archaeological sites, where a detailed physical and geometrical reconstructions of hidden volumes is required prior to any excavation work. All methods measure the variations of single physical parameters, therefore if these are used singularly, they could not permit a complete location and characterization of anomalous bodies. The probability of a successful result rapidly increases if a multhimethodological approach is adopted, according to the logic of objective complementarity of information and of global convergence toward a high quality multiparametric imaging of the buried structures. The representation of the static configuration of the bodies in the subsoil and of the space-time evolution of the interaction processes between targets and hosting materials have to be actually considered fundamental elements of primary knowledge in archaeological prospecting. The main effort in geophysical prospecting for archaeology is therefore the integration of different, absolutely non-invasive techniques, especially if managed in view of a ultra-high resolution three-dimensional (3D) tomographic representation mode. Following the above outlined approach, we have integrated geophysical methods which measure the variations of potential field (gradiometric methods) with active methods which measure the variations of physical properties due to the body's geometry and volume (GPR and ERT). In this work, the results obtained during the surveys of three archaeological sites, employing Ground Penetrating Radar (GPR), Electrical Resistivity Tomography (ERT) and Fluxgate Differential Magnetic (FDM) to obtain precise and detailed maps of subsurface bodies, are presented and discussed. The first site, situated in a suburban area between Itri and Fondi, in the Aurunci Natural Regional Park (Central Italy), is characterized by the presence of remains of past human activity dating from the third century B.C. The second site is always in suburban area and is part of the ancient acropolis Etruscan town of Cerveteri (central Italy). The third site is part of Aizanoi archaeological park (Cavdarhisar, Kutahya, Turkey). To have a better understanding of the subsurface, we performed a different integrated approaches of these data, which consists in fusing the data from all the employed methods, to have a complete visualization of the investigated area. For the processing we have used the following techniques: graphical integration (overlay and RGB colour composite), discrete data analysis (binary data analysis and cluster analysis) and continuous data analysis (data sum, product, max, min and PCA). Ernenwein, E.G. 2009. Integration of multidimensional archaeogeophysical data using supervised and unsupervised classification. Near surface geophysics. Vol 7: 147-158. DOI:10.3997/1873-0604.2009004 Kucukdemirci,M., Piro.S.,Baydemir,N.,Ozer.,E. Zamuner.,D. 2015. Mathematical and Statistical Integration approach on archaeological prospection data,case studies from Aizanoi-Turkey. 43rd Computer Applications and Quantitative Methods in Archaeology, Siena. Kvamme,K.,2007. Integrating Multiple Geophysical Datasets, Remote Sensing in archaeology, Springer,Boston. Piro,S.,Mauriello.,P. and Cammarano.,F.2000. Quantitative Integration of Geophysical methods for Archaeological Prospection. Archaeological prospection 7(4): 203-213. Piro S., Papale E., Zamuner D., 2016. Different integrated geophysical approaches to investigate archaeological sites in urban and suburban area. Geophysical Research Abstracts Vol. 18, EGU2016.

Sequential geophysical and flow inversion to characterize fracture networks in subsurface systems

DOE PAGES

Mudunuru, Maruti Kumar; Karra, Satish; Makedonska, Nataliia; ...

2017-09-05

Subsurface applications, including geothermal, geological carbon sequestration, and oil and gas, typically involve maximizing either the extraction of energy or the storage of fluids. Fractures form the main pathways for flow in these systems, and locating these fractures is critical for predicting flow. However, fracture characterization is a highly uncertain process, and data from multiple sources, such as flow and geophysical are needed to reduce this uncertainty. We present a nonintrusive, sequential inversion framework for integrating data from geophysical and flow sources to constrain fracture networks in the subsurface. In this framework, we first estimate bounds on the statistics formore » the fracture orientations using microseismic data. These bounds are estimated through a combination of a focal mechanism (physics-based approach) and clustering analysis (statistical approach) of seismic data. Then, the fracture lengths are constrained using flow data. In conclusion, the efficacy of this inversion is demonstrated through a representative example.« less

High-resolution geophysical data from the sea floor surrounding the Western Elizabeth Islands, Massachusetts

USGS Publications Warehouse

Pendleton, Elizabeth A.; Twichell, David C.; Foster, David S.; Worley, Charles R.; Irwin, Barry J.; Danforth, William W.

2011-01-01

Geophysical and geospatial data were collected in the nearshore area surrounding the western Elizabeth Islands, Massachusetts on the U.S. Geological Survey research vessel Rafael during September 2010 in a collaborative effort between the U.S. Geological Survey and the Massachusetts, Office of Coastal Zone Management. This report describes the results of the short-term goals of this collaborative effort, which were to map the geology of the inner shelf zone of the western Elizabeth Islands and study the geologic processes that have contributed to its evolution. Data collected during the survey include: Bathymetric and sidescan-sonar data, chirp seismic-reflection data , sound velocity profiles, and navigation data. The long-term goals of this project are to provide high-resolution geophysical data that will support research on the influence of sea-level change and sediment supply on coastal evolution and inventory subtidal marine habitat type and distribution within the coastal zone of Massachusetts.

Sequential geophysical and flow inversion to characterize fracture networks in subsurface systems

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

Mudunuru, Maruti Kumar; Karra, Satish; Makedonska, Nataliia

Subsurface applications, including geothermal, geological carbon sequestration, and oil and gas, typically involve maximizing either the extraction of energy or the storage of fluids. Fractures form the main pathways for flow in these systems, and locating these fractures is critical for predicting flow. However, fracture characterization is a highly uncertain process, and data from multiple sources, such as flow and geophysical are needed to reduce this uncertainty. We present a nonintrusive, sequential inversion framework for integrating data from geophysical and flow sources to constrain fracture networks in the subsurface. In this framework, we first estimate bounds on the statistics formore » the fracture orientations using microseismic data. These bounds are estimated through a combination of a focal mechanism (physics-based approach) and clustering analysis (statistical approach) of seismic data. Then, the fracture lengths are constrained using flow data. In conclusion, the efficacy of this inversion is demonstrated through a representative example.« less

Application of time-variable process noise in terrestrial reference frames determined from VLBI data

NASA Astrophysics Data System (ADS)

Soja, Benedikt; Gross, Richard S.; Abbondanza, Claudio; Chin, Toshio M.; Heflin, Michael B.; Parker, Jay W.; Wu, Xiaoping; Balidakis, Kyriakos; Nilsson, Tobias; Glaser, Susanne; Karbon, Maria; Heinkelmann, Robert; Schuh, Harald

2018-05-01

In recent years, Kalman filtering has emerged as a suitable technique to determine terrestrial reference frames (TRFs), a prime example being JTRF2014. The time series approach allows variations of station coordinates that are neither reduced by observational corrections nor considered in the functional model to be taken into account. These variations are primarily due to non-tidal geophysical loading effects that are not reduced according to the current IERS Conventions (2010). It is standard practice that the process noise models applied in Kalman filter TRF solutions are derived from time series of loading displacements and account for station dependent differences. So far, it has been assumed that the parameters of these process noise models are constant over time. However, due to the presence of seasonal and irregular variations, this assumption does not truly reflect reality. In this study, we derive a station coordinate process noise model allowing for such temporal variations. This process noise model and one that is a parameterized version of the former are applied in the computation of TRF solutions based on very long baseline interferometry data. In comparison with a solution based on a constant process noise model, we find that the station coordinates are affected at the millimeter level.

Understanding coupling between natural and human systems to ensure disease resilient societies

NASA Astrophysics Data System (ADS)

Jutla, A.; Nguyen, T. H.; Colwell, R. R.; Akanda, A. S.

2016-12-01

Human well-being is one of the key long-term indicators of a sustainable environment. John Snow, a prominent 19th century physician, provided insights on the role of drinking contaminated water and cholera outbreak(s). Extrapolation of Snow's discovery on locating source of cholera bacteria (in local wells) lead to the tenets of traditional doctrines of environmental sustainability of water where source capacities (such as physical condition of water) are directly linked to sink capacities (e.g., bacterial growth in water) of a system, a balance that must be maintained to sustain human life supporting mechanisms. With a changing climate, stress on availability of safe drinking water is likely to increase, particularly where population vulnerability intersects with hydroclimatic extremes. This raises a critical question on how environmental sustainability of water will affect human societies. A dynamic equilibrium exists between large scale geophysical (e.g., sea surface temperature-SST; precipitation, evaporative fluxes) and local scale water-ecological processes (salinity, plankton, organic matter) in water resources (ponds, rivers, lakes). The ecological processes aid in growth and proliferation of water based pathogens (such as cholera, Rotavirus, Shigella and other vibrios). Societal determinants, such as access to safe drinking water and sanitation facilities, defines interaction of human population with water. The feedback loop, between geophysical and water-ecological processes is fundamental to ensure a sustainable environment for human well-being. However, the feedback loops are often misconstrued resulting in massive loss of human life, and further leading to outbreak of diseases at various spatial and temporal scales across region(s). Using historical data on Cholera and Zika virus as examples, we will demonstrate the intricacies involved in understanding coupled human-natural system. The two infections result from a very different asymmetric hydroclimatic regimens, and the feedback loops determine interaction of humans with the pathogens.

A Neural-Network-Based Semi-Automated Geospatial Classification Tool

NASA Astrophysics Data System (ADS)

Hale, R. G.; Herzfeld, U. C.

2014-12-01

North America's largest glacier system, the Bering Bagley Glacier System (BBGS) in Alaska, surged in 2011-2013, as shown by rapid mass transfer, elevation change, and heavy crevassing. Little is known about the physics controlling surge glaciers' semi-cyclic patterns; therefore, it is crucial to collect and analyze as much data as possible so that predictive models can be made. In addition, physical signs frozen in ice in the form of crevasses may help serve as a warning for future surges. The BBGS surge provided an opportunity to develop an automated classification tool for crevasse classification based on imagery collected from small aircraft. The classification allows one to link image classification to geophysical processes associated with ice deformation. The tool uses an approach that employs geostatistical functions and a feed-forward perceptron with error back-propagation. The connectionist-geostatistical approach uses directional experimental (discrete) variograms to parameterize images into a form that the Neural Network (NN) can recognize. In an application to preform analysis on airborne video graphic data from the surge of the BBGS, an NN was able to distinguish 18 different crevasse classes with 95 percent or higher accuracy, for over 3,000 images. Recognizing that each surge wave results in different crevasse types and that environmental conditions affect the appearance in imagery, we designed the tool's semi-automated pre-training algorithm to be adaptable. The tool can be optimized to specific settings and variables of image analysis: (airborne and satellite imagery, different camera types, observation altitude, number and types of classes, and resolution). The generalization of the classification tool brings three important advantages: (1) multiple types of problems in geophysics can be studied, (2) the training process is sufficiently formalized to allow non-experts in neural nets to perform the training process, and (3) the time required to manually pre-sort imagery into classes is greatly reduced.

Processing AIRS Scientific Data Through Level 2

NASA Technical Reports Server (NTRS)

Oliphant, Robert; Lee, Sung-Yung; Chahine, Moustafa; Susskind, Joel; arnet, Christopher; McMillin, Larry; Goldberg, Mitchell; Blaisdell, John; Rosenkranz, Philip; Strow, Larrabee

2007-01-01

The Atmospheric Infrared Spectrometer (AIRS) Science Processing System (SPS) is a collection of computer programs, denoted product generation executives (PGEs), for processing the readings of the AIRS suite of infrared and microwave instruments orbiting the Earth aboard NASA s Aqua spacecraft. AIRS SPS at an earlier stage of development was described in "Initial Processing of Infrared Spectral Data' (NPO-35243), NASA Tech Briefs, Vol. 28, No. 11 (November 2004), page 39. To recapitulate: Starting from level 0 (representing raw AIRS data), the PGEs and their data products are denoted by alphanumeric labels (1A, 1B, and 2) that signify the successive stages of processing. The cited prior article described processing through level 1B (the level-2 PGEs were not yet operational). The level-2 PGEs, which are now operational, receive packages of level-1B geolocated radiance data products and produce such geolocated geophysical atmospheric data products such as temperature and humidity profiles. The process of computing these geophysical data products is denoted "retrieval" and is quite complex. The main steps of the process are denoted microwave-only retrieval, cloud detection and cloud clearing, regression, full retrieval, and rapid transmittance algorithm.

Innovation of floating time domain electromagnetic method in the case of environmental geophysics

NASA Astrophysics Data System (ADS)

Nurjanah, Siti; Widodo

2017-07-01

Geophysics has some methods that can be used to reveal the subsurface structure of the earth. The physical features obtained from the acquisition then analyzed and interpreted, so that it can be a great lead to interpret the physical contents, determine its position and its distribution. Geophysical methods also can be used to help the environment contamination survey which is referred to environmental geophysics. There are many sources of pollution that can harm the nature, for example, the source in the form of solid waste, liquid waste containing heavy metals, or radioactive, and etc. As time passes, these sources might settle in any sedimentary area and become sediments. Time Domain Electromagnetic (TDEM) is a trustworthy method to detect the presence of conductive anomaly due to sediment accumulation. Innovation of floating TDEM created to maximize the potential of the method, so that it can be used in aquatic environments. The configuration of TDEM modified using pipes and tires during the process of measurements. We conducted numerical simulation using Marquardt and Occam Algorithms towards synthetic model to ensure the capability of the proposed design. The development of this innovation is expected to be very useful to repair the natural conditions, especially in the water.

Thomas J. Ahrens (1936-2010)

NASA Astrophysics Data System (ADS)

Jeanloz, Raymond

2011-03-01

Thomas J. Ahrens, a leader in the study of high-pressure shock wave and planetary impact phenomena, died at his home in Pasadena, Calif., on 24 November 2010 at the age of 74. He was the California Institute of Technology's Fletcher Jones Professor of Geophysics, emeritus since 2005 but professionally active to the end. He had been president of AGU's Tectonophysics section, editor of Journal of Geophysical Research, founding member of both the Mineral and Rock Physics and Study of the Earth's Deep Interior focus groups, and editor—more like key driving force—for AGU's Handbook of Physical Constants. Tom was a pioneer in experimental and numerical studies of the effects of projectiles hitting a target at velocities exceeding the speed of sound (hypervelocity impact), arguably the most important geophysical process in the formation, growth, and, in many cases, surface evolution of planets. As a professor at Caltech, he established the foremost university laboratory for shock wave experiments, where students and research associates from around the world pursued basic research in geophysics, planetary science, and other disciplines. Previously, high-pressure shock experiments were conducted primarily in national laboratories, where they were initially associated with the development of nuclear weapons.

Separation of atmospheric, oceanic and hydrological polar motion excitation mechanisms based on a combination of geometric and gravimetric space observations

NASA Astrophysics Data System (ADS)

Göttl, F.; Schmidt, M.; Seitz, F.; Bloßfeld, M.

2015-04-01

The goal of our study is to determine accurate time series of geophysical Earth rotation excitations to learn more about global dynamic processes in the Earth system. For this purpose, we developed an adjustment model which allows to combine precise observations from space geodetic observation systems, such as Satellite Laser Ranging (SLR), Global Navigation Satellite Systems, Very Long Baseline Interferometry, Doppler Orbit determination and Radiopositioning Integrated on Satellite, satellite altimetry and satellite gravimetry in order to separate geophysical excitation mechanisms of Earth rotation. Three polar motion time series are applied to derive the polar motion excitation functions (integral effect). Furthermore we use five time variable gravity field solutions from Gravity Recovery and Climate Experiment to determine not only the integral mass effect but also the oceanic and hydrological mass effects by applying suitable filter techniques and a land-ocean mask. For comparison the integral mass effect is also derived from degree 2 potential coefficients that are estimated from SLR observations. The oceanic mass effect is also determined from sea level anomalies observed by satellite altimetry by reducing the steric sea level anomalies derived from temperature and salinity fields of the oceans. Due to the combination of all geodetic estimated excitations the weaknesses of the individual processing strategies can be reduced and the technique-specific strengths can be accounted for. The formal errors of the adjusted geodetic solutions are smaller than the RMS differences of the geophysical model solutions. The improved excitation time series can be used to improve the geophysical modeling.

The concept of geothermal exploration in west Java based on geophysical data

NASA Astrophysics Data System (ADS)

Gaffar, Eddy Z.

2018-02-01

Indonesia has the largest geothermal prospects in the world and most of them are concentrated in Java and Sumatera. The ones on Sumatra island are generally controlled by Sumatra Fault, either the main fault or the second and the third order fault. Geothermal in Java is still influenced by the subduction of oceanic plates from the south of Java island that forms the southern mountains extending from West Java to East Java. From a geophysical point of view, there is still no clue or concept that accelerates the process of geothermal exploration. The concept is that geothermal is located around the volcano (referred to the volcano as a host) and around the fault (fault as a host). There is another method from remote sensing analysis that often shows circular feature. In a study conducted by LIPI, we proposed a new concept for geothermal exploration which is from gravity analysis using Bouguer anomaly data from Java Island, which also show circular feature. The feature is supposed to be an "ancient crater" or a hidden caldera. Therefore, with this hypothesis, LIPI Geophysics team will try to prove whether this symptom can help accelerate the process of geothermal exploration on the island of West Java. Geophysical methods might simplify the exploration of geothermal prospect in West Java. Around the small circular feature, there are some large geothermal prospect areas such as Guntur, Kamojang, Drajat, Papandayan, Karaha Bodas, Patuha. The concept proposed by our team will try be applied to explore geothermal in Java Island for future work.

Improved Products for Assimilation and Model Validation from the Atmospheric Infrared Sounder (AIRS) on Aqua

NASA Technical Reports Server (NTRS)

Pagano, Thomas S.

2008-01-01

The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7-15.4 micrometer spectral region with spectral resolution of better than 1200. Key channels from the AIRS Level 1B calibrated radiance product are currently assimilated into operational weather forecasts at NCEP and other international agencies. Additional Level 2 products for assimilation include the AIRS cloud cleared radiances and the geophysical retrieved temperature and water vapor profiles. The AIRS products are also used to validate climate model vertical and horizontal biases and transport of water vapor and key trace gases including Carbon Dioxide and Ozone. The wide variety of products available from the AIRS make it well suited to study processes affecting the interaction of these products.

Note: "Lock-in accelerometry" to follow sink dynamics in shaken granular matter.

PubMed

Sánchez-Colina, G; Alonso-Llanes, L; Martínez, E; Batista-Leyva, A J; Clement, C; Fliedner, C; Toussaint, R; Altshuler, E

2014-12-01

Understanding the penetration dynamics of intruders in granular beds is relevant not only for fundamental physics, but also for geophysical processes and construction on sediments or granular soils in areas potentially affected by earthquakes. While the penetration of intruders in two dimensional (2D) laboratory granular beds can be followed using video recording, this is useless in three dimensional (3D) beds of non-transparent materials such as common sand. Here, we propose a method to quantify the sink dynamics of an intruder into laterally shaken granular beds based on the temporal correlations between the signals from a reference accelerometer fixed to the shaken granular bed, and a probe accelerometer deployed inside the intruder. Due to its analogy with the working principle of a lock-in amplifier, we call this technique lock-in accelerometry.

Efficient Flowline Simulations of Ice Shelf-Ocean Interactions: Sensitivity Studies with a Fully Coupled Model

NASA Technical Reports Server (NTRS)

Walker, Ryan Thomas; Holland, David; Parizek, Byron R.; Alley, Richard B.; Nowicki, Sophie M. J.; Jenkins, Adrian

2013-01-01

Thermodynamic flowline and plume models for the ice shelf-ocean system simplify the ice and ocean dynamics sufficiently to allow extensive exploration of parameters affecting ice-sheet stability while including key physical processes. Comparison between geophysically and laboratory-based treatments of ice-ocean interface thermodynamics shows reasonable agreement between calculated melt rates, except where steep basal slopes and relatively high ocean temperatures are present. Results are especially sensitive to the poorly known drag coefficient, highlighting the need for additional field experiments to constrain its value. These experiments also suggest that if the ice-ocean interface near the grounding line is steeper than some threshold, further steepening of the slope may drive higher entrainment that limits buoyancy, slowing the plume and reducing melting; if confirmed, this will provide a stabilizing feedback on ice sheets under some circumstances.

Crump Geyser Exploration and Drilling Project. High Precision Geophysics and Detailed Structural Exploration and Slim Well Drilling

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

Fairbank, Brian D.; Smith, Nicole

The Crump Geyser Exploration and Drilling Project – High Precision Geophysics and Detailed Structural Exploration and Slim Well Drilling ran from January 29, 2010 to September 30, 2013. During Phase 1 of the project, collection of all geophysical surveys was completed as outlined in the Statement of Project Objectives. In addition, a 5000-foot full sized exploration well was drilled by Ormat, and preexisting drilling data was discovered for multiple temperature gradient wells within the project area. Three dimensional modeling and interpretation of results from the geophysical surveys and drilling data gave confidence to move to the project into Phase 2more » drilling. Geological and geophysical survey interpretations combined with existing downhole temperature data provided an ideal target for the first slim-hole drilled as the first task in Phase 2. Slim-hole 35-34 was drilled in September 2011 and tested temperature, lithology, and permeability along the primary range-bounding fault zone near its intersection with buried northwest-trending faults that have been identified using geophysical methods. Following analysis of the results of the first slim-hole 35-34, the second slim hole was not drilled and subsequent project tasks, including flowing differential self-potential (FDSP) surveys that were designed to detail the affect of production and injection on water flow in the shallow aquifer, were not completed. NGP sold the Crump project to Ormat in August 2014, afterwards, there was insufficient time and interest from Ormat available to complete the project objectives. NGP was unable to continue managing the award for a project they did not own due to liability issues and Novation of the award was not a viable option due to federal award timelines. NGP submitted a request to mutually terminate the award on February 18, 2015. The results of all of the technical surveys and drilling are included in this report. Fault interpretations from surface geology, aeromag, seismic, and gravity data sets are in good agreement, illustrating two or more major range-bounding faults and buried northwest trending faults. The intersections of these fault systems provide the primary targets for drilling.« less

Publications - GPR 2015-4 | Alaska Division of Geological & Geophysical

Science.gov Websites

Geologic Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey airborne geophysical survey data compilation Authors: Burns, L.E., Geoterrex-Dighem, Stevens Exploration airborne geophysical survey data compilation: Alaska Division of Geological & Geophysical Surveys

Publications - GPR 2015-3 | Alaska Division of Geological & Geophysical

Science.gov Websites

Geologic Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey electromagnetic and magnetic airborne geophysical survey data compilation Authors: Burns, L.E., Fugro Airborne magnetic airborne geophysical survey data compilation: Alaska Division of Geological & Geophysical

The University of Texas Institute for Geophysics Marine Geology and Geophysics Field Course

NASA Astrophysics Data System (ADS)

Davis, M. B.; Gulick, S. P.; Allison, M. A.; Goff, J. A.; Duncan, D. D.; Saustrup, S.

2011-12-01

The University of Texas Institute for Geophysics, part of the Jackson School of Geosciences, annually offers an intensive three-week marine geology and geophysics field course during the spring-summer intersession. Now in year five, the course provides hands-on instruction and training for graduate and upper-level undergraduate students in data acquisition, processing, interpretation, and visualization. Techniques covered include high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, several types of sediment coring, grab sampling, and the sedimentology of resulting seabed samples (e.g., core description, grain size analysis, x-radiography, etc.). Students seek to understand coastal and sedimentary processes of the Gulf Coast and continental shelf through application of these techniques in an exploratory mode. Students participate in an initial three days of classroom instruction designed to communicate geological context of the field area (which changes each year) along with theoretical and technical background on each field method. The class then travels to the Gulf Coast for a week of at-sea field work. In the field, students rotate between two small research vessels: one vessel, the 22' aluminum-hulled R/V Lake Itasca, owned and operated by UTIG, is used principally for multibeam bathymetry, sidescan sonar, and sediment sampling; the other, NOAA's R/V Manta or the R/V Acadiana, operated by the Louisiana Universities Marine Consortium, is used primarily for high-resolution seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, gravity coring, and vibracoring. While at sea, students assist with survey design, learn instrumentation set up, acquisition parameters, data quality control, and safe instrument deployment and retrieval. In teams of three, students work in onshore field labs preparing sediment samples for particle size analysis and initial data processing. During the course's final week, teams return to the classroom where they integrate, interpret, and visualize data in a final project using industry-standard software such as Focus, Landmark, Caris, and Fledermaus. The course concludes with a series of professional-level final presentations and discussions in which students examine geologic history and/or sedimentary processes represented by the Gulf Coast continental shelf. With course completion, students report a greater understanding of marine geology and geophysics via the course's intensive, hands-on, team approach and low instructor to student ratio. This course satisfies field experience requirements for some degree programs and thus provides a unique alternative to land-based field courses.

What Should We Be Teaching about the Atmosphere?

ERIC Educational Resources Information Center

Atkinson, Bruce

1978-01-01

Because study of climatology in most college and university geography departments is descriptive, it gives no fundamental insights into geophysical processes. In order to achieve a quantified understanding of atmospheric processes, geographers must have expertise in mathematics, physics, and instrumentation. For journal availability, see 506 593.…

An Integrated Modeling Framework Forecasting Ecosystem Exposure— A Systems Approach to the Cumulative Impacts of Multiple Stressors

EPA Science Inventory

Freshwater habitats provide fishable, swimmable and drinkable resources and are a nexus of geophysical and biological processes. These processes in turn influence the persistence and sustainability of populations, communities and ecosystems. Climate change and landuse change enco...

Error characterization of microwave satellite soil moisture data sets using fourier analysis

USDA-ARS?s Scientific Manuscript database

Soil moisture is a key geophysical variable in hydrological and meteorological processes. Accurate and current observations of soil moisture over meso to global scales used as inputs to hydrological, weather and climate modelling will benefit the predictability and understanding of these processes. ...

78 FR 57354 - Takes of Marine Mammals Incidental to Specified Activities; Low-Energy Marine Geophysical Survey...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-18

... September 6 through November 12, 2013. ADDRESSES: A copy of the final IHA and application are available by... reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or... and NMFS's responses: Comment 1: The Commission recommends that NMFS require SIO, through the...

Improved estimation of hydraulic conductivity by combining stochastically simulated hydrofacies with geophysical data

PubMed Central

Zhu, Lin; Gong, Huili; Chen, Yun; Li, Xiaojuan; Chang, Xiang; Cui, Yijiao

2016-01-01

Hydraulic conductivity is a major parameter affecting the output accuracy of groundwater flow and transport models. The most commonly used semi-empirical formula for estimating conductivity is Kozeny-Carman equation. However, this method alone does not work well with heterogeneous strata. Two important parameters, grain size and porosity, often show spatial variations at different scales. This study proposes a method for estimating conductivity distributions by combining a stochastic hydrofacies model with geophysical methods. The Markov chain model with transition probability matrix was adopted to re-construct structures of hydrofacies for deriving spatial deposit information. The geophysical and hydro-chemical data were used to estimate the porosity distribution through the Archie’s law. Results show that the stochastic simulated hydrofacies model reflects the sedimentary features with an average model accuracy of 78% in comparison with borehole log data in the Chaobai alluvial fan. The estimated conductivity is reasonable and of the same order of magnitude of the outcomes of the pumping tests. The conductivity distribution is consistent with the sedimentary distributions. This study provides more reliable spatial distributions of the hydraulic parameters for further numerical modeling. PMID:26927886

Non-linear processes in the Earth atmosphere boundary layer

NASA Astrophysics Data System (ADS)

Grunskaya, Lubov; Valery, Isakevich; Dmitry, Rubay

2013-04-01

The work is connected with studying electromagnetic fields in the resonator Earth-Ionosphere. There is studied the interconnection of tide processes of geophysical and astrophysical origin with the Earth electromagnetic fields. On account of non-linear property of the resonator Earth-Ionosphere the tides (moon and astrophysical tides) in the electromagnetic Earth fields are kinds of polyharmonic nature. It is impossible to detect such non-linear processes with the help of the classical spectral analysis. Therefore to extract tide processes in the electromagnetic fields, the method of covariance matrix eigen vectors is used. Experimental investigations of electromagnetic fields in the atmosphere boundary layer are done at the distance spaced stations, situated on Vladimir State University test ground, at Main Geophysical Observatory (St. Petersburg), on Kamchatka pen., on Lake Baikal. In 2012 there was continued to operate the multichannel synchronic monitoring system of electrical and geomagnetic fields at the spaced apart stations: VSU physical experimental proving ground; the station of the Institute of Solar and Terrestrial Physics of Russian Academy of Science (RAS) at Lake Baikal; the station of the Institute of volcanology and seismology of RAS in Paratunka; the station in Obninsk on the base of the scientific and production society "Typhoon". Such investigations turned out to be possible after developing the method of scanning experimental signal of electromagnetic field into non- correlated components. There was used a method of the analysis of the eigen vectors ofthe time series covariance matrix for exposing influence of the moon tides on Ez. The method allows to distribute an experimental signal into non-correlated periodicities. The present method is effective just in the situation when energetical deposit because of possible influence of moon tides upon the electromagnetic fields is little. There have been developed and realized in program components in the form of PAS instruments of processes of geophysical and man-triggered nature; to predict the presence of the features of geophysical nature in the electromagnetic field of the atmosphere boundary surface layer; to study dynamics the analyzed signals coming from the geophysical and man-triggered sources in the electrical and magnetic fields of the atmosphere boundary surface layer; to expose changes of the investigated time series in the periods preceding the appearance of the predicted phenomena; to form clusters of the time series being the features of the predicted events. On the base of the exposed clusters of the time series there have been built the predicting rules allowing to coordinate the probability of appearing the groups of the occurred events. The work is carried out with supporting of Program FPP #14.B37.210668, FPP #5.2071.2011, RFBR #11-05-97518.

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

Vinick, Charles; Riccobono, Antonino, MS; Messing, Charles G., Ph.D.

Dehlsen Associates, LLC was awarded a grant by the United States Department of Energy (DOE) Golden Field Office for a project titled 'Siting Study Framework and Survey Methodology for Marine and Hydrokinetic Energy Project in Offshore Southeast Florida,' corresponding to DOE Grant Award Number DE-EE0002655 resulting from DOE funding Opportunity Announcement Number DE-FOA-0000069 for Topic Area 2, and it is referred to herein as 'the project.' The purpose of the project was to enhance the certainty of the survey requirements and regulatory review processes for the purpose of reducing the time, efforts, and costs associated with initial siting efforts ofmore » marine and hydrokinetic energy conversion facilities that may be proposed in the Atlantic Ocean offshore Southeast Florida. To secure early input from agencies, protocols were developed for collecting baseline geophysical information and benthic habitat data that can be used by project developers and regulators to make decisions early in the process of determining project location (i.e., the siting process) that avoid or minimize adverse impacts to sensitive marine benthic habitat. It is presumed that such an approach will help facilitate the licensing process for hydrokinetic and other ocean renewable energy projects within the study area and will assist in clarifying the baseline environmental data requirements described in the U.S. Department of the Interior Bureau of Ocean Energy Management, Regulation and Enforcement (formerly Minerals Management Service) final regulations on offshore renewable energy (30 Code of Federal Regulations 285, published April 29, 2009). Because projects generally seek to avoid or minimize impacts to sensitive marine habitats, it was not the intent of this project to investigate areas that did not appear suitable for the siting of ocean renewable energy projects. Rather, a two-tiered approach was designed with the first step consisting of gaining overall insight about seabed conditions offshore southeastern Florida by conducting a geophysical survey of pre-selected areas with subsequent post-processing and expert data interpretation by geophysicists and experienced marine biologists knowledgeable about the general project area. The second step sought to validate the benthic habitat types interpreted from the geophysical data by conducting benthic video and photographic field surveys of selected habitat types. The goal of this step was to determine the degree of correlation between the habitat types interpreted from the geophysical data and what actually exists on the seafloor based on the benthic video survey logs. This step included spot-checking selected habitat types rather than comprehensive evaluation of the entire area covered by the geophysical survey. It is important to note that non-invasive survey methods were used as part of this study and no devices of any kind were either temporarily or permanently attached to the seabed as part of the work conducted under this project.« less

Relationship between deep structure and oil-gas in the eastern Tarim Basin

NASA Astrophysics Data System (ADS)

Yu, Changqing; Qu, Chen; Han, Jianguang

2017-04-01

The Tarim Basin is a large composite superimposed basin which developed in the Presinian continental basement. It is an important area for oil and gas replacement in China. In the eastern part of Tarim Basin, the exploration and research degree is very low and less system, especially in the study of tectonic evolution and physical property change. Basing on the study of geophysics, drilling and regional geological data in this area, analysis of comprehensive geophysical, geological and geophysical analysis comparison are lunched by new methods and new technology of geophysical exploration. Fault, tectonic evolution and change of deep character in the eastern Tarim Basin are analyzed in system. Through in-depth study and understanding of the deep structure and physical changes of the eastern region, we obtain the fault characteristics in the study area and the deep structure and physical change maps to better guide the oil and gas exploration in this area. The east area is located in the eastern Tarim Basin, west from the Garr Man depression, Well Kunan 1 - Well Gucheng 4 line to the East, north to Kuruketage uplift group near Qunke 1 wells, south to Cherchen fault zone, east to Lop Nor depression, an area of about 9 * 104 square kilometres, Including the East of Garr Man sag, Yingjisu depression, Kongquehe slope, Tadong low uplift and the Lop Nor uplift, five two grade tectonic units. The east area of Tarim is belonging to Tarim plate. It changes with the evolution of the Tarim plate. The Tarim plate is closely related to the collision between the Yining - the Junggar plate, the Siberia plate and the southern Qiangtang - the central Kunlun plate. Therefore, it creates a complex tectonic pattern in the eastern Tarim basin. Earth electromagnetic, gravity, deep seismic and other geophysical data are processed by a new generation of geophysical information theory and method, including multi-scale inversion of potential field inversion (Hou and Yang, 2011), 3D magnetotelluric data (Yang et al., 2012) and micro seismic wave field information recognition technology in the eastern Tarim Basin. Combining the information of the deep faults, tectonic evolution characteristics of the study area and the physical changes from geological data, we analyze the relationship between the change of the physical structure and the oil and gas, and predict the favorable oil and gas area and the exploration target area by information extraction, processing and interpretation analysis based on integrated geophysical technology. References 1. Hou, Z. Z., W. C. Yang, 2011, multi scale gravity field inversion and density structure in Tarim Basin: Chinese science, 41, 29-39. 2. Yang W. C., J. L. Wang, H. Z. Zhong, 2012, The main port of the Tarim Basin Analysis of magnetic field and magnetic source structure: Chinese Journal of Geophysics, 55, 1278-1287.

Environmental Geophysics

EPA Pesticide Factsheets

The Environmental Geophysics website features geophysical methods, terms and references; forward and inverse geophysical models for download; and a decision support tool to guide geophysical method selection for a variety of environmental applications.

Statistical Algorithms for Designing Geophysical Surveys to Detect UXO Target Areas

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

O'Brien, Robert F.; Carlson, Deborah K.; Gilbert, Richard O.

2005-07-29

The U.S. Department of Defense is in the process of assessing and remediating closed, transferred, and transferring military training ranges across the United States. Many of these sites have areas that are known to contain unexploded ordnance (UXO). Other sites or portions of sites are not expected to contain UXO, but some verification of this expectation using geophysical surveys is needed. Many sites are so large that it is often impractical and/or cost prohibitive to perform surveys over 100% of the site. In that case, it is particularly important to be explicit about the performance required of the survey. Thismore » article presents the statistical algorithms developed to support the design of geophysical surveys along transects (swaths) to find target areas (TAs) of anomalous geophysical readings that may indicate the presence of UXO. The algorithms described here determine 1) the spacing between transects that should be used for the surveys to achieve a specified probability of traversing the TA, 2) the probability of both traversing and detecting a TA of anomalous geophysical readings when the spatial density of anomalies within the TA is either uniform (unchanging over space) or has a bivariate normal distribution, and 3) the probability that a TA exists when it was not found by surveying along transects. These algorithms have been implemented in the Visual Sample Plan (VSP) software to develop cost-effective transect survey designs that meet performance objectives.« less

Statistical Algorithms for Designing Geophysical Surveys to Detect UXO Target Areas

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

O'Brien, Robert F.; Carlson, Deborah K.; Gilbert, Richard O.

2005-07-28

The U.S. Department of Defense is in the process of assessing and remediating closed, transferred, and transferring military training ranges across the United States. Many of these sites have areas that are known to contain unexploded ordnance (UXO). Other sites or portions of sites are not expected to contain UXO, but some verification of this expectation using geophysical surveys is needed. Many sites are so large that it is often impractical and/or cost prohibitive to perform surveys over 100% of the site. In such cases, it is particularly important to be explicit about the performance required of the surveys. Thismore » article presents the statistical algorithms developed to support the design of geophysical surveys along transects (swaths) to find target areas (TAs) of anomalous geophysical readings that may indicate the presence of UXO. The algorithms described here determine (1) the spacing between transects that should be used for the surveys to achieve a specified probability of traversing the TA, (2) the probability of both traversing and detecting a TA of anomalous geophysical readings when the spatial density of anomalies within the TA is either uniform (unchanging over space) or has a bivariate normal distribution, and (3) the probability that a TA exists when it was not found by surveying along transects. These algorithms have been implemented in the Visual Sample Plan (VSP) software to develop cost-effective transect survey designs that meet performance objectives.« less

Geophysical insights on the GIA process provided by high-quality constraints from peripheral regions: An outlook on perspectives from North America and from the Mediterranean basin

NASA Astrophysics Data System (ADS)

Roy, K.; Peltier, W. R.

2017-12-01

Our understanding of the Earth-Ice-Ocean interactions that have accompanied the large glaciation-deglaciation process characteristic of the last half of the Pleistocene has benefited significantly from the development of high-quality models of the Glacial Isostatic Adjustment (GIA) process. These models provide fundamental insight on the large changes in sea level and land ice cover over this time period, as well as key constraints on the viscosity structure of the Earth's interior. Their development has benefited from the recent availability of high-quality constraints from regions of forebulge collapse. In particular, over North America, the joint use of high-quality sea level data from the U.S. East coast, together with the vast network of precise space-geodetic observations of crustal motion existing over most of the interior of the continent, has led to the latest ICE-7G_NA (VM7) model (Roy & Peltier, GJI, 2017). In this paper, exciting opportunities provided by such high-quality observations related to the GIA process will be discussed, not only in the context of the continuing effort to refine global models of this phenomenon, but also in terms of the fundamental insight they may provide on outstanding issues in high-pressure geophysics, paleoclimatology or hydrogeology. Specific examples where such high-quality observations can be used (either separately, or using a combination of independent sources) will be presented, focusing particularly on constraints from the North American continent and from the Mediterranean basin. This work will demonstrate that, given the high-quality of currently available constraints on the GIA process, considerable further geophysical insight can be obtained based upon the use of spherically-symmetric models of the viscosity structure of the planet.

Interactive Geophysical Mapping on the Web

NASA Astrophysics Data System (ADS)

Meertens, C.; Hamburger, M.; Estey, L.; Weingroff, M.; Deardorff, R.; Holt, W.

2002-12-01

We have developed a set of interactive, web-based map utilities that make geophysical results accessible to a large number and variety of users. These tools provide access to pre-determined map regions via a simple Html/JavaScript interface or to user-selectable areas using a Java interface to a Generic Mapping Tools (GMT) engine. Users can access a variety of maps, satellite images, and geophysical data at a range of spatial scales for the earth and other planets of the solar system. Developed initially by UNAVCO for study of global-scale geodynamic processes, users can choose from a variety of base maps (satellite mosaics, global topography, geoid, sea-floor age, strain rate and seismic hazard maps, and others) and can then add a number of geographic and geophysical overlays for example coastlines, political boundaries, rivers and lakes, NEIC earthquake and volcano locations, stress axes, and observed and model plate motion and deformation velocity vectors representing a compilation of 2933 geodetic measurements from around the world. The software design is flexible allowing for construction of special editions for different target audiences. Custom maps been implemented for UNAVCO as the "Jules Verne Voyager" and "Voyager Junior", for the International Lithosphere Project's "Global Strain Rate Map", and for EarthScope Education and Outreach as "EarthScope Voyager Jr.". For the later, a number of EarthScope-specific features have been added, including locations of proposed USArray (seismic), Plate Boundary Observatory (geodetic), and San Andreas Fault Observatory at Depth sites plus detailed maps and geographically referenced examples of EarthScope-related scientific investigations. In addition, we are developing a website that incorporates background materials and curricular activities that encourage users to explore Earth processes. A cluster of map processing computers and nearly a terabyte of disk storage has been assembled to power the generation of interactive maps and provide space for a very large collection of map data. A portal to these map tools can be found at: http://jules.unavco.ucar.edu.

Staff - Linda D. Natrop | Alaska Division of Geological & Geophysical

Science.gov Websites

DGGS library, timesheet processing, state credit card accounting, public information desk, mail and postage, vehicle coordinator, property records, maintain supplies, and other administrative duties as

Editorial: Reviewer Selection Process and New Areas of Expertise in GEMS

NASA Technical Reports Server (NTRS)

Liemohn, Michael W.; Balikhin, Michael; Kepko, Larry; Rodger, Alan; Wang, Yuming

2016-01-01

One method of selecting potential reviewers for papers submitted to the Journal of Geophysical Research Space Physics is to filter the user database within the Geophysical Electronic Manuscript System (GEMS) by areas of expertise. The list of these areas in GEMS can be self selected by users in their profile settings. The Editors have added 18 new entries to this list, an increase of 33 more than the previous 55 entries. All space physicists are strongly encouraged to update their profile settings in GEMS, especially their areas of expertise selections, and details of how to do this are provided.

Gravity data of Nevada

USGS Publications Warehouse

Ponce, David A.

1997-01-01

Gravity data for the entire state of Nevada and adjacent parts of California, Utah, and Arizona are available on this CD-ROM. About 80,000 gravity stations were compiled primarily from the National Geophysical Data Center and the U.S. Geological Survey. Gravity data was reduced to the Geodetic Reference System of 1967 and adjusted to the Gravity Standardization Net 1971 gravity datum. Data were processed to complete Bouguer and isostatic gravity anomalies by applying standard gravity corrections including terrain and isostatic corrections. Selected principal fact references and a list of sources for data from the National Geophysical Data Center are included.

Editorial: Reviewer selection process and new areas of expertise in GEMS

NASA Astrophysics Data System (ADS)

Liemohn, Michael W.; Balikhin, Michael; Kepko, Larry; Rodger, Alan; Wang, Yuming

2016-06-01

One method of selecting potential reviewers for papers submitted to the Journal of Geophysical Research Space Physics is to filter the user database within the Geophysical Electronic Manuscript System (GEMS) by areas of expertise. The list of these areas in GEMS can be self selected by users in their profile settings. The Editors have added 18 new entries to this list, an increase of 33% more than the previous 55 entries. All space physicists are strongly encouraged to update their profile settings in GEMS, especially their areas of expertise selections, and details of how to do this are provided.

Localized Smart-Interpretation

NASA Astrophysics Data System (ADS)

Lundh Gulbrandsen, Mats; Mejer Hansen, Thomas; Bach, Torben; Pallesen, Tom

2014-05-01

The complex task of setting up a geological model consists not only of combining available geological information into a conceptual plausible model, but also requires consistency with availably data, e.g. geophysical data. However, in many cases the direct geological information, e.g borehole samples, are very sparse, so in order to create a geological model, the geologist needs to rely on the geophysical data. The problem is however, that the amount of geophysical data in many cases are so vast that it is practically impossible to integrate all of them in the manual interpretation process. This means that a lot of the information available from the geophysical surveys are unexploited, which is a problem, due to the fact that the resulting geological model does not fulfill its full potential and hence are less trustworthy. We suggest an approach to geological modeling that 1. allow all geophysical data to be considered when building the geological model 2. is fast 3. allow quantification of geological modeling. The method is constructed to build a statistical model, f(d,m), describing the relation between what the geologists interpret, d, and what the geologist knows, m. The para- meter m reflects any available information that can be quantified, such as geophysical data, the result of a geophysical inversion, elevation maps, etc... The parameter d reflects an actual interpretation, such as for example the depth to the base of a ground water reservoir. First we infer a statistical model f(d,m), by examining sets of actual interpretations made by a geological expert, [d1, d2, ...], and the information used to perform the interpretation; [m1, m2, ...]. This makes it possible to quantify how the geological expert performs interpolation through f(d,m). As the geological expert proceeds interpreting, the number of interpreted datapoints from which the statistical model is inferred increases, and therefore the accuracy of the statistical model increases. When a model f(d,m) successfully has been inferred, we are able to simulate how the geological expert would perform an interpretation given some external information m, through f(d|m). We will demonstrate this method applied on geological interpretation and densely sampled airborne electromagnetic data. In short, our goal is to build a statistical model describing how a geological expert performs geological interpretation given some geophysical data. We then wish to use this statistical model to perform semi automatic interpretation, everywhere where such geophysical data exist, in a manner consistent with the choices made by a geological expert. Benefits of such a statistical model are that 1. it provides a quantification of how a geological expert performs interpretation based on available diverse data 2. all available geophysical information can be used 3. it allows much faster interpretation of large data sets.

Immersive, hands-on, team-based geophysical education at the University of Texas Marine Geology and Geophysics Field Course

NASA Astrophysics Data System (ADS)

Saustrup, S.; Gulick, S. P.; Goff, J. A.; Davis, M. B.; Duncan, D.; Reece, R.

2013-12-01

The University of Texas Institute for Geophysics (UTIG), part of the Jackson School of Geosciences, annually offers a unique and intensive three-week marine geology and geophysics field course during the spring/summer semester intersession. Now entering its seventh year, the course transitions students from a classroom environment through real-world, hands-on field acquisition, on to team-oriented data interpretation, culminating in a professional presentation before academic and industry employer representatives. The course is available to graduate students and select upper-division undergraduates, preparing them for direct entry into the geoscience workforce or for further academic study. Geophysical techniques used include high-resolution multichannel seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, sediment coring, grab sampling, data processing, and laboratory analysis of sediments. Industry-standard equipment, methods, software packages, and visualization techniques are used throughout the course, putting students ahead of many of their peers in this respect. The course begins with a 3-day classroom introduction to the field area geology, geophysical methods, and computing resources used. The class then travels to the Gulf Coast for a week of hands-on field and lab work aboard two research vessels: UTIG's 22-foot, aluminum hulled Lake Itasca; and NOAA's 82-foot high-speed catamaran R/V Manta. The smaller vessel handles primarily shallow, inshore targets using multibeam bathymetry, sidescan sonar, and grab sampling. The larger vessel is used both inshore and offshore for multichannel seismic, CHIRP profiling, multibeam bathymetry, gravity coring, and vibracoring. Field areas to date have included Galveston and Port Aransas, Texas, and Grand Isle, Louisiana, with further work in Grand Isle scheduled for 2014. In the field, students work in teams of three, participating in survey design, instrument set-up, field deployment, data acquisition optimization, quality control, data archival, log-keeping, real-time data processing, laboratory sediment analysis, and even boat-handling. Teams are rotated through the two vessels and the onshore field laboratory to ensure that each student has hands-on experience with each aspect of the process. Although all students work on all data areas in the field, after returning from the field each team is assigned a particular region or geologic problem to interpret. Each team prepares and presents a formal presentation to UTIG researchers and industry representatives, explaining and defending their interpretations. This unique approach to hands-on field training, real-world science, and project-based teamwork helps prepare students for direct entry into the workforce, giving them a leg up on competitors for positions. This course has an impressive success ratio to show, with many students receiving job offers directly as a result of their participation in the course.

Process for guidance, containment, treatment, and imaging in a subsurface environment utilizing ferro-fluids

DOEpatents

Moridis, George J.; Oldenburg, Curtis M.

2001-01-01

Disclosed are processes for monitoring and control of underground contamination, which involve the application of ferrofluids. Two broad uses of ferrofluids are described: (1) to control liquid movement by the application of strong external magnetic fields; and (2) to image liquids by standard geophysical methods.

Geophysical characterization of saltwater intrusion in a coastal aquifer: The case of Martil-Alila plain (North Morocco)

NASA Astrophysics Data System (ADS)

Himi, Mahjoub; Tapias, Josefiina; Benabdelouahab, Sara; Salhi, Adil; Rivero, Luis; Elgettafi, Mohamed; El Mandour, Abdenabi; Stitou, Jamal; Casas, Albert

2017-02-01

Several factors can affect the quantity and the quality of groundwater resources, but in coastal aquifers seawater intrusion is often the most significant issue regarding freshwater supply. Further, saltwater intrusion is a worldwide issue because about seventy percent of the world's population lives in coastal regions. Generally, fresh groundwater not affected by saltwater intrusion is characterized by low salinity and therefore low electrical conductivity (EC) values. Consequently, high values of EC in groundwater along the coastline are usually associated to seawater intrusion. This effect is amplified if the coastal aquifer is overexploited with a subsequent gradual displacement of the freshwater-saltwater interface towards the continent. Delineation of marine intrusion in coastal aquifers has traditionally relied upon observation wells and collection of water samples. This approach may miss important hydrologic features related to saltwater intrusion in areas where access is difficult and where wells are widely spaced. Consequently, the scarcity of sampling points and sometimes their total absence makes the number of data available limited and most of the time not representative for mapping the spatial and temporal variability of groundwater salinity. In this study, we use a series of geophysical methods for characterizing the aquifer geometry and the extension of saltwater intrusion in the Martil-Alila coastal region (Morocco) as a complement to geological and hydrogeochemical data. For this reason, we carried out three geophysical surveys: Gravity, Electrical Resistivity and Frequency Domain Electromagnetic. The geometry of the basin has been determined from the interpretation of a detailed gravity survey. Electrical resistivity models derived from vertical electrical soundings allowed to characterize the vertical and the lateral extensions of aquifer formations. Finally, frequency domain electromagnetic methods allowed delineating the extension of the saltwater intrusion.

Present Status of Geophysics Departments at Universities in Turkey from Perspectives of their Students

NASA Astrophysics Data System (ADS)

Karabulut, Savas; Baris Aygordu, Ozan; Benli, Aral

2015-04-01

This survey was conducted in order to make the students who are having geophysical engineering education in Turkey evaluate their departments from their own perspectives.By doing this we aimed to make a contribution to the geophysical engineering education and we tried to find out if there were any deficiencies in that matter and also the possible solutions.In this respect aproximately 500 undergraduates from 11 different state universities were asked 25 questions regarding both their socio-economic status and their ideas on their future professions.In the survey the students were asked to state their high-school graduation;whether it is an Anatolian High-school,Vocational high-school or college and if geophysical engineering education was their first choice at the university entrance exams.The students' foreign language status-if there were any- except their mother tongue were asked and also their opinions on geophysical education at their universities.Besides these the students were asked in which fields they study in their department; Seismology, Geophysics or Applied Geophysics and if they found the geophysical equipments adequate in their departments and also the programming languages-like data processing laboratories.In the survey we tried to find out if the students were encouraged to participate in the meetings and congresses in their field by their instructers and if they found the theoretical training adequate besides the practical one.Above all the students answered questions if they had any worries about future job opportunities ; what their goals were after they graduate and if they could easily get access to any kind of Turkish sources in their field and if they were reluctant to work at any jobs part-time or full-time during university.The results of the survey were presented to the Union of Turkish Engineers and Architects and also to the related heads of departments.The most striking parts of this survey were that the students were not edequate enough to interpret and analyse the foreign articles and journeys because of their poor foreign language levels and % 80,5 were very anxious to get a proper job in the future and %78,6 did not find the sources edequate in Turkish and %91,8 of these students thought that theoratical training was not enough besides practical one.

Integration of GIS, Electromagnetic and Electrical Methods in the Delimitation of Groundwater Polluted by Effluent Discharge (Salamanca, Spain): A Case Study.

PubMed

Montes, Rubén Vidal; Martínez-Graña, Antonio Miguel; Martínez Catalán, José Ramón; Arribas, Puy Ayarza; Sánchez San Román, Francisco Javier; Zazo, Caridad

2017-11-10

The present work envisages the possible geometry of a contaminated plume of groundwater near hospital facilities by combining GIS (Geographic Information System) and geophysical methods. The rock underlying the soil and thin sedimentary cover of the study area is moderately fractured quartzite, which makes aquifers vulnerable to pollution. The GIS methodology is used to calculate the area that would be affected by the effluent source of residual water, based on algorithms that consider ground surface mapping (slopes, orientations, accumulated costs and cost per distance). Geophysical methods (electromagnetic induction and electric resistivity tomography) use changes in the electrical conductivity or resistivity of the subsurface to determine the geometry of the discharge and the degree of contamination. The model presented would allow a preliminary investigation regarding potential corrective measures.

Integration of GIS, Electromagnetic and Electrical Methods in the Delimitation of Groundwater Polluted by Effluent Discharge (Salamanca, Spain): A Case Study

PubMed Central

Montes, Rubén Vidal; Sánchez San Román, Francisco Javier; Zazo, Caridad

2017-01-01

The present work envisages the possible geometry of a contaminated plume of groundwater near hospital facilities by combining GIS (Geographic Information System) and geophysical methods. The rock underlying the soil and thin sedimentary cover of the study area is moderately fractured quartzite, which makes aquifers vulnerable to pollution. The GIS methodology is used to calculate the area that would be affected by the effluent source of residual water, based on algorithms that consider ground surface mapping (slopes, orientations, accumulated costs and cost per distance). Geophysical methods (electromagnetic induction and electric resistivity tomography) use changes in the electrical conductivity or resistivity of the subsurface to determine the geometry of the discharge and the degree of contamination. The model presented would allow a preliminary investigation regarding potential corrective measures. PMID:29125556

Electrical Resistivity Tomography and Ground Penetrating Radar for locating buried petrified wood sites: a case study in the natural monument of the Petrified Forest of Evros, Greece

NASA Astrophysics Data System (ADS)

Vargemezis, George; Diamanti, Nectaria; Tsourlos, Panagiotis; Fikos, Ilias

2014-05-01

A geophysical survey was carried out in the Petrified Forest of Evros, the northernmost regional unit of Greece. This collection of petrified wood has an age of approximately 35 million years and it is the oldest in Greece (i.e., older than the well-known Petrified Forest of Lesvos island located in the North Aegean Sea and which is possibly the largest of the petrified forests worldwide). Protection, development and maintenance projects still need to be carried out at the area despite all fears regarding the forest's fate since many petrified logs remain exposed both in weather conditions - leading to erosion - and to the public. This survey was conducted as part of a more extensive framework regarding the development and protection of this natural monument. Geophysical surveying has been chosen as a non-destructive investigation method since the area of application is both a natural ecosystem and part of cultural heritage. Along with electrical resistivity tomography (ERT), ground penetrating radar (GPR) surveys have been carried out for investigating possible locations of buried fossilized tree trunks. The geoelectrical sections derived from ERT data in combination with the GPR profiles provided a broad view of the subsurface. Two and three dimensional subsurface geophysical images of the surveyed area have been constructed, pointing out probable locations of petrified logs. Regarding ERT, petrified trunks have been detected as high resistive bodies, while lower resistivity values were more related to the surrounding geological materials. GPR surveying has also indicated buried petrified log locations. As these two geophysical methods are affected in different ways by the subsurface conditions, the combined use of both techniques enhanced our ability to produce more reliable interpretations of the subsurface. After the completion of the geophysical investigations of this first stage, petrified trunks were revealed after a subsequent excavation at indicated locations. Moreover, we identified possible buried petrified targets at locations yet to be excavated.

Hydrogeological characterisation of a glacially affected barrier island - the North Frisian Island of Föhr

NASA Astrophysics Data System (ADS)

Burschil, T.; Scheer, W.; Kirsch, R.; Wiederhold, H.

2012-04-01

We present the application of geophysical investigations to characterise and improve the geological/hydrogeological model through the estimation of petrophysical parameters for groundwater modelling. Seismic reflection and airborne electromagnetic surveys in combination with borehole information enhance the 3-D geological model and allow a petrophysical interpretation of the subsurface. The North Sea Island of Föhr has a very complex underground structure what was already known from boreholes. The local waterworks use a freshwater body embedded in saline groundwater. Several glaciations disordered the Youngest Tertiary and Quaternary sediments by glaciotectonic thrust-faulting as well as incision and refill of glacial valleys. Both underground structures have a strong impact on the distribution of freshwater bearing aquifers. An initial hydrogeological model of Föhr was built from borehole data alone and was restricted to the southern part of the island where in the sandy areas of the Geest a large freshwater body was formed. We improved the geological/hydrogeological model by adding data from different geophysical methods, e.g. airborne electromagnetics (EM) for mapping the resistivity of the entire island, seismic reflections for detailed cross sections in the groundwater catchment area, and geophysical borehole logging for calibration of these measurements. An integrated evaluation of the results from the different geophysical methods yields reliable data. To determinate petrophysical parameter about 18 borehole logs, more than 75 m deep, and nearby airborne EM inversion models were analyzed concerning resistivity. We establish an empirical relation between measured resistivity and hydraulic conductivity for the specific area - the North Sea island of Föhr. Five boreholes concerning seismic interval velocities discriminate sand and till. The interpretation of these data was the basis for building the geological/hydrogeological 3-D model. We fitted the relevant model layers to all geophysical and geological data and created a consistent 3-D model. This model is the fundament for groundwater simulations considering forecasted changes in precipitation and sea level rise due to climate change.

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.

GPR Diagnostics of columns in archaeological contexts

NASA Astrophysics Data System (ADS)

Soldovieri, Francesco; Masini, Nicola; Persico, Raffaele; Catapano, Ilaria

2017-04-01

In the last decade the use of Ground Penetrating radar (GPR) applied to cultural heritage has been strongly increasing thanks to both technological development of sensors and softwares for data processing and cultural reasons such as the increasing awareness of conservators and archaeologist of the benefits of this method in terms of reduction of costs and time and risk associated with restoration works. This made GPR a mature technique for investigating different types of works of art and building elements of historical interest, including masonry structures, frescoes, mosaics [1-3], in the context of scientific projects, decision support activities aimed at the diagnosis of decay pathologies, and educational activities. One of the most complex building elements to be investigated by GPR are the columns both for the geometry of the object and for the several expected features to be detected including fractures, dishomogeneities and metallic connection elements. The work deals with the Ground Penetrating Radar diagnostic surveys at the prestigious archaeological site of Pompei. In particular, GPR surveys were carried out in two different areas, Palestra Grande and Tempio di Giove. The first campaign was carried out also as educational activity of the "International School "GEOPHYSICS AND REMOTE SENSING FOR ARCHAEOLOGY". The School aimed at giving the opportunity to scholars, PhD students, researchers and specialists in Geophysics, Remote Sensing and Archaeology to deepen their knowledge and expertise with geophysical and remote sensing techniques for archaeology and cultural heritage documentation and management. This survey was carried on two kinds of columns, with circular and rectangular section in order to detect possible hidden defects affecting their integrity. The second survey was carried out at Tempio di Giove, on request of the Soprintendenza Pompei, in order to gain information about the presence of reinforcement structures, which may be put inside the columns during a previous work carried out about thirty years ago and whose memory documentation was lost. Both the GPR surveys were carried out by using the K2-RIS IDS system equipped with a high frequency antenna, working at the central frequency of 2GHz. Moreover, the imaging results have been obtained by processing the raw data by means of the end-user friendly software interface designed at the Institute for Electromagnetic Sensing of the Environment - National Research Council of Italy. This interface was some years ago to make possible a simple management of 2D and 3D microwave tomographic approaches based on the Born approximation [4-6].The GPR surveys have confirmed the presence of metallic elements inside few of the investigated columns. [1] Masini N., Nuzzo L., Rizzo E. 2007, GPR investigations for the study and the restoration of the Rose Window of Troia Cathedral (Southern Italy), Near Surface Geophysics, 5 (5), pp. 287-300, doi: 10.3997/1873-0604.2007010 [2] Leucci G., Masini N., Persico R., Soldovieri F. 2011. GPR and sonic tomography for structural restoration: the case of the cathedral of Tricarico, Journal of Geophysics and Engineering, 8 (3), 76-92, doi: 10.1088/1742-2132/8/3/S08 [3] Masini N., Persico R., Rizzo E., Calia A., Giannotta M.T., Quarta G., Pagliuca A. 2010, Integrated Techniques for Analysis and Monitoring of Historical Monuments: the case of S.Giovanni al Sepolcro in Brindisi (Southern Italy), Near Surface Geophysics, 8(5), 423-432, doi:10.3997/1873-0604.2010012 [4] F. Soldovieri, J. Hugenschmidt, R. Persico, G. Leone, A linear inverse scattering algorithm for realistic GPR applications. Near Surf. Geophys. 5(1), 29-42 (2007) [5] I. Catapano, A. Affinito, G. Gennarelli, F.di Maio, A. Loperte, F. Soldovieri, "Full three-dimensional imaging via ground penetrating radar: assessment in controlled conditions and on field for archaeological prospecting", Appl. Phys. A, 2013 [6] I. Catapano, A. Affinito, F. Soldovieri, A user friendly interface for microwave tomography enhanced GPR surveys", EGU General Assembly 2013, vol. 15.

Publications - RI 2000-1B | Alaska Division of Geological & Geophysical

Science.gov Websites

; Formations; Fossils; Geologic; Geologic Map; Geology; Glacial Processes; Kemik Sandstone; Marine; Marine ; Tectonics; Tertiary; Trace Fossils; Turbidites; Volcanic Ash Top of Page Department of Natural Resources

Permit application and approval chronology for a small airgun survey offshore southern California, June 1999

USGS Publications Warehouse

Childs, Jonathan R.; Normark, William R.; Fisher, Michael A.

1999-01-01

Offshore geophysical surveys are subject to increased restrictions resulting from new or revised Federal legislation and increased authority of State agencies that deal with environmental issues. This report reviews the process followed by the U.S. Geological Survey to obtain necessary approvals for a marine geophysical survey conducted in June, 1999, offshore Southern California. Discussions and negotiations between the USGS, National Marine Fisheries Service, the California Coastal Commission, the California State Lands Commission, and various other interested parties during six months prior to the survey are documented. A suggested timeframe that should be followed for obtaining the approvals and permits for future work offshore California is based on the outcome of the permitting process for the 1999 cruise, as well as continuing dialog with representatives of the Federal and State entities involved.

The Virtual Geophysics Laboratory (VGL): Scientific Workflows Operating Across Organizations and Across Infrastructures

NASA Astrophysics Data System (ADS)

Cox, S. J.; Wyborn, L. A.; Fraser, R.; Rankine, T.; Woodcock, R.; Vote, J.; Evans, B.

2012-12-01

The Virtual Geophysics Laboratory (VGL) is web portal that provides geoscientists with an integrated online environment that: seamlessly accesses geophysical and geoscience data services from the AuScope national geoscience information infrastructure; loosely couples these data to a variety of gesocience software tools; and provides large scale processing facilities via cloud computing. VGL is a collaboration between CSIRO, Geoscience Australia, National Computational Infrastructure, Monash University, Australian National University and the University of Queensland. The VGL provides a distributed system whereby a user can enter an online virtual laboratory to seamlessly connect to OGC web services for geoscience data. The data is supplied in open standards formats using international standards like GeoSciML. A VGL user uses a web mapping interface to discover and filter the data sources using spatial and attribute filters to define a subset. Once the data is selected the user is not required to download the data. VGL collates the service query information for later in the processing workflow where it will be staged directly to the computing facilities. The combination of deferring data download and access to Cloud computing enables VGL users to access their data at higher resolutions and to undertake larger scale inversions, more complex models and simulations than their own local computing facilities might allow. Inside the Virtual Geophysics Laboratory, the user has access to a library of existing models, complete with exemplar workflows for specific scientific problems based on those models. For example, the user can load a geological model published by Geoscience Australia, apply a basic deformation workflow provided by a CSIRO scientist, and have it run in a scientific code from Monash. Finally the user can publish these results to share with a colleague or cite in a paper. This opens new opportunities for access and collaboration as all the resources (models, code, data, processing) are shared in the one virtual laboratory. VGL provides end users with access to an intuitive, user-centered interface that leverages cloud storage and cloud and cluster processing from both the research communities and commercial suppliers (e.g. Amazon). As the underlying data and information services are agnostic of the scientific domain, they can support many other data types. This fundamental characteristic results in a highly reusable virtual laboratory infrastructure that could also be used for example natural hazards, satellite processing, soil geochemistry, climate modeling, agriculture crop modeling.

Geomorphological and geophysical investigations for the characterization of the Roman Carsulae site (Tiber basin, Central Italy)

NASA Astrophysics Data System (ADS)

Bottari, C.; Aringoli, D.; Carluccio, R.; Castellano, C.; D'Ajello Caracciolo, F.; Gasperini, M.; Materazzi, M.; Nicolosi, I.; Pambianchi, G.; Pieruccini, P.; Sepe, V.; Urbini, S.; Varazi, F.

2017-08-01

This paper aims to bring to light the possible linkage between karstic phenomena and the human occupation of the Roman site of Carsulae (Tiber basin, Central Italy). Dolines are a typical morphological expression of karst rocks' dissolution and collapse and, usually, they represent a potential hazard for human activities and, in particular, in the care and maintenance of cultural heritage sites. In this study, we observed that the development of a subsidence doline caused severe damage to some archaeological structures at the Carsulae monumental site. According to the results obtained in our investigation, three sites at least with karst dissolution phenomena in the shallow calcareous tufa layer have been identified. One of them subsided probably in Roman times and produced a sharp deformation of the decumanus. In order to understand the evolution of this territory an integrated geomorphological and geophysical survey was carried out. The combination between the information derived from different geophysical techniques, such as: Electrical Resistivity Tomography (ERT), Frequency-Domain Electromagnetism (FDEM), and Ground Penetrating Radar (GPR) clearly pointed out that the calcareous tufa layer is characterized by an irregular geometry and this resulted in the investigated area being affected by karst dissolution in several parts. Four boreholes opportunely located, provided direct information about the depth and the alteration of the calcareous tufa basement and precious calibration data for the geophysical methods. This study contributes to improving our knowledge on the evolution of the Carsulae archaeological site providing a new insight into the adaptation of ancient human societies in this problematic territory.

SIGKit: Software for Introductory Geophysics Toolkit

NASA Astrophysics Data System (ADS)

Kruse, S.; Bank, C. G.; Esmaeili, S.; Jazayeri, S.; Liu, S.; Stoikopoulos, N.

2017-12-01

The Software for Introductory Geophysics Toolkit (SIGKit) affords students the opportunity to create model data and perform simple processing of field data for various geophysical methods. SIGkit provides a graphical user interface built with the MATLAB programming language, but can run even without a MATLAB installation. At this time SIGkit allows students to pick first arrivals and match a two-layer model to seismic refraction data; grid total-field magnetic data, extract a profile, and compare this to a synthetic profile; and perform simple processing steps (subtraction of a mean trace, hyperbola fit) to ground-penetrating radar data. We also have preliminary tools for gravity, resistivity, and EM data representation and analysis. SIGkit is being built by students for students, and the intent of the toolkit is to provide an intuitive interface for simple data analysis and understanding of the methods, and act as an entrance to more sophisticated software. The toolkit has been used in introductory courses as well as field courses. First reactions from students are positive. Think-aloud observations of students using the toolkit have helped identify problems and helped shape it. We are planning to compare the learning outcomes of students who have used the toolkit in a field course to students in a previous course to test its effectiveness.

An overview on integrated data system for archiving and sharing marine geology and geophysical data in Korea Institute of Ocean Science & Technology (KIOST)

NASA Astrophysics Data System (ADS)

Choi, Sang-Hwa; Kim, Sung Dae; Park, Hyuk Min; Lee, SeungHa

2016-04-01

We established and have operated an integrated data system for managing, archiving and sharing marine geology and geophysical data around Korea produced from various research projects and programs in Korea Institute of Ocean Science & Technology (KIOST). First of all, to keep the consistency of data system with continuous data updates, we set up standard operating procedures (SOPs) for data archiving, data processing and converting, data quality controls, and data uploading, DB maintenance, etc. Database of this system comprises two databases, ARCHIVE DB and GIS DB for the purpose of this data system. ARCHIVE DB stores archived data as an original forms and formats from data providers for data archive and GIS DB manages all other compilation, processed and reproduction data and information for data services and GIS application services. Relational data management system, Oracle 11g, adopted for DBMS and open source GIS techniques applied for GIS services such as OpenLayers for user interface, GeoServer for application server, PostGIS and PostgreSQL for GIS database. For the sake of convenient use of geophysical data in a SEG Y format, a viewer program was developed and embedded in this system. Users can search data through GIS user interface and save the results as a report.

Chirp subbottom profile data collected in 2015 from the northern Chandeleur Islands, Louisiana

USGS Publications Warehouse

Forde, Arnell S.; DeWitt, Nancy T.; Fredericks, Jake J.; Miselis, Jennifer L.

2018-01-30

As part of the Barrier Island Evolution Research project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted a nearshore geophysical survey around the northern Chandeleur Islands, Louisiana, in September 2015. The objective of the project is to improve the understanding of barrier island geomorphic evolution, particularly storm-related depositional and erosional processes that shape the islands over annual to interannual time scales (1–5 years). Collecting geophysical data can help researchers identify relations between the geologic history of the islands and their present day morphology and sediment distribution. High-resolution geophysical data collected along this rapidly changing barrier island system can provide a unique time-series dataset to further the analyses and geomorphological interpretations of this and other coastal systems, improving our understanding of coastal response and evolution over medium-term time scales (months to years). Subbottom profile data were collected in September 2015 offshore of the northern Chandeleur Islands, during USGS Field Activity Number 2015-331-FA. Data products, including raw digital chirp subbottom data, processed subbottom profile images, survey trackline map, navigation files, geographic information system data files and formal Federal Geographic Data Committee metadata, and Field Activity Collection System and operation logs are available for download.

Automated recognition of stratigraphic marker shales from geophysical logs in iron ore deposits

NASA Astrophysics Data System (ADS)

Silversides, Katherine; Melkumyan, Arman; Wyman, Derek; Hatherly, Peter

2015-04-01

The mining of stratiform ore deposits requires a means of determining the location of stratigraphic boundaries. A variety of geophysical logs may provide the required data but, in the case of banded iron formation hosted iron ore deposits in the Hamersley Ranges of Western Australia, only one geophysical log type (natural gamma) is collected for this purpose. The information from these logs is currently processed by slow manual interpretation. In this paper we present an alternative method of automatically identifying recurring stratigraphic markers in natural gamma logs from multiple drill holes. Our approach is demonstrated using natural gamma geophysical logs that contain features corresponding to the presence of stratigraphically important marker shales. The host stratigraphic sequence is highly consistent throughout the Hamersley and the marker shales can therefore be used to identify the stratigraphic location of the banded iron formation (BIF) or BIF hosted ore. The marker shales are identified using Gaussian Processes (GP) trained by either manual or active learning methods and the results are compared to the existing geological interpretation. The manual method involves the user selecting the signatures for improving the library, whereas the active learning method uses the measure of uncertainty provided by the GP to select specific examples for the user to consider for addition. The results demonstrate that both GP methods can identify a feature, but the active learning approach has several benefits over the manual method. These benefits include greater accuracy in the identified signatures, faster library building, and an objective approach for selecting signatures that includes the full range of signatures across a deposit in the library. When using the active learning method, it was found that the current manual interpretation could be replaced in 78.4% of the holes with an accuracy of 95.7%.

Geophysical Investigation of a Thermokarst Lake Talik in Continuous Permafrost

NASA Astrophysics Data System (ADS)

Creighton, A.; Parsekian, A.; Arp, C. D.; Jones, B. M.; Babcock, E.; Bondurant, A. C.

2016-12-01

On the Arctic Coastal Plain (ACP) of northern Alaska, shallow thermokarst lakes cover up to 25% of the landscape. These lakes occupy depressions created by the subsidence of thawed, ice-rich permafrost. Areas of unfrozen sediment, or taliks, can form under lakes that have a mean annual bottom temperature greater than 0°C. The geometry of these taliks, as well as the processes that create them, are important for understanding interactions between surface water, groundwater, and carbon cycling. Non-invasive geophysical methods are a useful means to study talik sediments as borehole studies yield few data points, and the contrast between unfrozen and frozen sediments is an ideal geophysical target. To study talik configuration associated with an actively expanding thermokarst lake, we conducted a geophysical transect across Peatball Lake. This lake has an estimated initiation age of 1400 calendar years BP. Over the past 60 years, lake surface area has increased through thermal and mechanical shoreline erosion. A talik of previously unknown thickness likely exists below Peatball Lake. We conducted a transect of transient electromagnetic soundings across the lake extending into the surrounding terrestrial environment. Since permafrost has relatively high resistivity compared to talik sediments, the interpreted electrical structure of the subsurface likely reflects talik geometry. We also conducted nuclear magnetic resonance soundings at representative locations along the transect. These measurements can provide data on sub-lake sediment properties including water content. Together, these measurements resolve the talik structure across the lake transect and showed evidence of varying talik thicknesses from the lake edge to center. These is no evidence of a talik at the terrestrial control sites. These results can help constrain talik development models and thus provide insight into Arctic and permafrost processes in the face of a changing climate.

A survey of natural aggregate properties and characteristics important in remote sensing and airborne geophysics

USGS Publications Warehouse

Knepper, D.H.; Langer, W.H.; Miller, S.

1995-01-01

Natural aggregate is vital to the construction industry. Although natural aggregate is a high volume/low value commodity that is abundant, new sources are becoming increasingly difficult to find and develop because of rigid industry specifications, political considerations, development and transportation costs, and environmental concerns. There are two primary sources of natural aggregate: (1) exposed or near-surface bedrock that can be crushed, and (2) deposits of sand and gravel. Remote sensing and airborne geophysics detect surface and near-surface phenomena, and may be useful for detecting and mapping potential aggregate sources; however, before a methodology for applying these techniques can be developed, it is necessary to understand the type, distribution, physical properties, and characteristics of natural aggregate deposits. The distribution of potential aggregate sources is closely tied to local geologic history. Conventional exploration for natural aggregate deposits has been largely a ground-based operation, although aerial photographs and topographic maps have been extensively used to target possible deposits. Today, the exploration process also considers factors such as the availability of the land, space and water supply for processing, political and environmental factors, and distance from the market; exploration and planning cannot be separated. There are many physical properties and characteristics by which to judge aggregate material for specific applications; most of these properties and characteristics pertain only to individual aggregate particles. The application of remote sensing and airborne geophysical measurements to detecting and mapping potential aggregate sources, however, is based on intrinsic bulk physical properties and extrinsic characteristics of the deposits that can be directly measured, mathematically derived from measurement, or interpreted with remote sensing and geophysical data. ?? 1995 Oxford UniversityPress.

Near real-time imaging of molasses injections using time-lapse electrical geophysics at the Brandywine DRMO, Brandywine, Maryland

NASA Astrophysics Data System (ADS)

Versteeg, R. J.; Johnson, T.; Major, B.; Day-Lewis, F. D.; Lane, J. W.

2010-12-01

Enhanced bioremediation, which involves introduction of amendments to promote biodegradation, increasingly is used to accelerate cleanup of recalcitrant compounds and has been identified as the preferred remedial treatment at many contaminated sites. Although blind introduction of amendments can lead to sub-optimal or ineffective remediation, the distribution of amendment throughout the treatment zone is difficult to measure using conventional sampling. Because amendments and their degradation products commonly have electrical properties that differ from those of ambient soil, time-lapse electrical geophysical monitoring has the potential to verify amendment emplacement and distribution. In order for geophysical monitoring to be useful, however, results of the injection ideally should be accessible in near real time. In August 2010, we demonstrated the feasibility of near real-time, autonomous electrical geophysical monitoring of amendment injections at the former Defense Reutilization and Marketing Office (DRMO) in Brandywine, Maryland. Two injections of about 1000 gallons each of molasses, a widely used amendment for enhanced bioremediation, were monitored using measurements taken with borehole and surface electrodes. During the injections, multi-channel resistance data were recorded; data were transmitted to a server and processed using a parallel resistivity inversion code; and results in the form of time-lapse imagery subsequently were posted to a website. This process occurred automatically without human intervention. The resulting time-lapse imagery clearly showed the evolution of the molasses plume. The delay between measurements and online delivery of images was between 45 and 60 minutes, thus providing actionable information that could support decisions about field procedures and a check on whether amendment reached target zones. This experiment demonstrates the feasibility of using electrical imaging as a monitoring tool both during amendment emplacement and post-injection to track amendment distribution, geochemical breakdown, and other remedial effects.

Surface-geophysical techniques used to detect existing and infilled scour holes near bridge piers

USGS Publications Warehouse

Placzek, Gary; Haeni, F.P.

1995-01-01

Surface-geophysical techniques were used with a position-recording system to study riverbed scour near bridge piers. From May 1989 to May 1993. Fathometers, fixed- and swept-frequency con- tinuous seismic-reflection profiling (CSP) systems, and a ground-penetrating radar (GPR) system were used with a laser-positioning system to measure the depth and extent of existing and infilled scour holes near bridge piers. Equipment was purchased commercially and modified when necessary to interface the components and (or) to improve their performance. Three 200-kHz black-and-white chart- recording Fathometers produced profiles of the riverbed that included existing scour holes and exposed pier footings. The Fathometers were used in conjunction with other geophysical techniques to help interpret the geophysical data. A 20-kHz color Fathometer delineated scour-hole geometry and, in some cases, the thickness of fill material in the hole. The signal provided subbottom information as deep as 10 ft in fine-grained materials and resolved layers of fill material as thin as 1 foot thick. Fixed-frequency and swept-frequency CSP systems were evaluated. The fixed-frequency system used a 3.5-, 7.0-, or 14-kHz signal. The 3.5-kHz signal pene- trated up to 50 ft of fine-grained material and resolved layers as thin as 2.5-ft thick. The 14-kHz signal penetrated up to 20 ft of fine-grained material and resolved layers as thin as 1-ft thick. The swept-frequency systems used a signal that swept from 2- to 16-kHz. With this system, up to 50 ft of penetration was achieved, and fill material as thin as 1 ft was resolved. Scour-hole geometry, exposed pier footings, and fill thickness in scour holes were detected with both CSP systems. The GPR system used an 80-, 100-, or 300-megahertz signal. The technique produced records in water up to 15 ft deep that had a specific conductance less than 200x11ms/cm. The 100-MHz signal penetrated up to 40 ft of resistive granular material and resolved layers as thin as 2-ft thick. Scour-hole geometry, the thickness of fill material in scour holes, and riverbed deposition were detected using this technique. Processing techniques were applied after data collection to assist with the interpretation of the data. Data were transferred from the color Fathometer, CSP, and GPR systems to a personal computer, and a commercially available software package designed to process GPR data was used to process the GPR and CSP data. Digital filtering, predictive-deconvolution, and migration algorithms were applied to some of the data. The processed data were displayed and printed as color amplitude or wiggle-trace plots. These processing methods eased and improved the interpretation of some of the data, but some interference from side echoes from bridge piers and multiple reflections remained in the data. The surface-geophysical techniques were applied at six bridge sites in Connecticut. Each site had different water depths, specific conductance, and riverbed materials. Existing and infilled scour holes, exposed pier footings, and riverbed deposition were detected by the surveys. The interpretations of the geophysical data were confirmed by comparing the data with lithologic and (or) probing data.

An application of the geophysical methods and ALS DTM for the identification of the geological structure in the Kraśnik region - Lublin Upland, Poland

NASA Astrophysics Data System (ADS)

Kamiński, Mirosław

2017-11-01

The purpose of the study was the assessment of the viability of selected geophysical methods and the Airborne Laser Scanning (ALS) for the identification and interpretation of the geological structure. The studied area is covered with a dense forest. For this reason, the ALS numerical terrain model was applied for the analysis of the topography. Three geophysical methods were used: gravimetric, in the form of a semi-detailed gravimetric photograph, Vertical Electrical Sounding (VES), and Electrical Resistivity Tomography (ERT). The numerical terrain model enabled the identification of Jurassic limestone outcrops and interpretation of the directions of the faults network. The geological interpretation of the digitally processed gravimetric data enabled the determination of the spatial orientation of the synclines and anticlines axes and of the course directions of main faults. Vertical Electrical Sounding carried along the section line perpendicular to the Gościeradów anticline axis enabled the interpretation of the lithology of this structure and identification of its complex tectonic structure. The shallow geophysical surveys using the ERT method enabled the estimation of the thickness of Quaternary formations deposited unconformably on the highly eroded Jurassic limestone outcrop. The lithology of Quaternary, Cretaceous and Jurassic rocks was also interpreted.

An Uncertainty Quantification Framework for Remote Sensing Retrievals

NASA Astrophysics Data System (ADS)

Braverman, A. J.; Hobbs, J.

2017-12-01

Remote sensing data sets produced by NASA and other space agencies are the result of complex algorithms that infer geophysical state from observed radiances using retrieval algorithms. The processing must keep up with the downlinked data flow, and this necessitates computational compromises that affect the accuracies of retrieved estimates. The algorithms are also limited by imperfect knowledge of physics and of ancillary inputs that are required. All of this contributes to uncertainties that are generally not rigorously quantified by stepping outside the assumptions that underlie the retrieval methodology. In this talk we discuss a practical framework for uncertainty quantification that can be applied to a variety of remote sensing retrieval algorithms. Ours is a statistical approach that uses Monte Carlo simulation to approximate the sampling distribution of the retrieved estimates. We will discuss the strengths and weaknesses of this approach, and provide a case-study example from the Orbiting Carbon Observatory 2 mission.

Satellite-tracking and earth-dynamics research programs. [NASA Programs on satellite orbits and satellite ground tracks of geodetic satellites

NASA Technical Reports Server (NTRS)

1974-01-01

Observations and research progress of the Smithsonian Astrophysical Observatory are reported. Satellite tracking networks (ground stations) are discussed and equipment (Baker-Nunn cameras) used to observe the satellites is described. The improvement of the accuracy of a laser ranging system of the ground stations is discussed. Also, research efforts in satellite geodesy (tides, gravity anomalies, plate tectonics) is discussed. The use of data processing for geophysical data is examined, and a data base for the Earth and Ocean Physics Applications Program is proposed. Analytical models of the earth's motion (computerized simulation) are described and the computation (numerical integration and algorithms) of satellite orbits affected by the earth's albedo, using computer techniques, is also considered. Research efforts in the study of the atmosphere are examined (the effect of drag on satellite motion), and models of the atmosphere based on satellite data are described.

Forward problem studies of electrical resistance tomography system on concrete materials

NASA Astrophysics Data System (ADS)

Ang, Vernoon; Rahiman, M. H. F.; Rahim, R. A.; Aw, S. R.; Wahab, Y. A.; Thomas W. K., T.; Siow, L. T.

2017-03-01

Electrical resistance tomography (ERT) is well known as non-invasive imaging technique, inexpensive, radiation free, visualization measurements of the multiphase flows and frequently applied in geophysical, medical and Industrial Process Tomography (IPT) applications. Application of ERT in concrete is a new exploration field, which can be used in monitoring and detecting the health and condition of concrete without destroying it. In this paper, ERT model under the condition of concrete is studied in which the sensitivity field model is produced and simulated by using COMSOL software. The affects brought by different current injection values with different concrete conductivity are studied in detail. This study able to provide the important direction for the further study of inverse problem in ERT system. Besides, the results of this technique hopefully can open a new exploration in inspection method of concrete structures in order to maintain the health of the concrete structure for civilian safety.

Introduction to the JEEG Agricultural Geophysics Special Issue

USGS Publications Warehouse

Allred, Barry J.; Smith, Bruce D.

2010-01-01

Near-surface geophysical methods have become increasingly important tools in applied agricultural practices and studies. The great advantage of geophysical methods is their potential rapidity, low cost, and spatial continuity when compared to more traditional methods of assessing agricultural land, such as sample collection and laboratory analysis. Agricultural geophysics investigations commonly focus on obtaining information within the soil profile, which generally does not extend much beyond 2 meters beneath the ground surface. Although the depth of interest oftentimes is rather shallow, the area covered by an agricultural geophysics survey can vary widely in scale, from experimental plots (10 s to 100 s of square meters), to farm fields (10 s to 100 s of hectares), up to the size of watersheds (10 s to 100 s of square kilometers). To date, three predominant methods—resistivity, electromagnetic induction (EMI), and ground-penetrating radar (GPR)—have been used to obtain surface-based geophysical measurements within agricultural settings. However, a recent conference on agricultural geophysics (Bouyoucos Conference on Agricultural Geophysics, September 8–10, 2009, Albuquerque, New Mexico; www.ag-geophysics.org) illustrated that other geophysical methods are being applied or developed. These include airborne electromagnetic induction, magnetometry, seismic, and self-potential methods. Agricultural geophysical studies are also being linked to ground water studies that utilize deeper penetrating geophysical methods than normally used.

The role of instruments in the history of Geophysics: the case of Seismology

NASA Astrophysics Data System (ADS)

Ferrari, Graziano

2015-04-01

Science is the study that leads to discriminate knowledge of the material world based on observation, experiment and induction. Geophysics is the combination of the former concern about the explanation of every day phenomena in our enviroment, with the achievements of physics that were exploited within the laboratory, either by experiments or by theoreticians. Unlike other disciplines such as physics or chemistry, geophysics is a mosaic of disciplines also very different among each other. The main differences concern the object and method of study or the evolutionary path. Many cyclic phenomena of the Earth are long-term processes so that a long period of study is essential to a thorough understanding. Extreme natural events such as earthquakes, volcanic eruptions, floods, etc. significantly contribute to the natural hazards. So, in seismology, volcanology, hydrogeology, as in those disciplines who study significant changes in climate or in geomagnetism, long time series of data are very useful, along with the instruments that registered them and the scientific paradigms within which they were produced. These aspects, contributing to the history of geophysics, are extremely useful especially for the fallout on the mankind's life and activities.To be useful, as well as the recovery, the historical data must be "normalized" to the current use we want to do of them. This process makes an essential contribution to knowledge of the instruments that recorded this data: their principles of operation, their constants and their variability over time. Many of the disciplines involved in geophysics, as seismology, geomagnetism, etc. require observations both geographically distributed and synchronized. Geomagnetic and seismological recordings, together with astronomical and meteorological observations have been frequently done in the same observatories, in the past. Despite their relative cyclic nature, since earthquakes may not occur in the exact same way, thorough analysis of earthquakes of the past are particularly important. The reconstruction of a history of instrumental seismology, of its most important turning points, of the mutual inspiration between theories and experiments, and the recovery and current scientific use of its data will be presented.

Geophysical Methods for Monitoring Soil Stabilization Processes

EPA Science Inventory

Soil stabilization involves methods used to turn unconsolidated and unstable soil into a stiffer, consolidated medium that could support engineered structures, alter permeability, change subsurface flow, or immobilize contamination through mineral precipitation. Among the variety...

Geophysical Observatory in Kamchatka region for monitoring of phenomena connected with seismic activity

NASA Astrophysics Data System (ADS)

Uyeda, S.; Nagao, T.; Hattori, K.; Hayakawa, M.; Miyaki, K.; Molchanov, O.; Gladychev, V.; Baransky, L.; Chtchekotov, A.; Fedorov, E.; Pokhotelov, O.; Andreevsky, S.; Rozhnoi, A.; Khabazin, Y.; Gorbatikov, A.; Gordeev, E.; Chebrov, V.; Sinitzin, V.; Lutikov, A.; Yunga, S.; Kosarev, G.; Surkov, V.; Belyaev, G.

Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range ∆F = 0.5 - 40 Hz) and meteorological recordings, together with seismo-acoustic (∆F = 30 - 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations ( ∆F = 0.003 - 30 Hz), three-component electric potential variations ( ∆F < 1.0 Hz), and VLF transmitter's signal perturbations ( ∆F ~ 10 - 40 kHz).

The geophysical processor system: Automated analysis of ERS-1 SAR imagery

NASA Technical Reports Server (NTRS)

Stern, Harry L.; Rothrock, D. Andrew; Kwok, Ronald; Holt, Benjamin

1994-01-01

The Geophysical Processor System (GPS) at the Alaska (U.S.) SAR (Synthetic Aperture Radar) Facility (ASF) uses ERS-1 SAR images as input to generate three types of products: sea ice motion, sea ice type, and ocean wave spectra. The GPS, operating automatically with minimal human intervention, delivers its output to the Archive and Catalog System (ACS) where scientists can search and order the products on line. The GPS has generated more than 10,000 products since it became operational in Feb. 1992, and continues to deliver 500 new products per month to the ACS. These products cover the Beaufort and Chukchi Seas and the western portion of the central Arctic Ocean. More geophysical processing systems are needed to handle the large volumes of data from current and future satellites. Images must be routinely and consistently analyzed to yield useful information for scientists. The current GPS is a good, working prototype on the way to more sophisticated systems.

Use of Seafloor Electromagnetic and Acoustic Backscatter Data for Seafloor Classification: An Example From Martha's Vineyard, Massachusetts.

NASA Astrophysics Data System (ADS)

Evans, R. L.; Kraft, B.; Mayer, L.

2006-12-01

Near surface offshore geophysical data allow sediment classification in coastal settings at high levels of spatial detail. We present data from offshore Martha's Vineyard, Massachusetts collected as part of the Office of Naval Researchś Mine Burial Prediction program. Seafloor electromagnetic data provide estimates of near surface porosity at approximately 10m intervals along each tow-line. In addition, the area has undergone repeat surveys with high resolution acoustic backscatter and bathymetry. In some locations, the geophysical data has been groundtruthed by grab sampling and coring. We examine the spatial variability in near surface sediment properties on the basis of the geophysical data. The EM data are particularly well suited to constructing semi-variograms to display length scales of variability. Preliminary examination does not show any obvious correlation between the EM data and acoustic backscatter, however, further processing of the backscatter is being carried out and so this result is tentative.

Publications - GPR 2015-5 | Alaska Division of Geological & Geophysical

Science.gov Websites

Geologic Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey electromagnetic and magnetic airborne geophysical survey data compilation Authors: Burns, L.E., Geoterrex-Dighem Graham, G.R.C., 2015, Livengood mining district electromagnetic and magnetic airborne geophysical survey

Publications - GPR 2015-6 | Alaska Division of Geological & Geophysical

Science.gov Websites

Geologic Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey content DGGS GPR 2015-6 Click to enlarge Publication Details Title: Airborne magnetic geophysical survey ., Graham, Gina, and Goldak Airborne Surveys, 2015, Airborne magnetic geophysical survey of the Tanacross

Phillips Laboratory Geophysics Scholar Program

DTIC Science & Technology

1993-09-30

research at Phillips Laboratory . Research sponsored by Air Force Geophysics Laboratory ...Geophysics Laboratory (now the Phillips Laboratory , Geophysics Directorate), United States Air Force for its sponsorship of this research through the Air ...September 1993 Approved for public release; distribution unlimited PHILLIPS LABORATORY Directorate of Geophysics AIR FORCE MATERIEL COMMAND

Spatial and temporal distributions of Martian north polar cold spots before, during, and after the global dust storm of 2001

USGS Publications Warehouse

Cornwall, C.; Titus, T.N.

2009-01-01

In the 1970s, Mariner and Viking observed features in the Mars northern polar region that were a few hundred kilometers in diameter with 20 fj,m brightness temperatures as low as 130 K (considerably below C02 ice sublimation temperatures). Over the past decade, studies have shown that these areas (commonly called "cold spots") are usually due to emissivity effects of frost deposits and occasionally to active C02 snowstorms. Three Mars years of Mars Global Surveyor Thermal Emission Spectrometer data were used to observe autumn and wintertime cold spot activity within the polar regions. Many cold spots formed on or near scarps of the perennial cap, probably induced by adiabatic cooling due to orographic lifting. These topographically associated cold spots were often smaller than those that were not associated with topography. We determined that initial grain sizes within the cold spots were on the order of a few millimeters, assuming the snow was uncontaminated by dust or water ice. On average, the half-life of the cold spots was 5 Julian days. The Mars global dust storm in 2001 significantly affected cold spot activity in the north polar region. Though overall perennial cap cold spot activity seemed unaffected, the distribution of cold spots did change by a decrease in the number of topographically associated cold spots and an increase in those not associated with topography. We propose that the global dust storm affected the processes that form cold spots and discuss how the global dust storm may have affected these processes. ?? 2009 by the American Geophysical Union.

Extracting Independent Local Oscillatory Geophysical Signals by Geodetic Tropospheric Delay

NASA Technical Reports Server (NTRS)

Botai, O. J.; Combrinck, L.; Sivakumar, V.; Schuh, H.; Bohm, J.

2010-01-01

Zenith Tropospheric Delay (ZTD) due to water vapor derived from space geodetic techniques and numerical weather prediction simulated-reanalysis data exhibits non-linear and non-stationary properties akin to those in the crucial geophysical signals of interest to the research community. These time series, once decomposed into additive (and stochastic) components, have information about the long term global change (the trend) and other interpretable (quasi-) periodic components such as seasonal cycles and noise. Such stochastic component(s) could be a function that exhibits at most one extremum within a data span or a monotonic function within a certain temporal span. In this contribution, we examine the use of the combined Ensemble Empirical Mode Decomposition (EEMD) and Independent Component Analysis (ICA): the EEMD-ICA algorithm to extract the independent local oscillatory stochastic components in the tropospheric delay derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) over six geodetic sites (HartRAO, Hobart26, Wettzell, Gilcreek, Westford, and Tsukub32). The proposed methodology allows independent geophysical processes to be extracted and assessed. Analysis of the quality index of the Independent Components (ICs) derived for each cluster of local oscillatory components (also called the Intrinsic Mode Functions (IMFs)) for all the geodetic stations considered in the study demonstrate that they are strongly site dependent. Such strong dependency seems to suggest that the localized geophysical signals embedded in the ZTD over the geodetic sites are not correlated. Further, from the viewpoint of non-linear dynamical systems, four geophysical signals the Quasi-Biennial Oscillation (QBO) index derived from the NCEP/NCAR reanalysis, the Southern Oscillation Index (SOI) anomaly from NCEP, the SIDC monthly Sun Spot Number (SSN), and the Length of Day (LoD) are linked to the extracted signal components from ZTD. Results from the synchronization analysis show that ZTD and the geophysical signals exhibit (albeit subtle) site dependent phase synchronization index.

Time-lapse integrated geophysical imaging of magmatic injections and fluid-induced fracturing causing Campi Flegrei 1983-84 Unrest

NASA Astrophysics Data System (ADS)

De Siena, Luca; Crescentini, Luca; Amoruso, Antonella; Del Pezzo, Edoardo; Castellano, Mario

2016-04-01

Geophysical precursors measured during Unrest episodes are a primary source of geophysical information to forecast eruptions at the largest and most potentially destructive volcanic calderas. Despite their importance and uniqueness, these precursors are also considered difficult to interpret and unrepresentative of larger eruptive events. Here, we show how novel geophysical imaging and monitoring techniques are instead able to represent the dynamic evolution of magmatic- and fluid-induced fracturing during the largest period of Unrest at Campi Flegrei caldera, Italy (1983-1984). The time-dependent patterns drawn by microseismic locations and deformation, once integrated by 3D attenuation tomography and absorption/scattering mapping, model injections of magma- and fluid-related materials in the form of spatially punctual microseismic bursts at a depth of 3.5 km, west and offshore the city of Pozzuoli. The shallowest four kilometres of the crust work as a deformation-based dipolar system before and after each microseismic shock. Seismicity and deformation contemporaneously focus on the point of injection; patterns then progressively crack the medium directed towards the second focus, a region at depths 1-1.5 km south of Solfatara. A single high-absorption and high-scattering aseismic anomaly marks zones of fluid storage overlying the first dipolar centre. These results provide the first direct geophysical signature of the processes of aseismic fluid release at the top of the basaltic basement, producing pozzolanic activity and recently observed via rock-physics and well-rock experiments. The microseismicity caused by fluids and gasses rises to surface via high-absorption north-east rising paths connecting the two dipolar centres, finally beingq being generally expelled from the maar diatreme Solfatara structure. Geophysical precursors during Unrest depict how volcanic stress was released at the Campi Flegrei caldera during its period of highest recorded seismicity and deformation; they may work as a template for modelling future events in the case the volcano was approaching eruption conditions.

Submarine geology and geomorphology of active Sub-Antarctic volcanoes: Heard and McDonald Islands

NASA Astrophysics Data System (ADS)

Watson, S. J.; Coffin, M. F.; Whittaker, J. M.; Lucieer, V.; Fox, J. M.; Carey, R.; Arculus, R. J.; Bowie, A. R.; Chase, Z.; Robertson, R.; Martin, T.; Cooke, F.

2016-12-01

Heard and McDonald Islands (HIMI) are World Heritage listed sub-Antarctic active volcanic islands in the Southern Indian Ocean. Built atop the Kerguelen Plateau by Neogene-Quaternary volcanism, HIMI represent subaerial exposures of the second largest submarine Large Igneous Province globally. Onshore, processes influencing island evolution include glaciers, weathering, volcanism, vertical tectonics and mass-wasting (Duncan et al. 2016). Waters surrounding HIMI are largely uncharted, due to their remote location. Hence, the extent to which these same processes shape the submarine environment around HIMI has not been investigated. In early 2016, we conducted marine geophysical and geologic surveys around HIMI aboard RV Investigator (IN2016_V01). Results show that volcanic and sedimentary features prominently trend east-west, likely a result of erosion by the eastward flowing Antarctic Circumpolar Current and tidal currents. However, spatial patterns of submarine volcanism and sediment distribution differ substantially between the islands. >70 sea knolls surround McDonald Island suggesting substantial submarine volcanism. Geophysical data reveals hard volcanic seafloor around McDonald Island, whereas Heard Island is characterised by sedimentary sequences tens of meters or more thick and iceberg scours - indicative of glacial processes. Differences in submarine geomorphology are likely due to the active glaciation of Heard Island and differing rock types (Heard: alkali basalt, McDonald: phonolite), and dominant products (clastics vs. lava). Variations may also reflect different magmatic plumbing systems beneath the two active volcanoes (Heard produces larger volumes of more focused lava, whilst McDonald extrudes smaller volumes of more evolved lavas from multiple vents across the edifice). Using geophysical data, corroborated with new and existing geologic data, we present the first geomorphic map revealing the processes that shape the submarine environment around HIMI.

High-Precision and Low Latency RT-GNSS Processed Data for Diverse Geophysical and Natural Hazard Communities.

NASA Astrophysics Data System (ADS)

Mencin, David; Hodgkinson, Kathleen; Sievers, Charlie; David, Phillips; Charles, Meertens; Glen, Mattioli

2017-04-01

UNAVCO has been providing infrastructure and support for solid-earth sciences and earthquake natural hazards for the past two decades. Recent advances in GNSS technology and data processing are now providing position solutions with centimeter-level precision at high-rate (>1 Hz) and low latency (i.e. the time required for data to arrive for analysis, in this case less than 1 second). These data have the potential to improve our understanding in diverse areas of geophysics including properties of seismic, volcanic, magmatic and tsunami sources, and thus profoundly transform rapid event characterization and warning. Scientific and operational applications also include glacier and ice sheet motions; tropospheric modeling; and space weather. These areas of geophysics represent a spectrum of research fields, including geodesy, seismology, tropospheric weather, space weather and natural hazards. Processed Real-Time GNSS (RT-GNSS) data will require formats and standards that allow this broad and diverse community to use these data and associated meta-data in existing research infrastructure. These advances have critically highlighted the difficulties associated with merging data and metadata between scientific disciplines. Even seemingly very closely related fields such as geodesy and seismology, which both have rich histories of handling large volumes of data and metadata, do not go together well in any automated way. Community analysis strategies, or lack thereof, such as treatment of error prove difficult to address and are reflected in the data and metadata. In addition, these communities have differing security, accessibility and reliability requirements. We propose some solutions to the particular problem of making RT-GNSS processed solution data and metadata accessible to multiply scientific and natural hazard communities. Importantly, we discuss the roadblocks encounter and solved and those that remain to be addressed.

New Hydrologic Insights to Advance Geophysical Investigation of the Unsaturated Zone

NASA Astrophysics Data System (ADS)

Nimmo, J. R.; Perkins, K. S.

2015-12-01

Advances in hydrology require information from the unsaturated zone, especially for problems related to groundwater contamination, water-supply sustainability, and ecohydrology. Unsaturated-zone processes are notoriously difficult to quantify; soils and rocks are visually opaque, spatially variable in the extreme, and easily disturbed by instrument installation. Thus there is great value in noninvasive techniques that produce water-related data of high density in space and time. Methods based on resistivity and electromagnetic waves have already produced significant new understanding of percolation processes, root-zone water retention, influences of evapotranspiration on soil-water, and effects of preferential flow. Further developments are underway for such purposes as noninvasive application to greater depths, increased resolution, adaptation for lab-scale experiments, and calibration in heterogeneous media. Beyond these, however, there is need for a stronger marriage of hydrologic and geophysical knowledge and perspective. Possible means to greater and faster progress include: Apply the latest hydrologic understanding, both pore-scale and macroscopic, to the detection of preferential flow paths and their degree of activation. In the continuing advancement of hardware and techniques, draw creatively from developments in such fields as high-energy physics, medical imaging, astrogeology, high-tech semiconductors, and bioinstrumentation. Sidestep the imaging process where possible to measure essential properties and fluxes more directly. Pose questions that have a strong end-use character, like "how does storm intensity relate to aquifer recharge rate" rather than "what is the shape of the wetting front". The greatest advances in geophysical investigation of the unsaturated zone will come from methods informed by the latest understanding of unsaturated systems and processes, and aimed as directly as possible at the answers to important hydrologic questions.

Marine geophysical data collected in a shallow back-barrier estuary, Barnegat Bay, New Jersey

USGS Publications Warehouse

Andrews, Brian D.; Miselis, Jennifer L.; Danforth, William W.; Irwin, Barry J.; Worley, Charles R.; Bergeron, Emile M.; Blackwood, Dann S.

2015-06-26

In 2011, the U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection, began a multidisciplinary research project to better understand the water quality in Barnegat Bay, New Jersey. This back-barrier estuary is experiencing degraded water quality, algal blooms, loss of seagrass, and increases in oxygen stress, macroalgae, stinging nettles, and brown tide. The spatial scale of the estuary and the scope of challenges within it necessitate a multidisciplinary approach that includes establishing the regional geology and the estuary’s physical characteristics and modeling how the estuary’s morphology interacts to affect its water quality. This report presents the data collected during this project for use in understanding the morphology and the distribution of sea-floor and sub-sea-floor sediments within Barnegat Bay, describes the methods used to collect and process those data, and includes links to the final processed datasets. These data can be used by scientists to understand the links between geomorphology, geologic framework, sediment transport, and estuarine water quality and circulation.

Toward Robust Climate Baselining: Objective Assessment of Climate Change Using Widely Distributed Miniaturized Sensors for Accurate World-Wide Geophysical Measurements

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

Teller, E; Leith, C; Canavan, G

A gap-free, world-wide, ocean-, atmosphere-, and land surface-spanning geophysical data-set of three decades time-duration containing the full set of geophysical parameters characterizing global weather is the scientific perquisite for defining the climate; the generally-accepted definition in the meteorological community is that climate is the 30-year running-average of weather. Until such a tridecadal climate base line exists, climate change discussions inevitably will have a semi-speculative, vs. a purely scientific, character, as the baseline against which changes are referenced will be at least somewhat uncertain. The contemporary technology base provides ways-and-means for commencing the development of such a meteorological measurement-intensive climate baseline, moreover with a program budget far less than the {approx}more » $2.5 B/year which the US. currently spends on ''global change'' studies. In particular, the recent advent of satellite-based global telephony enables real-time control of, and data-return from, instrument packages of very modest scale, and Silicon Revolution-based sensor, data-processing and -storage advances permit 'intelligent' data-gathering payloads to be created with 10 gram-scale mass budgets. A geophysical measurement system implemented in such modern technology is a populous constellation 03 long-lived, highly-miniaturized robotic weather stations deployed throughout the weather-generating portions of the Earths atmosphere, throughout its oceans and across its land surfaces. Leveraging the technological advances of the OS, the filly-developed atmospheric weather station of this system has a projected weight of the order of 1 ounce, and contains a satellite telephone, a GPS receiver, a full set of atmospheric sensing instruments and a control computer - and has an operational life of the order of 1 year and a mass-production cost of the order of $$20. Such stations are effectively ''intra-atmospheric satellites'' but likely have serial-production unit costs only about twenty-billionths that of a contemporary NASA global change satellite, whose entirely-remote sensing capabilities they complement with entirely-local sensing. It's thus feasible to deploy millions of them, and thereby to intensively monitor all aspects of the Earths weather. Analogs of these atmospheric weather stations will be employed to provide comparable-quality reporting of oceanic and land-surface geophysical parameters affecting weather. This definitive climate baselining system could be in initial-prototype operation on a one-year time-scale, and in intermediate-scale, proof-of-principle operation within three years, at a total cost of {approx}$$95M. Steady-state operating costs are estimated to be {approx} $$75M/year, or {approx}3% of the current US. ''global change'' program-cost. Its data-return would be of great value very quickly as simply the best weather information, and within a few years as the definitive climatic variability-reporting system. It would become the generator of a definitive climate baseline at a total present-value cost of {approx}$$0.9 B.« less

Processing EOS MLS Level-2 Data

NASA Technical Reports Server (NTRS)

Snyder, W. Van; Wu, Dong; Read, William; Jiang, Jonathan; Wagner, Paul; Livesey, Nathaniel; Schwartz, Michael; Filipiak, Mark; Pumphrey, Hugh; Shippony, Zvi

2006-01-01

A computer program performs level-2 processing of thermal-microwave-radiance data from observations of the limb of the Earth by the Earth Observing System (EOS) Microwave Limb Sounder (MLS). The purpose of the processing is to estimate the composition and temperature of the atmosphere versus altitude from .8 to .90 km. "Level-2" as used here is a specialists f term signifying both vertical profiles of geophysical parameters along the measurement track of the instrument and processing performed by this or other software to generate such profiles. Designed to be flexible, the program is controlled via a configuration file that defines all aspects of processing, including contents of state and measurement vectors, configurations of forward models, measurement and calibration data to be read, and the manner of inverting the models to obtain the desired estimates. The program can operate in a parallel form in which one instance of the program acts a master, coordinating the work of multiple slave instances on a cluster of computers, each slave operating on a portion of the data. Optionally, the configuration file can be made to instruct the software to produce files of simulated radiances based on state vectors formed from sets of geophysical data-product files taken as input.

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

Syracuse, Ellen Marie; Maceira, Monica; Phillips, William Scott

These are slides which show many graphs and datasets for the above-mentioned topic and then concludes with the following: Joint inversion of multiple geophysical datasets improves recovery of velocity structures, particularly in Vs and in shallow parts of the model, in comparison to travel-time only models. Resulting fits to travel time data are minimally degraded by joint inversions. Correspondingly, fits to independent estimates of ground-truth locations are minimally affected by joint inversions.

Contribution of Small-Scale Correlated Fluctuations of Microstructural Properties of a Spatially Extended Geophysical Target Under the Assessment of Radar Backscatter

NASA Technical Reports Server (NTRS)

Yurchak, Boris S.

2010-01-01

The study of the collective effects of radar scattering from an aggregation of discrete scatterers randomly distributed in a space is important for better understanding the origin of the backscatter from spatially extended geophysical targets (SEGT). We consider the microstructure irregularities of a SEGT as the essential factor that affect radar backscatter. To evaluate their contribution this study uses the "slice" approach: particles close to the front of incident radar wave are considered to reflect incident electromagnetic wave coherently. The radar equation for a SEGT is derived. The equation includes contributions to the total backscatter from correlated small-scale fluctuations of the slice's reflectivity. The correlation contribution changes in accordance with an earlier proposed idea by Smith (1964) based on physical consideration. The slice approach applied allows parameterizing the features of the SEGT's inhomogeneities.

1986 eruption of Augustine Volcano: Public safety response by Alaskan volcanologists

NASA Astrophysics Data System (ADS)

Kienle, J.; Davies, J. N.; Miller, T. P.; Yount, M. E.

Although, in a general sense, all scientific work on hazardous natural phenomena such as weather, earthquakes, and volcanic eruptions can advance the public safely, we wish to describe some specific actions that were motivated by direct considerations of safety. These kinds of actions are normally at the fringes of scientific research and become important only during some crisis; in this instance, the crisis was the eruption on March 27, 1986, of Augustine Volcano (Figure 1). The agencies involved were the Geophysical Institute of the University of Alaska (UAGI), the Division of Geological and Geophysical Surveys of the State of Alaska (DGGS), and the Alaska Branch of the United States Geological Survey (USGS). The central theme of our mutual effort during the crisis was to communicate to response agencies and the public, in the most meaningful way possible, a prediction of what could happen next and how it would affect the public.

Implications of Lunar Prospector Data for Lunar Geophysics

NASA Technical Reports Server (NTRS)

Zuber, Maria

2003-01-01

Research is sumamrized in the following areas: The Asymmetric Thermal Evolution of the Moon; Magma Transport Process on the Moon;The Composition and Origin of the Deep Lunar Crust;The Redistribution of Thorium on the Moon's Surface.

Activities at the Lunar and Planetary Institute

NASA Technical Reports Server (NTRS)

Burke, K.

1984-01-01

The scientific and administrative activities of the Lunar and Planetary Institute are summarized. Recent research relating to geophysics, planetary geology, the origin of the Earth and Moon, the lunar surface, Mars, meteorites, and image processing techniques is discussed.

Influence of heating experiments on parameters of Schumann resonances

NASA Astrophysics Data System (ADS)

Agranat, Irina; Sivokon, Vladimir

2017-10-01

Recently the significant increase in intensity of researches in the field of the fissile impact on geophysical processes in various environments is noted. Special attention is paid to a research of impact on an ionosphere of a potent short-wave radio emission of heating stands. Today experiments on change of an ionosphere are made generally at stands HAARP, EISCAT in Tromse (Norway). Within the Russian campaign (Tomsk) EISCAT/heating (AARI_HFOX) made from October 19 to October 30, 2016 experiments on impact on an ionosphere F-layer by the radiation potent HF. For assessment of impact of these experiments on geophysical processes mathematical methods carried out the analysis of change of the parameters of the Schumann resonances received on the basis of data from the station of constant observation of the Schumann resonances in the city of Tomsk, the Tomsk State University (Russia).

Geophysical bed sediment characterization of the Androscoggin River from the former Chlor-Alkali Facility Superfund Site, Berlin, New Hampshire, to the state border with Maine, August 2009

USGS Publications Warehouse

Degnan, James R.; Teeple, Andrew; Johnston, Craig M.; Marvin-DiPasquale, Mark C.; Luce, Darryl

2011-01-01

The former Chlor-Alkali Facility in Berlin, New Hampshire, was listed on the U.S. Environmental Protection Agency National Priorities List in 2005 as a Superfund site. The Chlor-Alkali Facility lies on the east bank of the Androscoggin River. Elemental mercury currently discharges from that bank into the Androscoggin River. The nature, extent, and the speciation of mercury and the production of methyl mercury contamination in the adjacent Androscoggin River is the subject of continuing investigations. The U.S. Geological Survey, in cooperation with Region I of the U.S. Environmental Protection Agency, used geophysical methods to determine the distribution, thickness, and physical properties of sediments in the Androscoggin River channel at a small area of an upstream reference reach and downstream from the site to the New Hampshire–Maine State border. Separate reaches of the Androscoggin River in the study area were surveyed with surface geophysical methods including ground-penetrating radar and step-frequency electromagnetics. Results were processed to assess sediment characteristics including grain size, electrical conductivity, and pore-water specific conductance. Specific conductance measured during surface- and pore-water sampling was used to help interpret the results of the geophysical surveys. The electrical resistivity of sediment samples was measured in the laboratory with intact pore water for comparison with survey results. In some instances, anthropogenic features and land uses, such as roads and power lines affected the detection of riverbed properties using geophysical methods; when this occurred, the data were removed. Through combining results, detailed riverbed sediment characterizations were made. Results from ground-penetrating radar surveys were used to image and measure the depth to the riverbed, depth to buried riverbeds, riverbed thickness and to interpret material-type variations in terms of relative grain size. Fifty two percent of the riverbed in the study area was covered with gravel and finer sediments. The electrically resistive river water and sediment in this study area were conducive to the penetration of the ground-penetrating radar and step-frequency electromagnetic signals and allowed for effective sediment characterization by geophysical methods. The reach between the former Chlor-Alkali Facility and the Riverside Dam, had small areas of fine sediment (estimated 11 percent of riverbed area), found on the upstream left bank and the downstream right bank, with an electromagnetic conductivity (31.4 millisiemens per meter (mS/m) maximum) that was higher than the upstream reference reach. The greatest electromagnetic conductivity (195 mS/m), pore-water specific conductance (324 mS/m) and lab measured sediment conductivity of (76.8 mS/m, measured with a direct-current resistivity test box) in the study were measured approximately 1 mile (mi) downstream of the site from a sandbar on the left bank. Reaches adjacent to and within 2 mi downstream from the site had elevated electromagnetic conductivity despite having lower estimated percentages of riverbed area covered in sediment (11, 25, and 61 percent, respectively) than the reference reach (97). Typically finer grained sediment with similar mineralogy will be more conductive. The Shelburne Reservoir is approximately 8 mi downstream from the site had the second greatest pore-water specific conductance measured, 45.8 mS/m. Many of the locations with the largest step-frequency electromagnetic values have not been sampled for pore water and sediment.

Geophysical methods in Geology. Second edition

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

Sharma, P.V.

This book presents an introduction to the methods of geophysics and their application to geological problems. The text emphasizes the broader aspects of geophysics, including the way in which geophysical methods help solve structural, correlational, and geochromological problems. Stress is laid on the principles and applications of methods rather than on instrumental techniques. This edition includes coverage of recent developments in geophysics and geology. New topics are introduced, including paleomagnetic methods, electromagnetic methods, microplate tectronics, and the use of multiple geophysical techniques.

Integration of remote sensing and ground-based techniques for the study of land degradation phenomena in coastal areas.

NASA Astrophysics Data System (ADS)

Imbrenda, Vito; Coluzzi, Rosa; Calamita, Giuseppe; Luigia Giannossi, Maria; D'Emilio, Mariagrazia; Lanfredi, Maria; Makris, John; Palombo, Angelo; Pascucci, Simone; Santini, Federico; Margiotta, Salvatore; Emanuela Bonomo, Agnese; De Martino, Gregory; Perrone, Angela; Rizzo, Enzo; Pignatti, Stefano; Summa, Vito; Simoniello, Tiziana

2015-04-01

Land degradation processes, such as salinization and waterlogging, are increasingly affecting extensive areas devoted to agriculture threatening the sustainability of farming practices. Soil salinization typically appears as an excess accumulation of salt generally pronounced at the soil surface. Commonly, soil salinity is defined and measured by means of laboratory measurements of the electrical conductivity of liquid extracted from saturated soil-paste or different soil-water suspensions. Lab measurements are generally time consuming, costly, destructive, untimely for practical situations where the determination of the causes and/or the assessment of management practices are of interest. Recently, emerging survey techniques proved to be powerful tools to support soil salinity appraisal reducing costs and increasing the amount of spatial information. In the frame of PRO-LAND project (PO-FESR Basilicata 2007-2013) the research activities have been focused on the study of a complex salinization phenomenon occurring in a coastal environment of the Basilicata region (Southern Italy) as a result of natural and anthropic disturbances. The study area is located in the southernmost part of the Bradanic Trough along the sandy Ionian coastal plain. The hydrogeological conditions affect shallowness of the aquifer (45-50 cm below the ground) allowing the occurrence of seawater intrusion. Moreover, during last century, human activities, i.e. built-up of dams, the emergence of farms and industries, played a relevant role in the alteration of soil and groundwater quality of the area. In this work, both ground-based and remote sensing data were used. First, a geophysical mapping of electrical conductivity was carried out using a multi-frequency portable electro-magnetic induction (EMI) sensor. Based on the geophysical mapping and on optimization sampling approach, a number of locations were identified to collect soil samples for the geomineralogical characterization. Airborne images were acquired on the study area by the hyperspectral Compact Airborne Spectrographic Imager (CASI) - 1500 to derive indices sensitive to soil degradation. The main aim of this research activity was to improve the knowledge about the most relevant driving forces, contributing to the analyzed degradation process, and their interplay within the study area. In the light of this, we also would like to suggest the most appropriate best practices and restoration activities to be undertaken.

Production and Distribution of NASA MODIS Remote Sensing Products

NASA Technical Reports Server (NTRS)

Wolfe, Robert

2007-01-01

The two Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on-board NASA's Earth Observing System (EOS) Terra and Aqua satellites make key measurements for understanding the Earth's terrestrial ecosystems. Global time-series of terrestrial geophysical parameters have been produced from MODIS/Terra for over 7 years and for MODIS/Aqua for more than 4 1/2 years. These well calibrated instruments, a team of scientists and a large data production, archive and distribution systems have allowed for the development of a new suite of high quality product variables at spatial resolutions as fine as 250m in support of global change research and natural resource applications. This talk describes the MODIS Science team's products, with a focus on the terrestrial (land) products, the data processing approach and the process for monitoring and improving the product quality. The original MODIS science team was formed in 1989. The team's primary role is the development and implementation of the geophysical algorithms. In addition, the team provided feedback on the design and pre-launch testing of the instrument and helped guide the development of the data processing system. The key challenges the science team dealt with before launch were the development of algorithms for a new instrument and provide guidance of the large and complex multi-discipline processing system. Land, Ocean and Atmosphere discipline teams drove the processing system requirements, particularly in the area of the processing loads and volumes needed to daily produce geophysical maps of the Earth at resolutions as fine as 250 m. The processing system had to handle a large number of data products, large data volumes and processing loads, and complex processing requirements. Prior to MODIS, daily global maps from heritage instruments, such as Advanced Very High Resolution Radiometer (AVHRR), were not produced at resolutions finer than 5 km. The processing solution evolved into a combination of processing the lower level (Level 1) products and the higher level discipline specific Land and Atmosphere products in the MODIS Science Investigator Lead Processing System (SIPS), the MODIS Adaptive Processing System (MODAPS), and archive and distribution of the Land products to the user community by two of NASA s EOS Distributed Active Archive Centers (DAACs). Recently, a part of MODAPS, the Level 1 and Atmosphere Archive and Distribution System (LAADS), took over the role of archiving and distributing the Level 1 and Atmosphere products to the user community.

TOPEX Software Document Series. Volume 5; Rev. 1; TOPEX GDR Processing

NASA Technical Reports Server (NTRS)

Lee, Jeffrey; Lockwood, Dennis; Hancock, David W., III

2003-01-01

This document is a compendium of the WFF TOPEX Software Development Team's knowledge regarding Geophysical Data Record (GDR) Processing. It includes many elements of a requirements document, a software specification document, a software design document, and a user's manual. In the more technical sections, this document assumes the reader is familiar with TOPEX and instrument files.

Geophysical study of the structure and processes of the continental convergence zones: Alpine-Himalayan Belt

NASA Technical Reports Server (NTRS)

Toksoz, M. Nafi; Molnar, Peter

1988-01-01

Intracontinental deformation occurrence and the processes and physical parameters that control the rates and styles of deformation were examined. Studies addressing specific mechanical aspects of deformation were reviewed and the studies of deformation and of the structure of specific areas were studied considering the strength of the material and the gravitational effect.

30 CFR 251.11 - Submission, inspection, and selection of geological data and information collected under a permit...

Code of Federal Regulations, 2010 CFR

2010-07-01

... geological data and information collected under a permit and processed by permittees or third parties. 251.11... GEOLOGICAL AND GEOPHYSICAL (G&G) EXPLORATIONS OF THE OUTER CONTINENTAL SHELF § 251.11 Submission, inspection, and selection of geological data and information collected under a permit and processed by permittees...

Developing integrated methods to address complex resource and environmental issues

USGS Publications Warehouse

Smith, Kathleen S.; Phillips, Jeffrey D.; McCafferty, Anne E.; Clark, Roger N.

2016-02-08

IntroductionThis circular provides an overview of selected activities that were conducted within the U.S. Geological Survey (USGS) Integrated Methods Development Project, an interdisciplinary project designed to develop new tools and conduct innovative research requiring integration of geologic, geophysical, geochemical, and remote-sensing expertise. The project was supported by the USGS Mineral Resources Program, and its products and acquired capabilities have broad applications to missions throughout the USGS and beyond.In addressing challenges associated with understanding the location, quantity, and quality of mineral resources, and in investigating the potential environmental consequences of resource development, a number of field and laboratory capabilities and interpretative methodologies evolved from the project that have applications to traditional resource studies as well as to studies related to ecosystem health, human health, disaster and hazard assessment, and planetary science. New or improved tools and research findings developed within the project have been applied to other projects and activities. Specifically, geophysical equipment and techniques have been applied to a variety of traditional and nontraditional mineral- and energy-resource studies, military applications, environmental investigations, and applied research activities that involve climate change, mapping techniques, and monitoring capabilities. Diverse applied geochemistry activities provide a process-level understanding of the mobility, chemical speciation, and bioavailability of elements, particularly metals and metalloids, in a variety of environmental settings. Imaging spectroscopy capabilities maintained and developed within the project have been applied to traditional resource studies as well as to studies related to ecosystem health, human health, disaster assessment, and planetary science. Brief descriptions of capabilities and laboratory facilities and summaries of some applications of project products and research findings are included in this circular. The work helped support the USGS mission to “provide reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.” Activities within the project include the following:Spanned scales from microscopic to planetary;Demonstrated broad applications across disciplines;Included life-cycle studies of mineral resources;Incorporated specialized areas of expertise in applied geochemistry including mineralogy, hydrogeology, analytical chemistry, aqueous geochemistry, biogeochemistry, microbiology, aquatic toxicology, and public health; andIncorporated specialized areas of expertise in geophysics including magnetics, gravity, radiometrics, electromagnetics, seismic, ground-penetrating radar, borehole radar, and imaging spectroscopy.This circular consists of eight sections that contain summaries of various activities under the project. The eight sections are listed below:Laboratory Facilities and Capabilities, which includes brief descriptions of the various types of laboratories and capabilities used for the project;Method and Software Development, which includes summaries of remote-sensing, geophysical, and mineralogical methods developed or enhanced by the project;Instrument Development, which includes descriptions of geophysical instruments developed under the project;Minerals, Energy, and Climate, which includes summaries of research that applies to mineral or energy resources, environmental processes and monitoring, and carbon sequestration by earth materials;Element Cycling, Toxicity, and Health, which includes summaries of several process-oriented geochemical and biogeochemical studies and health-related research activities;Hydrogeology and Water Quality, which includes descriptions of innovative geophysical, remote-sensing, and geochemical research pertaining to hydrogeology and water-quality applications;Hazards and Disaster Assessment, which includes summaries of research and method development that were applied to natural hazards, human-caused hazards, and disaster assessments; andDatabases and Framework Studies, which includes descriptions of fundamental applications of geophysical studies and of the importance of archived data.

Spatial scale analysis in geophysics - Integrating surface and borehole geophysics in groundwater studies

USGS Publications Warehouse

Paillet, Frederick L.; Singhroy, V.H.; Hansen, D.T.; Pierce, R.R.; Johnson, A.I.

2002-01-01

Integration of geophysical data obtained at various scales can bridge the gap between localized data from boreholes and site-wide data from regional survey profiles. Specific approaches to such analysis include: 1) comparing geophysical measurements in boreholes with the same measurement made from the surface; 2) regressing geophysical data obtained in boreholes with water-sample data from screened intervals; 3) using multiple, physically independent measurements in boreholes to develop multivariate response models for surface geophysical surveys; 4) defining subsurface cell geometry for most effective survey inversion methods; and 5) making geophysical measurements in boreholes to serve as independent verification of geophysical interpretations. Integrated analysis of surface electromagnetic surveys and borehole geophysical logs at a study site in south Florida indicates that salinity of water in the surficial aquifers is controlled by a simple wedge of seawater intrusion along the coast and by a complex pattern of upward brine seepage from deeper aquifers throughout the study area. This interpretation was verified by drilling three additional test boreholes in carefully selected locations.

Lunar Global Heat Flow: Predictions and Constraints

NASA Astrophysics Data System (ADS)

Siegler, M.; Williams, J. P.; Paige, D. A.; Feng, J.

2017-12-01

The global thermal state of the Moon provides fundamental information on its bulk composition and interior evolution. The Moon is known to have a highly asymmetric surface composition [e.g. Lawrence et al., 2003] and crustal thickness [Wieczorek et al.,2012], which is suspected to result from interior asymmetries [Wieczorek and Phillips, 2000; Laneuville et al., 2013]. This is likely to cause a highly asymmetric surface heat flux, both past and present. Our understanding the thermal evolution and composition of the bulk moon therefore requires a global picture of the present lunar thermal state, well beyond our two-point Apollo era measurement. As on the on the Earth, heat flow measurements need to be taken in carefully selected locations to truly characterize the state of the planet's interior. Future surface heat flux and seismic observations will be affected by the presence of interior temperature and crustal radiogenic anomalies, so placement of such instruments is critically important for understanding the lunar interior. The unfortunate coincidence that Apollo geophysical measurements lie areas within or directly abutting the highly radiogenic, anomalously thin-crusted Procellarum region highlights the importance of location for in situ geophysical study [e.g. Siegler and Smrekar, 2014]. Here we present the results of new models of global lunar geothermal heat flux. We synthesize data from several recent missions to constrain lunar crustal composition, thickness and density to provide global predictions of the surface heat flux of the Moon. We also discuss implications from new surface heat flux constraints from the LRO Diviner Lunar Radiometer Experiment and Chang'E 2 Microwave Radiometer. We will identify areas with the highest uncertainty to provide insight on the placement of future landed geophysical missions, such as the proposed Lunar Geophysical Network, to better aim our future exploration of the Moon.

Human exposure to flash floods Relation between flood parameters and human vulnerability during a storm of September 2002 in Southern France

NASA Astrophysics Data System (ADS)

Ruin, Isabelle; Creutin, Jean-Dominique; Anquetin, Sandrine; Lutoff, Céline

2008-10-01

SummaryThe aim of this paper is to investigate the detailed hydrometeorological circumstances that lead to accidental casualties, and to better understand the prominent physical factors of risk. Based on an event that affected the Gard region (Southern France) in September 2002, it is a first attempt to combine analysis of the physical and human response to Mediterranean storms. After details concerning the methodology (for meteorological, hydrological and casualty analysis), the local context and the event, the authors examine two points: the dynamics of the event (flash-flood and riverine-flood response to the storm) together with human exposure on the one hand, and scale as a critical problem affecting flood risk on the other. This investigation stresses the specificity of small catchments, which are more dangerous both in hydrological and human terms. Moreover, this contribution linking social sciences and geophysics constitutes an important step in what [Morss, R.E., Wilhelmi, O.V., Downton, M.W., Gruntfest, E., 2005. Flood risk, uncertainty, and scientific information for decision making. Bull. Am. Meteor. Soc. 86 (11), 1593-1601] call the "End to end to end" process

Integrated Site Investigation Methods and Modeling: Recent Developments at the BHRS (Invited)

NASA Astrophysics Data System (ADS)

Barrash, W.; Bradford, J. H.; Cardiff, M. A.; Dafflon, B.; Johnson, B. A.; Malama, B.; Thoma, M. J.

2010-12-01

The Boise Hydrogeophysical Research Site (BHRS) is a field-scale test facility in an unconfined aquifer with the goals of: developing cost-effective, non-invasive methods for quantitative characterization of heterogeneous aquifers using hydrologic and geophysical techniques; understanding fundamental relations and processes at multiple scales; and testing theories and models for groundwater flow and solute transport. The design of the BHRS supports a wide range of single-well, cross-hole, multiwell and multilevel hydrologic, geophysical, and combined hydrogeophysical experiments. New installations support direct and geophysical monitoring of hydrologic fluxes and states from the aquifer through the vadose zone to the atmosphere, including ET and river boundary behavior. Efforts to date have largely focused on establishing the 1D, 2D, and 3D distributions of geologic, hydrologic, and geophysical parameters which can then be used as the basis for testing methods to integrate direct and indirect data and invert for “known” parameter distributions, material boundaries, and tracer test or other system state behavior. Aquifer structure at the BHRS is hierarchical and includes layers and lenses that are recognized with geologic, hydrologic, radar, electrical, and seismic methods. Recent advances extend findings and method developments, but also highlight the need to examine assumptions and understand secular influences when designing and modeling field tests. Examples of advances and caveats include: New high-resolution 1D K profiles obtained from multi-level slug tests (inversion improves with priors for aquifer K, wellbore skin, and local presence of roots) show variable correlation with porosity and bring into question a Kozeny-Carman-type relation for much of the system. Modeling of 2D conservative tracer transport through a synthetic BHRS-like heterogeneous system shows the importance of including porosity heterogeneity (rather than assuming constant porosity for an aquifer) in addition to K heterogeneity. Similarly, 3D transient modeling of a conservative tracer test at the BHRS improves significantly with the use of prior geophysical information for layering and parameter structure and with use of both variable porosity and K. Joint inversion of multiple intersecting 2D radar tomograms gives well-resolved and consistent 3D distributions of porosity and unit boundaries that are largely correlated with neutron-porosity log and other site data, but the classic porosity-dielectric relation does not hold for one stratigraphic unit that also is recognized as anomalous with capacitive resistivity logs (i.e., cannot assume one petrophysical relation holds through a given aquifer system). Advances are being made in the new method of hydraulic tomography (2D with coincident electrical geophysics; 3D will be supplemented with priors); caveats here include the importance of boundary conditions and even ET effects. Also integrated data collection and modeling with multiple geophysical and hydrologic methods show promise for high-resolution quantification of vadose zone moisture and parameter distributions to improve variably saturated process models.

Solar-geophysical data number 499, March 1986, supplement

NASA Technical Reports Server (NTRS)

1986-01-01

This supplement contains the description and explanation of the data in the monthly publication Solar-Geophysical Data, compiled by the National Geophysical Data Center (NGDC) in Boulder, Colo., USA. Solar-Geophysical Data is intended to keep research workers informed on a timely schedule of the major events of solar activity and the associated interplanetary, ionospheric, radio propagation and other geophysical effects.

Detection of zone of seepage beneath earthfill dam

DOT National Transportation Integrated Search

2008-02-01

MST proposes to acquire resistivity and self-potential data at the Lake Sherwood earth fill dam site. These geophysical data will be processed, analyzed and interpreted with the objective of locating and mapping seepage pathways that might compromise...

Earth Observing System. Volume 1, Part 2: Science and Mission Requirements. Working Group Report Appendix

NASA Technical Reports Server (NTRS)

1984-01-01

Areas of global hydrologic cycles, global biogeochemical cycles geophysical processes are addressed including biological oceanography, inland aquatic resources, land biology, tropospheric chemistry, oceanic transport, polar glaciology, sea ice and atmospheric chemistry.

Louisville Southern Indiana Ohio River bridges project, Kentucky east end approach tunnel.

DOT National Transportation Integrated Search

2010-07-01

Missouri S&T proposes to acquire electrical resistivity and refraction tomography at the KDOT tunnel site, Louisville, Kentucky. These geophysical data will be processed, analyzed and interpreted with the objective of mapping and characterizing soil ...

An approach to understanding hydrologic connectivity on the hillslope and the implications for nutrient transport

USGS Publications Warehouse

Stieglitz, M.; Shaman, J.; McNamara, J.; Engel, V.; Shanley, J.; Kling, G.W.

2003-01-01

Hydrologic processes control much of the export of organic matter and nutrients from the land surface. It is the variability of these hydrologic processes that produces variable patterns of nutrient transport in both space and time. In this paper, we explore how hydrologic "connectivity" potentially affects nutrient transport. Hydrologic connectivity is defined as the condition by which disparate regions on the hillslope are linked via subsurface water flow. We present simulations that suggest that for much of the year, water draining through a catchment is spatially isolated. Only rarely, during storm and snowmelt events when antecedent soil moisture is high, do our simulations suggest that mid-slope saturation (or near saturation) occurs and that a catchment connects from ridge to valley. Observations during snowmelt at a small headwater catchment in Idaho are consistent with these model simulations. During early season discharge episodes, in which the mid-slope soil column is not saturated, the electrical conductivity in the stream remains low, reflecting a restricted, local (lower slope) source of stream water and the continued isolation of upper and mid-slope soil water and nutrients from the stream system. Increased streamflow and higher stream water electrical conductivity, presumably reflecting the release of water from the upper reaches of the catchment, are simultaneously observed when the mid-slope becomes sufficiently wet. This study provides preliminary evidence that the seasonal timing of hydrologic connectivity may affect a range of ecological processes, including downslope nutrient transport, C/N cycling, and biological productivity along the toposequence. A better elucidation of hydrologic connectivity will be necessary for understanding local processes as well as material export from land to water at regional and global scales. Copyright 2003 by the American Geophysical Union.

National Geological and Geophysical Data Preservation Program: Successes and Lessons Learned

NASA Astrophysics Data System (ADS)

Adrian, B. M.

2014-12-01

The United States Geological Survey (USGS) is widely recognized in the earth science community as possessing extensive collections of geologic and geophysical materials gathered by its research personnel. Since the USGS was established in 1879, hundreds of thousands of samples have been gathered in collections that range from localized, geographically-based assemblages to ones that are national or international in scope. These materials include, but are not limited to, rock and mineral specimens; fossils; drill cores and cuttings; geochemical standards; and soil, sediment, and geochemical samples. The USGS National Geological and Geophysical Data Preservation Program (NGGDPP) was established with the passage of the Energy Policy Act of 2005. Since its implementation, the USGS NGGDPP has taken an active role in providing opportunities to inventory, archive and preserve geologic and geophysical samples, and to make these samples and ancillary data discoverable on the Internet. Preserving endangered geoscience collections is more cost effective than recollecting this information. Preserving these collections, however, is only one part of the process - there also needs to be a means to facilitate open discovery and access to the physical objects and the ancillary digital records. The NGGDPP has celebrated successes such as the development of the USGS Geologic Collections Management System (GCMS), a master catalog and collections management plan, and the implementation and advancement of the National Digital Catalog, a digital inventory and catalog of geological and geophysical data and collections held by the USGS and State geological surveys. Over this period of time there has been many lessons learned. With the successes and lessons learned, NGGDPP is poised to take on challenges the future may bring.

The Legacy of Benoit Mandelbrot in Geophysics

NASA Astrophysics Data System (ADS)

Turcotte, D. L.

2001-12-01

The concept of fractals (fractional dimension) was introduced by Benoit Mandelbrot in his famous 1967 Science paper. The initial application was to the length of the coastline of Britain. A milestone in the appreciation of the fractal concept by geophysicists was the Union session of the AGU on fractals led off by Benoit in 1986. Although fractals have found important applications in almost every branch of the physical, biological, and social sciences, fractals have been particularly useful in geophysics. Drainage networks are fractal. The frequency-magnitude distribution of earthquakes is fractal. The scale invariance of landscapes and many other geological processes is due to the applicability of power-law (fractal) distributions. Clouds are often fractal. Porosity distributions are fractal. In an almost independent line of research, Benoit in collaboration with James Wallace and others developed the concept of self-affine fractals. The original applications were primarily to time series in hydrology and built on the foundation laid by Henry Hurst. Fractional Gaussian noises and fractional Brownian motions are ubiquitous in geophysics. These are expressed in terms of the power-law relation between the power-spectral density S and frequency f, S ~ f{ β }, examples are β = 0 (white noise), β = 1 (1/f noise), β = 2 (Brownian motion). Of particular importance in geophysics are fractional noises with β = 0.5, these are stationary but have long-range persistent and have a Hurst exponent H = 0.7. Examples include river flows, tree rings, sunspots, varves, etc. Two of Benoit Mandelbrot's major contributions in geophysics as in other fields are: (1) an appreciation of the importance of fat-tail, power-law (fractal) distributions and (2) an appreciation of the importance of self-similar long-range persistence in both stationary time series (noises) and nonstationary time series (walks).

Geophysical monitoring of organic contaminants in sediments

NASA Astrophysics Data System (ADS)

Zhang, C.; Jennings, J.

2016-12-01

Soil and groundwater contamination pose threats to the health of human and the environment. Successful contaminant remediation requires effective in situ monitoring of physical, chemical, and biological processes in the subsurface. Minimally invasive geophysical methods have shown promise in characterizing organic contaminants in soil and groundwater and have been applied to monitor remediation processes. This study examines the sensitivity of low field proton nuclear magnetic resonance (NMR) and complex conductivity to the presence of organic contaminants in sediments. We aim to improve understanding of relationships between NMR and complex conductivity observables and hydrological properties of the sediments, as well as the amount and state of contaminants in porous media. We used toluene as a representative organic contaminant, and pure silica sands and montmorillonite clay as synthetic sediments. Sand-clay mixtures with various sand/clay ratios were prepared and saturated with different concentration of toluene. Relationships between the compositions of porous media, hydrocarbon concentration, and hydrological properties of sediments and geophysical response were investigated. The results from NMR relaxation time (T2) measurements reveal the dominant control of clay content on T2 relaxation, establish minimum toluene detectability, and demonstrate the effect of contaminant concentration on NMR signals. The diffusion-relaxation (D-T2) correlation measurement show toluene can be resolved from toluene-water mixture in sand-clay mixture. The results from ongoing complex conductivity measurements will also be presented and discussed.

Geosoft eXecutables (GX's) Developed by the U.S. Geological Survey, Version 2.0, with Notes on GX Development from Fortran Code

USGS Publications Warehouse

Phillips, Jeffrey D.

2007-01-01

Introduction Geosoft executables (GX's) are custom software modules for use with the Geosoft Oasis montaj geophysical data processing system, which currently runs under the Microsoft Windows 2000 or XP operating systems. The U.S. Geological Survey (USGS) uses Oasis montaj primarily for the processing and display of airborne geophysical data. The ability to add custom software modules to the Oasis montaj system is a feature employed by the USGS in order to take advantage of the large number of geophysical algorithms developed by the USGS during the past half century. This main part of this report, along with Appendix 1, describes Version 2.0 GX's developed by the USGS or specifically for the USGS by contractors. These GX's perform both basic and advanced operations. Version 1.0 GX's developed by the USGS were described by Phillips and others (2003), and are included in Version 2.0. Appendix 1 contains the help files for the individual GX's. Appendix 2 describes the new method that was used to create the compiled GX files, starting from legacy Fortran source code. Although the new method shares many steps with the approach presented in the Geosoft GX Developer manual, it differs from that approach in that it uses free, open-source Fortran and C compilers and avoids all Fortran-to-C conversion.

The University of Texas Institute for Geophysics Marine Geology and Geophysics Field Course

NASA Astrophysics Data System (ADS)

Davis, M. B.; Gulick, S. P.; Allison, M. A.; Goff, J. A.; Duncan, D. D.; Saustrup, S.

2010-12-01

During the spring-summer intersession, we annually offer an intensive three-week field course designed to provide hands-on instruction and training for graduate and upper-level undergraduate students in the acquisition, processing, interpretation, and visualization of marine geological and geophysical data. Now in year four, the course covers high-resolution air gun and streamer seismic reflection, CHIRP sub-bottom profiling, multibeam bathymetry, sidescan sonar, several types of sediment coring, grab sampling, and the sedimentology of resulting seabed samples (e.g., core description, grain size analysis, x-radiography, etc.). Students first participate in three days of classroom instruction designed to provide theoretical and technical background on each field method and impart geologic context of the study area. Students then travel to the Gulf Coast for a week of at-sea field work. In the field, students rotate between two small research vessels: one vessel, the 22’ aluminum-hulled R/V Lake Itasca, owned and operated by UTIG, is used for multibeam bathymetry, sidescan sonar, and sediment sampling; the other, NOAA’s R/V Manta or the R/V Acadiana, operated by the Louisiana Universities Marine Consortium, is used for high-resolution seismic reflection, CHIRP sub-bottom profiling, gravity coring, and vibracoring. Students assist with survey design, learn systems setup and acquisition parameters, and safe instrument deployment and retrieval techniques. Students also perform on-shore sedimentology lab work, data quality control, data processing and visualization using industry-standard software such as Focus, Landmark, Caris, and Fledermaus. During the course’s final week, students return to the classroom where, collaborating in teams of three, they integrate and interpret data in a final project which examines the geologic history and/or sedimentary processes as typified by the Gulf Coast continental shelf. The course culminates in a series of professional-level final presentations and discussions. Following the course, students report a greater understanding of marine geology and geophysics via the course’s intensive, hands-on, team approach, and low instructor to student ratio. This course satisfies field experience requirements for some degree programs and thus provides a unique alternative to land-based field courses.

EDITORIAL: Fracture: from the atomic to the geophysical scale Fracture: from the atomic to the geophysical scale

NASA Astrophysics Data System (ADS)

Bouchaud, Elisabeth; Soukiassian, Patrick

2009-11-01

Although fracture is a very common experience in every day life, it still harbours many unanswered questions. New avenues of investigation arise concerning the basic mechanisms leading to deformation and failure in heterogeneous materials, particularly in non-metals. The processes involved are even more complex when plasticity, thermal fluctuations or chemical interactions between the material and its environment introduce a specific time scale. Sub-critical failure, which may be reached at unexpectedly low loads, is particularly important for silicate glasses. Another source of complications originates from dynamic fracture, when loading rates become so high that the acoustic waves produced by the crack interact with the material heterogeneities, in turn producing new waves that modify the propagation. Recent progress in experimental techniques, allowing one to test and probe materials at sufficiently small length or time scales or in three dimensions, has led to a quantitative understanding of the physical processes involved. In parallel, simulations have also progressed, by extending the time and length scales they are able to reach, and thus attaining experimentally accessible conditions. However, one central question remains the inclusion of these basic mechanisms into a statistical description. This is not an easy task, mostly because of the strong stress gradients present at the tip of a crack, and because the averaging of fracture properties over a heterogeneous material, containing more or less brittle phases, requires rare event statistics. Substantial progress has been made in models and simulations based on accurate experiments. From these models, scaling laws have been derived, linking the behaviour at a micro- or even nano-scale to the macroscopic and even to geophysical scales. The reviews in this Cluster Issue of Journal of Physics D: Applied Physics cover several of these important topics, including the physical processes in fracture mechanisms, the sub-critical failure issue, the dynamical fracture propagation, and the scaling laws from the micro- to the geophysical scales. Achievements and progress are reported, and the many open questions are discussed, which should provide a sound basis for present and future prospects.

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.

Improving the quality of marine geophysical track line data: Along-track analysis

NASA Astrophysics Data System (ADS)

Chandler, Michael T.; Wessel, Paul

2008-02-01

We have examined 4918 track line geophysics cruises archived at the U.S. National Geophysical Data Center (NGDC) using comprehensive error checking methods. Each cruise was checked for observation outliers, excessive gradients, metadata consistency, and general agreement with satellite altimetry-derived gravity and predicted bathymetry grids. Thresholds for error checking were determined empirically through inspection of histograms for all geophysical values, gradients, and differences with gridded data sampled along ship tracks. Robust regression was used to detect systematic scale and offset errors found by comparing ship bathymetry and free-air anomalies to the corresponding values from global grids. We found many recurring error types in the NGDC archive, including poor navigation, inappropriately scaled or offset data, excessive gradients, and extended offsets in depth and gravity when compared to global grids. While ˜5-10% of bathymetry and free-air gravity records fail our conservative tests, residual magnetic errors may exceed twice this proportion. These errors hinder the effective use of the data and may lead to mistakes in interpretation. To enable the removal of gross errors without over-writing original cruise data, we developed an errata system that concisely reports all errors encountered in a cruise. With such errata files, scientists may share cruise corrections, thereby preventing redundant processing. We have implemented these quality control methods in the modified MGD77 supplement to the Generic Mapping Tools software suite.

Recognition of Earthquake-Induced Damage in the Abakainon Necropolis (NE Sicily): Results From Geomorphological, Geophysical and Numerical Analyses

NASA Astrophysics Data System (ADS)

Bottari, C.; Albano, M.; Capizzi, P.; D'Alessandro, A.; Doumaz, F.; Martorana, R.; Moro, M.; Saroli, M.

2018-01-01

Seismotectonic activity and slope instability are a permanent threat in the archaeological site of Abakainon and in the nearby village of Tripi in NE Sicily. In recent times, signs of an ancient earthquake have been identified in the necropolis of Abakainon which dating was ascertained to the first century AD earthquake. The site is located on a slope of Peloritani Mts. along the Tindari Fault Line and contains evidence for earthquake-induced landslide, including fallen columns and blocks, horizontal shift and counter slope tilting of the tomb basements. In this paper, we used an integrated geomorphological and geophysical analysis to constrain the landslide. The research was directed to the acquisition of deep geological data for the reconstruction of slope process and the thickness of mobilized materials. The applied geophysical techniques included seismic refraction tomography and electrical resistivity tomography. The surveys were performed to delineate the sliding surface and to assess approximately the thickness of mobilized materials. The geophysical and geomorphologic data confirmed the presence of different overlapped landslides in the studied area. Moreover, a numerical simulation of the slope under seismic loads supports the hypothesis of a mobilization of the landslide mass in case of strong earthquakes (PGA > 0.3 g). However, numerical results highlight that the main cause of destruction for the Abakainon necropolis is the amplification of the seismic waves, occasionally accompanied by surficial sliding.

Large-scale climatic and geophysical controls on the leaf economics spectrum.

PubMed

Asner, Gregory P; Knapp, David E; Anderson, Christopher B; Martin, Roberta E; Vaughn, Nicholas

2016-07-12

Leaf economics spectrum (LES) theory suggests a universal trade-off between resource acquisition and storage strategies in plants, expressed in relationships between foliar nitrogen (N) and phosphorus (P), leaf mass per area (LMA), and photosynthesis. However, how environmental conditions mediate LES trait interrelationships, particularly at large biospheric scales, remains unknown because of a lack of spatially explicit data, which ultimately limits our understanding of ecosystem processes, such as primary productivity and biogeochemical cycles. We used airborne imaging spectroscopy and geospatial modeling to generate, to our knowledge, the first biospheric maps of LES traits, here centered on 76 million ha of Andean and Amazonian forest, to assess climatic and geophysical determinants of LES traits and their interrelationships. Elevation and substrate were codominant drivers of leaf trait distributions. Multiple additional climatic and geophysical factors were secondary determinants of plant traits. Anticorrelations between N and LMA followed general LES theory, but topo-edaphic conditions strongly mediated and, at times, eliminated this classic relationship. We found no evidence for simple P-LMA or N-P trade-offs in forest canopies; rather, we mapped a continuum of N-P-LMA interactions that are sensitive to elevation and temperature. Our results reveal nested climatic and geophysical filtering of LES traits and their interrelationships, with important implications for predictions of forest productivity and acclimation to rapid climate change.

Multi-method characterization of a landslide in Champagne vineyards: the case study of the Jacotines landslide (Marne, France)

NASA Astrophysics Data System (ADS)

Nicolas, Bollot; Guillaume, Pierre; Gilles, Grandjean

2014-05-01

Key words : landslide, Champagne vineyards , geomorphology, geophysical data, superficial structure The Champagne region is strongly impacted by landslides. Usually inactive, these landslides suffer from partial reactivations leading to important damages, especially when they occur in the vineyards. In the Marne valley, and particularly in the center of Champagne vineyards area (Reuil), the Jacotines site is representative of such landslides since it presents typical surface characteristics widely observed in the region. However, its size, and especially its internal structure, can't be deduced from the surface analysis only. The aim of this work is to combine surface patterns analysis, geophysical data and borehole data to produce an interpretative model of the landslide. Preliminary geomorphological cartography was used for determining the influence of the landslide. From this information, geophysical investigations were carried out to image the internal structure of the landslide. Geophysical data fusion (combination of seismic and geoelectrical tomograms) was used to estimate the mechanical behavior and the fissuring pattern of the slope. Three transverse and longitudinal tomograms were used to define an heterogeneous area between 20 and 50 meters depth and a weathered zone from 0 to 10-20 meters depth. A 60 meters depth borehole on the main transverse tomogram found the shear plane and clarified the structure of the heterogeneous area as well as the uppermost weathered layer composed by debris flows resulting from partial reactivations processes.

The Electrical Self-Potential Method as a Non-Intrusive Snow-Hydrological Sensor

NASA Astrophysics Data System (ADS)

Kulessa, B.; Thompson, S. S.; Luethi, M. P.; Essery, R.

2015-12-01

Building on growing momentum in the application of geophysical techniques to snow problems and, specifically, on new theory and an electrical geophysical snow hydrological model published recently; we demonstrate for the first time that the electrical self-potential geophysical technique can sense in-situ bulk meltwater fluxes. This has broad and immediate implications for snow measurement practice, modelling and operational snow forecasting. Our ability to measure, quantify and assimilate hydrological properties and processes of snow in operational models is disproportionally poor compared to the significance of seasonal snowmelt as a global water resource and major risk factor in flood and avalanche forecasting. Encouraged by recent theoretical, modelling and laboratory work, we show here that the diurnal evolution of aerially-distributed self-potential magnitudes closely track those of bulk meltwater fluxes in melting in-situ snowpacks at Rhone and Jungfraujoch glaciers, Switzerland. Numerical modelling infers temporally-evolving liquid water contents in the snowpacks on successive days in close agreement with snow-pit measurements. Muting previous concerns, the governing physical and chemical properties of snow and meltwater became temporally invariant for modelling purposes. Because measurement procedure is straightforward and readily automated for continuous monitoring over significant spatial scales, we conclude that the self-potential geophysical method is a highly-promising non-intrusive snow-hydrological sensor for measurement practice, modelling and operational snow forecasting.

Multivariate spatio-temporal modelling for assessing Antarctica's present-day contribution to sea-level rise

PubMed Central

Zammit-Mangion, Andrew; Rougier, Jonathan; Schön, Nana; Lindgren, Finn; Bamber, Jonathan

2015-01-01

Antarctica is the world's largest fresh-water reservoir, with the potential to raise sea levels by about 60 m. An ice sheet contributes to sea-level rise (SLR) when its rate of ice discharge and/or surface melting exceeds accumulation through snowfall. Constraining the contribution of the ice sheets to present-day SLR is vital both for coastal development and planning, and climate projections. Information on various ice sheet processes is available from several remote sensing data sets, as well as in situ data such as global positioning system data. These data have differing coverage, spatial support, temporal sampling and sensing characteristics, and thus, it is advantageous to combine them all in a single framework for estimation of the SLR contribution and the assessment of processes controlling mass exchange with the ocean. In this paper, we predict the rate of height change due to salient geophysical processes in Antarctica and use these to provide estimates of SLR contribution with associated uncertainties. We employ a multivariate spatio-temporal model, approximated as a Gaussian Markov random field, to take advantage of differing spatio-temporal properties of the processes to separate the causes of the observed change. The process parameters are estimated from geophysical models, while the remaining parameters are estimated using a Markov chain Monte Carlo scheme, designed to operate in a high-performance computing environment across multiple nodes. We validate our methods against a separate data set and compare the results to those from studies that invariably employ numerical model outputs directly. We conclude that it is possible, and insightful, to assess Antarctica's contribution without explicit use of numerical models. Further, the results obtained here can be used to test the geophysical numerical models for which in situ data are hard to obtain. © 2015 The Authors. Environmetrics published by John Wiley & Sons Ltd. PMID:25937792

Crisp clustering of airborne geophysical data from the Alto Ligonha pegmatite field, northeastern Mozambique, to predict zones of increased rare earth element potential

NASA Astrophysics Data System (ADS)

Eberle, Detlef G.; Daudi, Elias X. F.; Muiuane, Elônio A.; Nyabeze, Peter; Pontavida, Alfredo M.

2012-01-01

The National Geology Directorate of Mozambique (DNG) and Maputo-based Eduardo-Mondlane University (UEM) entered a joint venture with the South African Council for Geoscience (CGS) to conduct a case study over the meso-Proterozoic Alto Ligonha pegmatite field in the Zambézia Province of northeastern Mozambique to support the local exploration and mining sectors. Rare-metal minerals, i.e. tantalum and niobium, as well as rare-earth minerals have been mined in the Alto Ligonha pegmatite field since decades, but due to the civil war (1977-1992) production nearly ceased. The Government now strives to promote mining in the region as contribution to poverty alleviation. This study was undertaken to facilitate the extraction of geological information from the high resolution airborne magnetic and radiometric data sets recently acquired through a World Bank funded survey and mapping project. The aim was to generate a value-added map from the airborne geophysical data that is easier to read and use by the exploration and mining industries than mere airborne geophysical grid data or maps. As a first step towards clustering, thorium (Th) and potassium (K) concentrations were determined from the airborne geophysical data as well as apparent magnetic susceptibility and first vertical magnetic gradient data. These four datasets were projected onto a 100 m spaced regular grid to assemble 850,000 four-element (multivariate) sample vectors over the study area. Classification of the sample vectors using crisp clustering based upon the Euclidian distance between sample and class centre provided a (pseudo-) geology map or value-added map, respectively, displaying the spatial distribution of six different classes in the study area. To learn the quality of sample allocation, the degree of membership of each sample vector was determined using a-posterior discriminant analysis. Geophysical ground truth control was essential to allocate geology/geophysical attributes to the six classes. The highest probability to meet pegmatite bodies is in close vicinity to (magnetic) amphibole schist occurring in areas where depletion of potassium as indication of metasomatic processes is evident from the airborne radiometric data. Clustering has proven to be a fast and effective method to compile value-added maps from multivariate geophysical datasets. Experience made in the Alto Ligonha pegmatite field encourages adopting this new methodology for mapping other parts of the Mozambique Fold Belt.

Geophysical investigations of well fields to characterize fractured-bedrock aquifers in southern New Hampshire

USGS Publications Warehouse

Degnan, James R.; Moore, Richard Bridge; Mack, Thomas J.

2001-01-01

Bedrock-fracture zones near high-yield bedrock wells in southern New Hampshire well fields were located and characterized using seven surface and six borehole geophysical survey methods. Detailed surveys of six sites with various methods provide an opportunity to integrate and compare survey results. Borehole geophysical surveys were conducted at three of the sites to confirm subsurface features. Hydrogeologic settings, including a variety of bedrock and surface geologic materials, were sought to gain an insight into the usefulness of the methods in varied terrains. Results from 15 survey lines, 8 arrays, and 3 boreholes were processed and interpreted from the 6 sites. The surface geophysical methods used provided physical properties of fractured bedrock. Seismic refraction and ground-penetrating radar (GPR) primarily were used to characterize the overburden materials, but in a few cases indicated bedrock-fracture zones. Magnetometer surveys were used to obtain background information about the bedrock to compare with other results, and to search for magnetic lows, which may result from weathered fractured rock. Electromagnetic terrain conductivity surveys (EM) and very-low-frequency electromagnetic surveys (VLF) were used as rapid reconnaissance techniques with the primary purpose of identifying electrical anomalies, indicating potential fracture zones in bedrock. Direct-current (dc) resistivity methods were used to gather detailed subsurface information about fracture depth and orientation. Two-dimensional (2-D) dc-resistivity surveys using dipole-dipole and Schlumberger arrays located and characterized the overburden, bedrock, and bedrock-fracture zones through analysis of data inversions. Azimuthal square array dc-resistivity survey results indicated orientations of conductive steep-dipping bedrock-fracture zones that were located and characterized by previously applied geophysical methods. Various available data sets were used for site selection, characterizations, and interpretations. Lineament data, developed as a part of a statewide and regional scale investigation of the bedrock aquifer, were available to identify potential near-vertical fracture zones. Geophysical surveys indicated fracture zones coincident with lineaments at 4 of the sites. Geologic data collected as a part of the regional scale investigation provided outcrop fracture measurements, ductile fabric, and contact information. Dominant fracture trends correspond to the trends of geophysical anomalies at 4 of the sites. Water-well drillers? logs from water supply and environmental data sets also were used where available to characterize sites. Regional overburden information was compiled from stratified-drift aquifer maps and surficial-geological maps.

Quaternary sediment architecture in the Orkhon Valley (central Mongolia) inferred from capacitive coupled resistivity and Georadar measurements

NASA Astrophysics Data System (ADS)

Mackens, Sonja; Klitzsch, Norbert; Grützner, Christoph; Klinger, Riccardo

2017-09-01

Detailed information on shallow sediment distribution in basins is required to achieve solutions for problems in Quaternary geology, geomorphology, neotectonics, (geo)archaeology, and climatology. Usually, detailed information is obtained by studying outcrops and shallow drillings. Unfortunately, such data are often sparsely distributed and thus cannot characterise entire basins in detail. Therefore, they are frequently combined with remote sensing methods to overcome this limitation. Remote sensing can cover entire basins but provides information of the land surface only. Geophysical methods can close the gap between detailed sequences of the shallow sediment inventory from drillings at a few spots and continuous surface information from remote sensing. However, their interpretation in terms of sediment types is often challenging, especially if permafrost conditions complicate their interpretation. Here we present an approach for the joint interpretation of the geophysical methods ground penetrating radar (GPR) and capacitive coupled resistivity (CCR), drill core, and remote sensing data. The methods GPR and CCR were chosen because they allow relatively fast surveying and provide complementary information. We apply the approach to the middle Orkhon Valley in central Mongolia where fluvial, alluvial, and aeolian processes led to complex sediment architecture. The GPR and CCR data, measured on profiles with a total length of about 60 km, indicate the presence of two distinct layers over the complete surveying area: (i) a thawed layer at the surface, and (ii) a frozen layer below. In a first interpretation step, we establish a geophysical classification by considering the geophysical signatures of both layers. We use sedimentological information from core logs to relate the geophysical classes to sediment types. This analysis reveals internal structures of Orkhon River sediments, such as channels and floodplain sediments. We also distinguish alluvial fan deposits and aeolian sediments by their distinct geophysical signature. With this procedure we map aeolian sediments, debris flow sediments, floodplains, and channel sediments along the measured profiles in the entire basin. We show that the joint interpretation of drillings and geophysical profile measurements matches the information from remote sensing data, i.e., the sediment architecture of vast areas can be characterised by combining these techniques. The method presented here proves powerful for characterising large areas with minimal effort and can be applied to similar settings.

Handbook of Agricultural Geophysics

USDA-ARS?s Scientific Manuscript database

Geophysical methods continue to show great promise for use in agriculture. The term “agricultural geophysics” denotes a subdiscipline of geophysics that is focused only on agricultural applications. The Handbook of Agricultural Geophysics was compiled to include a comprehensive overview of the geoph...

Airborne electromagnetic and magnetic geophysical survey data of the Yukon Flats and Fort Wainwright areas, central Alaska, June 2010

USGS Publications Warehouse

Ball, Lyndsay B.; Smith, Bruce D.; Minsley, Burke J.; Abraham, Jared D.; Voss, Clifford I.; Astley, Beth N.; Deszcz-Pan, Maria; Cannia, James C.

2011-01-01

In June 2010, the U.S. Geological Survey conducted airborne electromagnetic and magnetic surveys of the Yukon Flats and Fort Wainwright study areas in central Alaska. These data were collected to estimate the three-dimensional distribution of permafrost at the time of the survey. These data were also collected to evaluate the effectiveness of these geophysical methods at mapping permafrost geometry and to better define the physical properties of the subsurface in discontinuous permafrost areas. This report releases digital data associated with these surveys. Inverted resistivity depth sections are also provided in this data release, and data processing and inversion methods are discussed.

Geophysics and nutritional science: toward a novel, unified paradigm.

PubMed

Eshel, Gidon; Martin, Pamela A

2009-05-01

This article discusses a few basic geophysical processes, which collectively indicate that several nutritionally adverse elements of current Western diets also yield environmentally harmful food consumption patterns. We address oceanic dead zones, which are at the confluence of oceanography, aquatic chemistry, and agronomy and which are a clear environmental problem, and agriculture's effects on the surface heat budget. These exemplify the unknown, complex, and sometimes unexpected large-scale environmental effects of agriculture. We delineate the significant alignment in purpose between nutritional and environmental sciences. We identify red meat, and to a lesser extent the broader animal-based portion of the diet, as having the greatest environmental effect, with clear nutritional parallels.

USGS advances in integrated, high-resolution sea-floor mapping: inner continental shelf to estuaries

USGS Publications Warehouse

Denny, J.F.; Schwab, W.C.; Twichell, D.C.; O'Brien, T.F.; Danforth, W.W.; Foster, D.S.; Bergeron, E.; Worley, C.W.; Irwin, B.J.; Butman, B.; Valentine, P.C.; Baldwin, W.E.; Morton, R.A.; Thieler, E.R.; Nichols, D.R.; Andrews, B.D.

2007-01-01

The U.S. Geological Survey (USGS) has been involved in geological mapping of the sea floor for the past thirty years. Early geophysical and acoustic mapping efforts using GLORIA (Geologic LOng Range Inclined ASDIC) a long-range sidescan-sonar system, provided broad-scale imagery of deep waters within the U.S. Exclusive Economic Zone (EEZ). In the early 1990's, research emphasis shifted from deep- to shallow-water environments to address pertinent coastal research and resource management issues. Use of shallow-water, high-resolution geophysical systems has enhanced our understanding of the processes shaping shallow marine environments. However, research within these shallow-water environments continues to present technological challenges.

USAF/SCEEE Summer Faculty Research Program (1982). Management Report.

DTIC Science & Technology

1982-10-01

Patrick J. Sweeney, Ph.D., P.E. Mary Doddy, M.S. ABSTRACT This dynamic simulation computer model demonstrates the affects of C-forces upon the eyeball...Assistant Professor Specialty: Numerical Modeling and University of Lowell Computer Simulation of Mathematics Department Geophysical Problems Lowell...Problems And Promises 25 Modeling And Tracking Saccadic Dr. John D. Enderle Eye Movements 26 Dynamic Response Of Doubly Curved Dr. Fernando E. Fagundo

AGU Scholars

NASA Astrophysics Data System (ADS)

In recognition of the strong support and substantial contribution given by the American Geophysical Union to the American Geological Institute's Minority Participation Program, 16 of the 1982-83 scholarship recipients were designated ‘AGU Scholars.’ Because of a matching grant from the National Oceanographic and Atmospheric Administration to increase the number of minority students studying in fields related to the development of marine and coastal resources, five of this group were designated ‘AGU Sea Grant Scholars.’ The AGU Scholars, all of whom are following courses of study related to AGU's broad areas of interest, are Torin J. Edwards, a student of geophysics at the University of New Orleans; Gwendolyn Hofler, geophysics, Virginia State University; Jolecia Mitchell, environmental sciences, Howard University; Louis F. Montiel, geohydrology, Northern Arizona University; Alex M. Richards, geophysics, Northern Arizona University; Roxanne C. Rogers, geophysics, Colorado School of Mines; John F. Vargas, geophysics, University of Kansas; Toni M. VanDam, geophysics, University of Colorado; Edith G. Williams, geophysics, Stanford University; Saundra F. Willis, geosciences, California State University, Northridge; and Lacy B. Ward, geophysics, Virginia State University.

Carbone_et_al_2016_ambient_data

EPA Pesticide Factsheets

This data set has two sets of gaseous elemental mercury data. The first column contains all Hg related data some of which may have been affected by the upslope events such as the emissions from the nearby volcano. The next column contain values that were flagged and excluded as being affected by the nearby volcanic events. The flagging method used to eliminate these values was developed using an episode identification scheme using SO2 data. For the years of 2002 through 2004, hourly SO2 data were used to llag the upslope values. For the years of 2005-2009, 5 minute SO2 values were used to flag upslope events.While SO2 and O3 data were collected by EPA as part of this study, the CO2 data were downloaded from NOAA data website along with the flag related information provided below. (http://www.esrl.noaa.gov/gmd/dv/data/index.php?parameter_name=Carbon%2BDioxide&showall=1&site=MLO)This dataset is associated with the following publication:Carbone, F., M. Landis, C.N. Gencarelli, A. Naccarato, F. Sprovieri, F. De Simone, I.M. Hedgecock, and N. Pirrone. Sea surface temperature variation linked to elemental mercury concentrations measured on Mauna Loa. GEOPHYSICAL RESEARCH LETTERS. American Geophysical Union, Washington, DC, USA, online, (2016).

PRESS40: a project for involving students in active seismic risk mitigation

NASA Astrophysics Data System (ADS)

Barnaba, Carla; Contessi, Elisa; Rosa Girardi, Maria

2016-04-01

To memorialize the anniversary of the 1976 Friuli earthquake, the Istituto Statale di Istruzione Superiore "Magrini Marchetti" in Gemona del Friuli (NE Italy), with the collaboration of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), has promoted the PRESS40 Project (Prevenzione Sismica nella Scuola a 40 anni dal terremoto del Friuli, that in English sounds like "Seismic Prevention at School 40 years later the Friuli earthquake"). The project has developed in the 2015-2016 school year, starting from the 40th anniversary of the Friuli earthquake, and it aims to disseminate historical memory, seismic culture and awareness of seismic safety in the young generations, too often unconscious of past experiences, as recent seismic hazard perception tests have demonstrated. The basic idea of the PRESS40 Project is to involve the students in experimental activities to be active part of the seismic mitigation process. The Project is divided into two main parts, the first one in which students learn-receive knowledge from researchers, and the second one in which they teach-bring knowledge to younger students. In the first part of the project, 75 students of the "Magrini Marchetti" school acquired new geophysical data, covering the 23 municipalities from which they come from. These municipalities represent a wide area affected by the 1976 Friuli earthquake. In each locality a significant site was examined, represented by a school area. At least, 127 measurements of ambient noise have been acquired. Data processing and interpretation of all the results are still going on, under the supervision of OGS researchers.The second part of the project is planned for the early spring, when the students will present the results of geophysical survey to the younger ones of the monitored schools and to the citizens in occasion of events to commemorate the 40th anniversary of the Friuli earthquake.

Ninety Years of International Cooperation in Geophysics

NASA Astrophysics Data System (ADS)

Ismail-Zadeh, A.; Beer, T.

2009-05-01

Because applicable physical, chemical, and mathematical studies of the Earth system must be both interdisciplinary and international, the International Union of Geodesy and Geophysics (IUGG) was formed in 1919 as an non-governmental, non-profit organization dedicated to advancing, promoting, and communicating knowledge of the Earth system, its space environment, and the dynamical processes causing change. The Union brings together eight International Associations that address different disciplines of Earth sciences. Through these Associations, IUGG promotes and enables studies in the geosciences by providing a framework for collaborative research and information exchange, by organizing international scientific assemblies worldwide, and via research publications. Resolutions passed by assemblies of IUGG and its International Associations set geophysical standards and promote issues of science policy on which national members agree. IUGG has initiated and/or vigorously supported collaborative international efforts that have led to highly productive worldwide interdisciplinary research programs, such as the International Geophysical Year and subsequent International Years (IPY, IYPE, eGY, and IHY), International Lithosphere Programme, World Climate Research Programme, Geosphere-Biosphere Programme, and Integrated Research on Risk Disaster. IUGG is inherently involved in the projects and programs related to climate change, global warming, and related environmental impacts. One major contribution has been the creation, through the International Council for Science (ICSU), of the World Data Centers and the Federation of Astronomical and Geophysical Data Analysis Services. These are being transformed to the ICSU World Data System, from which the data gathered during the major programs and data products will be available to researchers everywhere. IUGG cooperates with UNESCO, WMO, and some other U.N. and non-governmental organizations in the study of natural catastrophes, climate dynamics, and in geodetic, hydrological, meteorological, oceanographic, seismological, and volcanological research. IUGG also places particular emphasis on the scientific problems of economically less-developed countries by sponsoring activities relevant to their scientific needs (e.g. Geosciences in Africa, Water Resources, Health and Well-Being etc.) The American Geophysical Union was established as the U.S. National Committee for IUGG in 1919 and today has become a distinguished union of individual geoscientists around the world. Several regional geoscience societies also evolved during the last several decades, most prominent being the European Geosciences Union and the Asia Oceania Geosciences Society. These, and some other national and regional geophysical societies, together with IUGG play a strong part in the international cooperation and promotion of geophysical sciences. At the same time the "geosciences" space is getting crowded, and there is a lot of overlap. International linkages between IUGG, AGU, EGU and other geophysical societies as well as their linkage with International Scientific Unions, that comprise the GeoUnions, are going to become more and more important. Working together is going to be more fruitful than territorial disputes. But what mechanisms can be used to encourage relationships between the international, national and regional geophysical and geoscientific bodies? We will discuss some possibilities on how to come together, to develop and to implement joint programs, research meeting, open forums, and policy statements.

Interpretation of electrical resistivity data acquired at the Aurora plant site

DOT National Transportation Integrated Search

2008-02-01

MST proposes to acquire high-resolution reflection seismic data at the Knight Hawk Coal Company construction site. These geophysical data will be processed, analyzed and interpreted with the objective of locating and mapping any subsurface voids that...

Assessment of karst activity at Springfield Route 60 study site

DOT National Transportation Integrated Search

2008-02-01

MST proposes to acquire electrical resistivity data within a roadway ROW. These geophysical data will be processed, analyzed and interpreted with the objective of locating and mapping any subsurface voids that might compromise the integrity of the pi...

Soil moisture sensing via swept frequency based microwave sensors

USDA-ARS?s Scientific Manuscript database

Accurate measurement of moisture content is a prime requirement in hydrological, geophysical, and biogeochemical research as well as for material characterization, process control, and irrigation efficiency in water limited regions. Within these areas, consideration of the surface area and associate...

Quantifying and Projecting Relative Sea-Level Rise At The Regional Scale: The Bangladesh Sea-Level Project (BanD-AID)

NASA Astrophysics Data System (ADS)

Shum, C. K.; Kuo, C. Y.; Guo, J.; Shang, K.; Tseng, K. H.; Wan, J.; Calmant, S.; Ballu, V.; Valty, P.; Kusche, J.; Hossain, F.; Khan, Z. H.; Rietbroek, R.; Uebbing, B.

2014-12-01

The potential for accelerated sea-level rise under anthropogenic warming is a significant societal problem, in particular in world's coastal deltaic regions where about half of the world's population resides. Quantifying geophysical sources of sea-level rise with the goal of improved projection at local scales remains a complex and challenging interdisciplinary research problem. These processes include ice-sheet/glacier ablations, steric sea-level, solid Earth uplift or subsidence due to GIA, tectonics, sediment loading or anthropogenic causes, hydrologic imbalance, and human processes including water retention in reservoirs and aquifer extraction. The 2013 IPCC AR5 concluded that the observed and explained geophysical causes of global geocentric sea-level rise, 1993-2010, is closer towards closure. However, the discrepancy reveals that circa 1.3→37.5% of the observed sea-level rise remains unexplained. This relatively large discrepancy is primarily attributable to the wide range of estimates of respective contributions of Greenland and Antarctic ice-sheets and mountain/peripheral glaciers to sea-level rise. Understanding and quantifying the natural and anthropogenic processes governing solid Earth (land, islands and sea-floor) uplift or subsidence at the regional and local scales remain elusive to enable addressing coastal vulnerability due to relative sea-level rise hazards, such as the Bangladesh Delta. This study focuses on addressing coastal vulnerability of Bangladesh, a Belmont Forum/IGFA project, BanD-AID (http://Belmont-SeaLevel.org). Sea-level rise, along with tectonic, sediment load and groundwater extraction induced land uplift/subsidence, have exacerbated Bangladesh's coastal vulnerability, affecting 150 million people in one of the world's most densely populated regions. Here we present preliminary results using space geodetic observations, including satellite radar and laser altimetry, GRACE gravity, tide gauge, hydrographic, and GPS/InSAR observed land subsidence, and via fingerprint sea-level adjustment and reconstructed sea-level approaches, for improved quantification of major contributions to, and the projection of relative sea-level rise at the Bangladesh delta, towards addressing its coastal vulnerability and sustainability.

Publications - IC 52 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey ; Aerial Photography; Aeromagnetic; Aeromagnetic Data; Aeromagnetic Survey; Airborne Geophysical Survey Resistivity Data; Apparent Resistivity Map; Apparent Resistivity Survey; Arctic Deposit; Arsenic; Arsenopyrite

Publications - IC 51 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey Photography; Aeromagnetic; Aeromagnetic Data; Aeromagnetic Survey; Airborne Geophysical Survey; Alaska Data; Apparent Resistivity Map; Apparent Resistivity Survey; Arctic Deposit; Arsenic; Arsenopyrite

Publications - SR 61 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey K) Keywords Admiralty Island; Aeromagnetic Data; Aeromagnetic Survey; Airborne Geophysical Survey Dome; Conductivity Survey; Construction Materials; Copper; Core Drilling; Council; Crushed Gravel

Agricultural geophysics: Past/present accomplishments and future advancements

USDA-ARS?s Scientific Manuscript database

Geophysical methods have become an increasingly valuable tool for application within a variety of agroecosystems. Agricultural geophysics measurements are obtained at a wide range of scales and often exhibit significant variability both temporally and spatially. The three geophysical methods predomi...

The physics of the earth's core: An introduction

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

Melchior, P.

1986-01-01

This book is a reference text providing information on physical topics of recent developments in internal geophysics. The text summarizes papers covering theoretical geophysics. Basic formulae, definitions and theorems are not explained in detail due to the limited space. The contents include applications to geodesy, geophysics, astronomy, astrophysics, geophysics and planetary physics. The formal contents include: The Earth's model; Thermodynamics; Hydrodynamics; Geomagnetism; Geophysical implications in the Earth's core.

Global status of and prospects for protection of terrestrial geophysical diversity.

PubMed

Sanderson, Eric W; Segan, Daniel B; Watson, James E M

2015-06-01

Conservation of representative facets of geophysical diversity may help conserve biological diversity as the climate changes. We conducted a global classification of terrestrial geophysical diversity and analyzed how land protection varies across geophysical diversity types. Geophysical diversity was classified in terms of soil type, elevation, and biogeographic realm and then compared to the global distribution of protected areas in 2012. We found that 300 (45%) of 672 broad geophysical diversity types currently meet the Convention on Biological Diversity's Aichi Target 11 of 17% terrestrial areal protection, which suggested that efforts to implement geophysical diversity conservation have a substantive basis on which to build. However, current protected areas were heavily biased toward high elevation and low fertility soils. We assessed 3 scenarios of protected area expansion and found that protection focused on threatened species, if fully implemented, would also protect an additional 29% of geophysical diversity types, ecoregional-focused protection would protect an additional 24%, and a combined scenario would protect an additional 42%. Future efforts need to specifically target low-elevation sites with productive soils for protection and manage for connectivity among geophysical diversity types. These efforts may be hampered by the sheer number of geophysical diversity facets that the world contains, which makes clear target setting and prioritization an important next step. © 2015 Society for Conservation Biology.

REVIEWS OF TOPICAL PROBLEMS: Free convection in geophysical processes

NASA Astrophysics Data System (ADS)

Alekseev, V. V.; Gusev, A. M.

1983-10-01

A highly significant geophysical process, free convection, is examined. Thermal convection often controls the dynamical behavior in several of the earth's envelopes: the atmosphere, ocean, and mantle. Section 2 sets forth the thermohydrodynamic equations that describe convection in a compressible or incompressible fluid, thermochemical convection, and convection in the presence of thermal diffusion. Section 3 reviews the mechanisms for the origin of the global atmospheric and oceanic circulation. Interlatitudinal convection and jet streams are discussed, as well as monsoon circulation and the mean meridional circulation of ocean waters due to the temperature and salinity gradients. Also described are the hypotheses for convective motion in the mantle and the thermal-wave (moving flame) mechanism for inducing global circulation (the atmospheres of Venus and Mars provide illustrations). Eddy formation by convection in a centrifugal force field is considered. Section 4 deals with medium- and small-scale convective processes, including hurricane systems with phase transitions, cellular cloud structure, and convection penetrating into the ocean, with its stepped vertical temperature and salinity microstructure. Self-oscillatory processes involving convection in fresh-water basins are discussed, including effects due to the anomalous (p,T) relation for water.

Publications - SR 60 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey ; Aeromagnetic Survey; Airborne Geophysical Survey; Alaska Highway Corridor; Alaska Peninsula; Alaska, State of ; Bismuth; Chalcopyrite; Chandalar Mining District; Cleary Summit; Coal; Conductivity Survey; Construction

Publications - IC 46 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey ; Aeromagnetic; Aeromagnetic Survey; Airborne Geophysical Survey; Antimony; Arsenic; Arsenopyrite; Base Metals ; Electromagnetic Data; Electromagnetic Survey; Exploration; Fairbanks Mining District; Fort Knox Mine; Fortymile

A fractured rock geophysical toolbox method selection tool

USGS Publications Warehouse

Day-Lewis, F. D.; Johnson, C.D.; Slater, L.D.; Robinson, J.L.; Williams, J.H.; Boyden, C.L.; Werkema, D.D.; Lane, J.W.

2016-01-01

Geophysical technologies have the potential to improve site characterization and monitoring in fractured rock, but the appropriate and effective application of geophysics at a particular site strongly depends on project goals (e.g., identifying discrete fractures) and site characteristics (e.g., lithology). No method works at every site or for every goal. New approaches are needed to identify a set of geophysical methods appropriate to specific project goals and site conditions while considering budget constraints. To this end, we present the Excel-based Fractured-Rock Geophysical Toolbox Method Selection Tool (FRGT-MST). We envision the FRGT-MST (1) equipping remediation professionals with a tool to understand what is likely to be realistic and cost-effective when contracting geophysical services, and (2) reducing applications of geophysics with unrealistic objectives or where methods are likely to fail.

Coulombic faulting from the grain scale to the geophysical scale: lessons from ice

NASA Astrophysics Data System (ADS)

Weiss, Jérôme; Schulson, Erland M.

2009-11-01

Coulombic faulting, a concept formulated more than two centuries ago, still remains pertinent in describing the brittle compressive failure of various materials, including rocks and ice. Many questions remain, however, about the physical processes underlying this macroscopic phenomenology. This paper reviews the progress made in these directions during the past few years through the study of ice and its mechanical behaviour in both the laboratory and the field. Fault triggering is associated with the formation of specific features called comb-cracks and involves frictional sliding at the micro(grain)-scale. Similar mechanisms are observed at geophysical scales within the sea ice cover. This scale-independent physics is expressed by the same Coulombic phenomenology from laboratory to geophysical scales, with a very similar internal friction coefficient (μ ≈ 0.8). On the other hand, the cohesion strongly decreases with increasing spatial scale, reflecting the role of stress concentrators on fault initiation. Strong similarities also exist between ice and other brittle materials such as rocks and minerals and between faulting of the sea ice cover and Earth's crust, arguing for the ubiquitous nature of the underlying physics.

High-resolution geophysical data collected aboard the U.S. Geological Survey research vessel Rafael to supplement existing datasets from Buzzards Bay and Vineyard Sound, Massachusetts

USGS Publications Warehouse

Pendleton, Elizabeth A.; Andrews, Brian D.; Danforth, William W.; Foster, David S.

2014-01-01

Geophysical and geospatial data were collected in Buzzards Bay, in the shallow-water areas of Vineyard Sound, and in the nearshore areas off the eastern Elizabeth Islands and northern coast of Martha's Vineyard, Massachusetts, on the U.S. Geological Survey research vessel Rafael between 2007 and 2011, in a collaborative effort between the U.S. Geological Survey and the Massachusetts Office of Coastal Zone Management. This report describes results of this collaborative effort, which include mapping the geology of the inner shelf zone of the Elizabeth Islands and the sand shoals of Vineyard Sound and studying geologic processes that contribute to the evolution of this area. Data collected during these surveys include: bathymetry, acoustic backscatter, seismic-reflection profiles, sound velocity profiles, and navigation. The long-term goals of this project are (1) to provide high-resolution geophysical data that will support research on the influence of sea-level change and sediment supply on coastal evolution and (2) to inventory subtidal marine habitats and their distribution within the coastal zone of Massachusetts.

Global ocean tides through assimilation of oceanographic and altimeter satellite data in a hydrodynamic model

NASA Technical Reports Server (NTRS)

Leprovost, Christian; Mazzega, P.; Vincent, P.

1991-01-01

Ocean tides must be considered in many scientific disciplines: astronomy, oceanography, geodesy, geophysics, meteorology, and space technologies. Progress in each of these disciplines leads to the need for greater knowledge and more precise predictions of the ocean tide contribution. This is particularly true of satellite altimetry. On one side, the present and future satellite altimetry missions provide and will supply new data that will contribute to the improvement of the present ocean tide solutions. On the other side, tidal corrections included in the Geophysical Data Records must be determined with the maximum possible accuracy. The valuable results obtained with satellite altimeter data thus far have not been penalized by the insufficiencies of the present ocean tide predictions included in the geophysical data records (GDR's) because the oceanic processes investigated have shorter wavelengths than the error field of the tidal predictions, so that the residual errors of the tidal corrections are absorbed in the empirical tilt and bias corrections of the satellite orbit. For future applications to large-scale oceanic phenomena, however, it will no longer be possible to ignore these insufficiencies.

How Collecting and Freely Sharing Geophysical Data Broadly Benefits Society

NASA Astrophysics Data System (ADS)

Frassetto, A.; Woodward, R.; Detrick, R. S.

2017-12-01

Valuable but often unintended observations of environmental and human-related processes have resulted from open sharing of multidisciplinary geophysical observations collected over the past 33 years. These data, intended to fuel fundamental academic research, are part of the Incorporated Research Institutions for Seismology (IRIS), which is sponsored by the National Science Foundation and has provided a community science facility supporting earthquake science and related disciplines since 1984. These community facilities have included arrays of geophysical instruments operated for EarthScope, an NSF-sponsored science initiative designed to understand the architecture and evolution of the North American continent, as well as the Global Seismographic Network, Greenland Ice Sheet Monitoring Network, a repository of data collected around the world, and other community assets. All data resulting from this facility have been made openly available to support researchers across any field of study and this has expanded the impact of these data beyond disciplinary boundaries. This presentation highlights vivid examples of how basic research activities using open data, collected as part of a community facility, can inform our understanding of manmade earthquakes, geomagnetic hazards, climate change, and illicit testing of nuclear weapons.

Publications - IC 60 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

Mapping Advisory Board STATEMAP Publications Geophysics Program Information Geophysical Survey (500.0 K) Keywords Admiralty Island; Aeromagnetic Data; Aeromagnetic Map; Aeromagnetic Survey; Airborne Geophysical Survey; Alaska Highway Corridor; Alaska Peninsula; Alaska, State of; Ambler; Ambler Mineral Belt

The Environmental Geophysics Web Site and Geophysical Decision Support System (GDSS)

EPA Science Inventory

This product provides assistance to project managers, remedial project managers, stakeholders, and anyone interested in on-site investigations or environmental geophysics. The APM is the beta version of the new U.S. EPA Environmental Geophysics Web Site which includes the Geophys...

36 CFR 902.59 - Geological and geophysical information.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Geological and geophysical information. 902.59 Section 902.59 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT... Geological and geophysical information. Any geological or geophysical information and data (including maps...

Building Geophysics Talent and Opportunity in Africa: Experience from the AfricaArray/Wits Geophysics Field School

NASA Astrophysics Data System (ADS)

Webb, S. J.; Manzi, M.; Scheiber-Enslin, S. E.; Durrheim, R. J.; Jones, M. Q. W.; Nyblade, A.

2015-12-01

There are many challenges faced by geophysics students and academic staff in Africa that make it difficult to develop effective field and research programs. Challenges to conducting field work that have been identified, and that can be tackled are: lack of training on geophysical equipment and lack of exposure to field program design and implementation. To address these challenges, the AfricaArray/Wits Geophysics field school is designed to expose participants to a wide variety of geophysical instruments and the entire workflow of a geophysical project. The AA field school was initially developed for the geophysics students at the University of the Witwatersrand. However, by increasing the number of participants, we are able to make more effective use of a large pool of equipment, while addressing challenging geophysical problems at a remote field site. These additional participants are selected partially based on the likely hood of being able start a field school at their home institution. A good candidate would have access to geophysical equipment, but may not have knowledge of how to use it or how to effectively design surveys. These are frequently junior staff members or graduate students in leadership roles. The three week program introduces participants to the full geophysical field workflow. The first week is spent designing a geophysical survey, including determining the cost. The second week is spent collecting data to address a real geophysical challenge, such as determining overburden thickness, loss of ground features due to dykes in a mine, or finding water. The third week is spent interpreting and integrating the various data sets culminating in a final presentation. Participants are given all lecture material and much of the software is open access; this is done to encourage using the material at the home institution. One innovation has been to use graduate students as instructors, thus building a pool of talent that has developed the logistic and training skills necessary to implement field programs. Several geophysics field schools are being developed in Madagascar, Zimbabwe, Nigeria, Kenya, Uganda, Tanzania and Cameroon. We hope to enable some of our graduate students to help with these budding programs.

Gulf Coast Subsidence: Integration of Geodesy, Geophysical Modeling, and Interferometric Synthetic Aperture Radar Observations

NASA Astrophysics Data System (ADS)

Blom, R. G.; Chapman, B. D.; Deese, R.; Dokka, R. K.; Fielding, E. J.; Hawkins, B.; Hensley, S.; Ivins, E. R.; Jones, C. E.; Kent, J. D.; Liu, Z.; Lohman, R.; Zheng, Y.

2012-12-01

The vulnerability of the US Gulf Coast has received increased attention in the years since hurricanes Katrina and Rita. Agencies responsible for the long-term protection of lives and infrastructure require precise estimates of future subsidence and sea level rise. A quantitative, geophysically based methodology can provide such estimates by incorporating geological data, geodetic measurements, geophysical models of non-elastic mechanical behavior at depth, and geographically comprehensive deformation monitoring made possible with measurements from Interferometric Synthetic Aperture Radar (InSAR). To be effective, results must be available to user agencies in a format suitable for integration within existing decision-support processes. Work to date has included analysis of historical and continuing ground-based geodetic measurements. These reveal a surprising degree of complexity, including regions that are subsiding at rates faster than those considered for hurricane protection planning of New Orleans and other coastal communities (http://www.mvn.usace.army.mil/pdf/hps_verticalsettlement.pdf) as well as Louisiana's coastal restoration strategies (http://www.coast2050.gov/2050reports.htm) (Dokka, 2011, J. Geophys. Res., 116, B06403, doi:10.1029/2010JB008008). Traditional geodetic measurements provide precise information at single points, while InSAR observations provide geographically comprehensive measurements of surface deformation at lower vertical precision. Available InSAR data sources include X-, C- and L-band satellite, and NASA/JPL airborne UAVSAR L-band data. The Gulf Coast environment is very challenging for InSAR techniques, especially with systems not designed for interferometry. For example, the shorter wavelength C-band data decorrelates over short time periods requiring more elaborate time-series analysis techniques, with which we've had some success. Meanwhile, preliminary analysis of limited L-Band ALOS/PALSAR satellite data show promise; unfortunately this Japanese satellite system failed in April 2011. We now have multiple airborne UAVSAR repeat pass interferometry data sets under analysis (http://uavsar.jpl.nasa.gov/) . UAVSAR interferogram processing has proven problematic in this environment, and new acquisitions are planned at shorter temporal intervals to yield improved results. Combining the geodetic and InSAR data can constrain geophysical models of crustal behavior, leading to quantitative predictions of future subsidence. Model results to date show good agreement between geodetic measurements and geophysically reasonable parameters including sediment load and ~130 m post-glacial sea level rise. We review work to date and present newly acquired UAVSAR data.

Genome-to-Watershed Predictive Understanding of Terrestrial Environments

NASA Astrophysics Data System (ADS)

Hubbard, S. S.; Agarwal, D.; Banfield, J. F.; Beller, H. R.; Brodie, E.; Long, P.; Nico, P. S.; Steefel, C. I.; Tokunaga, T. K.; Williams, K. H.

2014-12-01

Although terrestrial environments play a critical role in cycling water, greenhouse gasses, and other life-critical elements, the complexity of interactions among component microbes, plants, minerals, migrating fluids and dissolved constituents hinders predictive understanding of system behavior. The 'Sustainable Systems 2.0' project is developing genome-to-watershed scale predictive capabilities to quantify how the microbiome affects biogeochemical watershed functioning, how watershed-scale hydro-biogeochemical processes affect microbial functioning, and how these interactions co-evolve with climate and land-use changes. Development of such predictive capabilities is critical for guiding the optimal management of water resources, contaminant remediation, carbon stabilization, and agricultural sustainability - now and with global change. Initial investigations are focused on floodplains in the Colorado River Basin, and include iterative model development, experiments and observations with an early emphasis on subsurface aspects. Field experiments include local-scale experiments at Rifle CO to quantify spatiotemporal metabolic and geochemical responses to O2and nitrate amendments as well as floodplain-scale monitoring to quantify genomic and biogeochemical response to natural hydrological perturbations. Information obtained from such experiments are represented within GEWaSC, a Genome-Enabled Watershed Simulation Capability, which is being developed to allow mechanistic interrogation of how genomic information stored in a subsurface microbiome affects biogeochemical cycling. This presentation will describe the genome-to-watershed scale approach as well as early highlights associated with the project. Highlights include: first insights into the diversity of the subsurface microbiome and metabolic roles of organisms involved in subsurface nitrogen, sulfur and hydrogen and carbon cycling; the extreme variability of subsurface DOC and hydrological controls on carbon and nitrogen cycling; geophysical identification of floodplain hotspots that are useful for model parameterization; and GEWaSC demonstration of how incorporation of identified microbial metabolic processes improves prediction of the larger system biogeochemical behavior.

The role of land-climate interactions for the regional amplification of temperature extremes in climate projections

NASA Astrophysics Data System (ADS)

Seneviratne, S. I.; Vogel, M.; Zscheischler, J.; Schwingshackl, C.; Davin, E.; Gudmundsson, L.; Guillod, B.; Hauser, M.; Hirsch, A.; Hirschi, M.; Humphrey, V.; Thiery, W.

2017-12-01

Regional hot extremes are projected to increase more strongly than the global mean temperature, with substantially larger changes than 2°C even if global warming is limited to this level (Seneviratne et al. 2016). This presentation will highlight the processes underlying this behavior, which is strongly related to land-climate feedbacks (Vogel et al. 2017). The identified feedbacks are also affecting the occurrence probability of compound drought and heat events (Zscheischler and Seneviratne 2017), with high relevance for impacts on forest fire and agriculture production. Moreover, the responsible land processes strongly contribute to the inter-model spread in the projections, and can thus be used to derive observations-based constraints to reduce the uncertainty of projected changes in climate extremes. Finally, we will also discuss the role of soil moisture effects on carbon uptake and their relevance for projections, as well as the role of land use changes in affecting the identified feedbacks and projected changes in climate extremes. References: Seneviratne, S.I., M. Donat, A.J. Pitman, R. Knutti, and R.L. Wilby, 2016: Allowable CO2 emissions based on regional and impact-related climate targets. Nature, 529, 477-483, doi:10.1038/nature16542. Vogel, M.M., R. Orth, F. Cheruy, S. Hagemann, R. Lorenz, B.J.J.M. Hurk, and S.I. Seneviratne, 2017: Regional amplification of projected changes in extreme temperatures strongly controlled by soil moisture-temperature feedbacks. Geophysical Research Letters, 44(3), 1511-1519, doi:10.1002/2016GL071235. Zscheischler, J., and S.I. Seneviratne, 2017: Dependence of drivers affects risks associated with compound events. Science Advances, 3(6), doi: 10.1126/sciadv.1700263

Characterisation of the heterogeneity of karst using electrical geophysics - applications in SW China

NASA Astrophysics Data System (ADS)

Binley, A. M.; Cheng, Q.; Tao, M.; Chen, X.

2017-12-01

The southwest China karst region is one of the largest globally continuous karst areas. The great (structural, hydrological and geochemical) complexity of karstic environments and their rapidly evolving nature make them extremely vulnerable to natural and anthropogenic processes/activities. Characterising the location and properties of structures within the karst critical zone, and understanding how the landform is evolving is essential for the mitigation and adaption to locally- and globally-driven changes. Because of the specific nature of karst geology and geomorphology in the humid tropics and subtropics, spatial heterogeneity is high, evidenced by specific landforms features. Such heterogeneity leads to a high dynamic variability of hydrological processes in space and time, along with a complex exchange of surface water and groundwater. Investigating karst hydrogeological features is extremely challenging because of the three-dimensional nature of the system. Observations from boreholes can vary significantly over several metres, making conventional aquifer investigative methods limited. Geophysical methods have emerged as potentially powerful tools for hydrogeological investigations. Geophysical surveys can help to obtain more insight into the complex conduit networks and depth of weathering, both of which can provide quantitative information about the hydrological and hydrochemical dynamics of the system, in addition to providing a better understanding of how critical zone structures have been established and how the landscape is evolving. We present here results from recent geophysical field campaigns in SW China. We illustrate the effectiveness of electrical methods for mapping soil infil in epikarst and report results from field-based investigations along hillslope and valley transects. Our results reveal distinct zones of relatively high electrical conductivity to depths of tens of metres, which we attribute to localised increased fracture density. We discuss how such surveys can be used alongside other investigative techniques to help improve our understanding of the structure and function of this complex subsurface environment.

Coastal bathymetry and backscatter data collected in 2012 from the Chandeleur Islands, Louisiana

USGS Publications Warehouse

DeWitt, Nancy T.; Bernier, Julie C.; Pfeiffer, William R.; Miselis, Jennifer L.; Reynolds, B.J.; Wiese, Dana S.; Kelso, Kyle W.

2014-01-01

As part of the Barrier Island Evolution Research Project, scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center conducted nearshore geophysical surveys off the northern Chandeleur Islands, Louisiana, in July and August of 2012. The objective of the study is to better understand barrier island geomorphic evolution, particularly storm-related depositional and erosional processes that shape the islands over annual to interannual timescales (1-5 years). Collecting geophysical data will allow us to identify relationships between the geologic history of the island and its present day morphology and sediment distribution. This mapping effort was the second in a series of three planned surveys in this area. High resolution geophysical data collected in each of 3 consecutive years along this rapidly changing barrier island system will provide a unique time-series dataset that will significantly further the analyses and geomorphological interpretations of this and other coastal systems, improving our understanding of coastal response and evolution over short time scales (1-5 years). This Data Series report includes the geophysical data that were collected during two cruises (USGS Field Activity Numbers 12BIM03 and 12BIM04) aboard the RV Survey Cat and the RV Twin Vee along the northern portion of the Chandeleur Islands, Breton National Wildlife Refuge, Louisiana. Data were acquired with the following equipment: a Systems Engineering and Assessment, Ltd., SWATHplus interferometric sonar (468 kilohertz (kHz)), an EdgeTech 424 (4-24 kHz) chirp sub-bottom profiling system, and a Knudsen 320BP (210 kHz) echosounder. This report serves as an archive of processed interferometric swath and single-beam bathymetry data. Geographic information system data products include an interpolated digital elevation model, an acoustic backscatter mosaic, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee metadata. NOTE: These data are scientific in nature and are not to be used for navigation.

Preliminary report on geophysical well-logging activity on the Salton Sea Scientific Drilling Project, Imperial Valley, California

USGS Publications Warehouse

Paillet, Frederick L.; Morin, R.H.; Hodges, H.E.

1986-01-01

The Salton Sea Scientific Drilling Project has culminated in a 10,564-ft deep test well, State 2-14 well, in the Imperial Valley of southern California. A comprehensive scientific program of drilling, coring, and downhole measurements, which was conducted for about 5 months, has obtained much scientific information concerning the physical and chemical processes associated with an active hydrothermal system. This report primarily focuses on the geophysical logging activities at the State 2-14 well and provides early dissemination of geophysical data to other investigators working on complementary studies. Geophysical-log data were obtained by a commercial logging company and by the U.S. Geological Survey (USGS). Most of the commercial logs were obtained during three visits to the site; only one commercial log was obtained below a depth of 6,000 ft. The commercial logs obtained were dual induction, natural gamma, compensated neutron formation density, caliper and sonic. The USGS logging effort consisted of four primary periods, with many logs extending below a depth of 6,000 ft. The USGS logs obtained were temperature, caliper, natural gamma, gamma spectral, epithermal neutron, acoustic velocity, full-waveform, and acoustic televiewer. Various problems occurred throughout the drilling phase of the Salton Sea Scientific Drilling Project that made successful logging difficult: (1) borehole constrictions, possibly resulting from mud coagulation, (2) maximum temperatures of about 300 C, and (3) borehole conditions unfavorable for logging because of numerous zones of fluid loss, cement plugs, and damage caused by repeated trips in and out of the hole. These factors hampered and compromised logging quality at several open-hole intervals. The quality of the logs was dependent on the degree of probe sophistication and sensitivity to borehole-wall conditions. Digitized logs presented were processed on site and are presented in increments of 1,000 ft. A summary of the numerous factors that may be relevant to this interpretation also is presented. (Lantz-PTT)

Critical Zone Co-dynamics: Quantifying Interactions between Subsurface, Land Surface, and Vegetation Properties Using UAV and Geophysical Approaches

NASA Astrophysics Data System (ADS)

Dafflon, B.; Leger, E.; Peterson, J.; Falco, N.; Wainwright, H. M.; Wu, Y.; Tran, A. P.; Brodie, E.; Williams, K. H.; Versteeg, R.; Hubbard, S. S.

2017-12-01

Improving understanding and modelling of terrestrial systems requires advances in measuring and quantifying interactions among subsurface, land surface and vegetation processes over relevant spatiotemporal scales. Such advances are important to quantify natural and managed ecosystem behaviors, as well as to predict how watershed systems respond to increasingly frequent hydrological perturbations, such as droughts, floods and early snowmelt. Our study focuses on the joint use of UAV-based multi-spectral aerial imaging, ground-based geophysical tomographic monitoring (incl., electrical and electromagnetic imaging) and point-scale sensing (soil moisture sensors and soil sampling) to quantify interactions between above and below ground compartments of the East River Watershed in the Upper Colorado River Basin. We evaluate linkages between physical properties (incl. soil composition, soil electrical conductivity, soil water content), metrics extracted from digital surface and terrain elevation models (incl., slope, wetness index) and vegetation properties (incl., greenness, plant type) in a 500 x 500 m hillslope-floodplain subsystem of the watershed. Data integration and analysis is supported by numerical approaches that simulate the control of soil and geomorphic characteristic on hydrological processes. Results provide an unprecedented window into critical zone interactions, revealing significant below- and above-ground co-dynamics. Baseline geophysical datasets provide lithological structure along the hillslope, which includes a surface soil horizon, underlain by a saprolite layer and the fractured Mancos shale. Time-lapse geophysical data show very different moisture dynamics in various compartments and locations during the winter and growing season. Integration with aerial imaging reveals a significant linkage between plant growth and the subsurface wetness, soil characteristics and the topographic gradient. The obtained information about the organization and connectivity of the landscape is being transferred to larger regions using aerial imaging and will be used to constrain multi-scale, multi-physics hydro-biogeochemical simulations of the East River watershed response to hydrological perturbations.

Simultaneous Precipitation of Solar Protons and Relativistic Electrons as a New Factor Affecting the Earth's Atmosphere

NASA Astrophysics Data System (ADS)

Shirochkov, A. V.; Sokolov, S. N.

In the field of solar - terrestrial physics during the last decade there has been renewed interest in the effects produced in the Earth atmosphere and ionosphere by fluxes of precipitated highly relativistic electrons. A series of investigation on the subject (preferably by means of satellite measurements) was performed recently, which discussed different aspects of these phenomena called HRE events. More careful study of the HRE events revealed previously unnoticed geophysical phenomenon: a great majority of the solar proton events (SPE) were accompanied by simultaneous precipitation of relativistic electron fluxes. The studies of previous SPE events attributed their atmospheric and ionospheric effects entirely to the solar proton fluxes. It turned out that such an assumption is wrong. Therefore we have actually a new class of geophysical phenomena when the Earth's atmosphere and ionosphere experience combined impact of simultaneously precipitating fluxes of solar protons and relativistic electrons. If one takes into accounts effect of enhanced density of the solar wind during the SPEs (i.e. its dynamic pressure) the real situation during these combined events became more complicated. In this paper the effects during the storm of May 1992 are analyzed as an example of such unusual combination. The methods of separation of the effects produced by different precipitation particles are presented. Other similar events are considered to demonstrate that such complex events are not unique geophysical phenomena.

Geophysical Monitoring Methods Evaluation for the FutureGen 2.0 Project

DOE PAGES

Strickland, Chris E.; USA, Richland Washington; Vermeul, Vince R.; ...

2014-12-31

A comprehensive monitoring program will be needed in order to assess the effectiveness of carbon sequestration at the FutureGen 2.0 carbon capture and storage (CCS) field-site. Geophysical monitoring methods are sensitive to subsurface changes that result from injection of CO 2 and will be used for: (1) tracking the spatial extent of the free phase CO 2 plume, (2) monitoring advancement of the pressure front, (3) identifying or mapping areas where induced seismicity occurs, and (4) identifying and mapping regions of increased risk for brine or CO 2 leakage from the reservoir. Site-specific suitability and cost effectiveness were evaluated formore » a number of geophysical monitoring methods including: passive seismic monitoring, reflection seismic imaging, integrated surface deformation, time-lapse gravity, pulsed neutron capture logging, cross-borehole seismic, electrical resistivity tomography, magnetotellurics and controlled source electromagnetics. The results of this evaluation indicate that CO 2 injection monitoring using reflection seismic methods would likely be difficult at the FutureGen 2.0 site. Electrical methods also exhibited low sensitivity to the expected CO 2 saturation changes and would be affected by metallic infrastructure at the field site. Passive seismic, integrated surface deformation, time-lapse gravity, and pulsed neutron capture monitoring were selected for implementation as part of the FutureGen 2.0 storage site monitoring program.« less

Geophysical Monitoring Methods Evaluation for the FutureGen 2.0 Project

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

Strickland, Chris E.; USA, Richland Washington; Vermeul, Vince R.

A comprehensive monitoring program will be needed in order to assess the effectiveness of carbon sequestration at the FutureGen 2.0 carbon capture and storage (CCS) field-site. Geophysical monitoring methods are sensitive to subsurface changes that result from injection of CO 2 and will be used for: (1) tracking the spatial extent of the free phase CO 2 plume, (2) monitoring advancement of the pressure front, (3) identifying or mapping areas where induced seismicity occurs, and (4) identifying and mapping regions of increased risk for brine or CO 2 leakage from the reservoir. Site-specific suitability and cost effectiveness were evaluated formore » a number of geophysical monitoring methods including: passive seismic monitoring, reflection seismic imaging, integrated surface deformation, time-lapse gravity, pulsed neutron capture logging, cross-borehole seismic, electrical resistivity tomography, magnetotellurics and controlled source electromagnetics. The results of this evaluation indicate that CO 2 injection monitoring using reflection seismic methods would likely be difficult at the FutureGen 2.0 site. Electrical methods also exhibited low sensitivity to the expected CO 2 saturation changes and would be affected by metallic infrastructure at the field site. Passive seismic, integrated surface deformation, time-lapse gravity, and pulsed neutron capture monitoring were selected for implementation as part of the FutureGen 2.0 storage site monitoring program.« less

Publications - AR 2006 | Alaska Division of Geological & Geophysical

Science.gov Websites

Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2006 main content DGGS AR 2006 Publication Details Title: Alaska Division of Geological & Geophysical Surveys Annual

Publications - AR 2000 | Alaska Division of Geological & Geophysical

Science.gov Websites

Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2000 main content DGGS AR 2000 Publication Details Title: Alaska Division of Geological & Geophysical Surveys Annual

Publications - AR 2003 | Alaska Division of Geological & Geophysical

Science.gov Websites

Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2003 main content DGGS AR 2003 Publication Details Title: Alaska Division of Geological & Geophysical Surveys Annual

Publications - AR 2004 | Alaska Division of Geological & Geophysical

Science.gov Websites

Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2004 main content DGGS AR 2004 Publication Details Title: Alaska Division of Geological & Geophysical Surveys Annual

Geophysical data collected from the St. Clair River between Michigan and Ontario, Canada (2008-016-FA)

USGS Publications Warehouse

Denny, Jane F.; Foster, D.S.; Worley, C.R.; Irwin, Barry J.

2011-01-01

In 2008, the U.S. Geological Survey (USGS), Woods Hole Coastal and Marine Science Center (WHCMSC), in cooperation with the U.S. Army Corps of Engineers conducted a geophysical and sampling survey of the riverbed of the Upper St. Clair River between Port Huron, Mich., and Sarnia, Ontario, Canada. The objectives were to define the Quaternary geologic framework of the riverbed of the St. Clair River to evaluate the relationship between morphologic change of the riverbed and underlying stratigraphy. This report presents the geophysical and sample data collected from the St. Clair River, May 29-June 6, 2008, as part of the International Upper Great Lakes Study, a 5-year project funded by the International Joint Commission of the United States and Canada to examine whether physical changes in the St. Clair River are affecting water levels within upper Great Lakes, to assess regulation plans for outflows from Lake Superior, and to examine the potential effect of climate change on the Great Lakes water levels (http://www.iugls.org). This document makes available the data that were used in a separate report, U.S. Geological Survey Open-File Report 2009-1137, which detailed the interpretations of the Quaternary geologic framework of the region. This report includes a description of the high-resolution acoustic and sediment-sampling systems that were used to map the morphology, surficial sediment distribution, and underlying geology of the Upper St. Clair River during USGS field activity 2008-016-FA (http://quashnet.er.usgs.gov/cgi-bin/datasource/public_ds_info.pl?fa=2008-016-FA). Video and photographs of the riverbed were also collected and are included in this data release. Future analyses will be focused on substrate erosion and its effects on river-channel morphology and geometry. Ultimately, the International Upper Great Lakes Study will attempt to determine where physical changes in the St. Clair River affect water flow and, subsequently, water levels in the Upper Great Lakes.

The International Geophysical Month: Short periods of cooperative study can consolidate the gains of the International Geophysical Year.

PubMed

Helliwell, R A; Martin, L H

1961-12-01

For convenience, we summarize below some of the main advantages of the IGM concept. 1) Most organizations can mount and support intensive field operations for short periods. 2) High-quality data would be obtained, and the data could be processed more promptly than in long-term projects. 3) Laboratory equipment could in many instances be mnade available for field operations. 4) Top-caliber researchers would be available for field operations. 5) The participation of small research groups and of research workers from government and industry would be fostered. 6) Student participation would improve educational programs in, and attract needed talent to, the geophysical sciences. 7) Ship, satellite, and rocket observations could be scheduled for IGM's. 8) International scientific conferences scheduled to follow IGM's would attract working scientists. It is not suggested that these short-term exercises should replace the long synoptic programs characteristic of the IGY. Rather it is proposed that they supplement and guide any such future long-term program. If adopted, they would produce many data of value for the planning and timing of the International Year of the Quiet Sun. To bring emphasis on special observations during the IQSY, International Geophysical Months might well be scheduled to coincide with the June and December solstices, to be followed by an IGM at an equinoctial period. This would provide periods for concentrated sampling-periods in somewhat the same category as the Regular World Intervals adopted during the IGY. The more elaborate experiments could be confined to the International Geophysical Months, so that only those studies for which continuous observations are essential would be scheduled for the entire period. The duration of an International Geophysical Month would be sufficient for carrying out experiments requiring moving platforms such as ships, rockets, or satellites. It is recommended that every effort be made to schedule the first IGM during the June solstice in 1962. This initial effort could well be followed by the scheduling of IGM's during the December solstice in 1962 and the March equinox in 1963. These exercises would provide information important to the planning and scheduling of the IQSY (1).

Hydrocarbon Seeps Formations: a Study Using 3-D Seismic Attributes in Combination with Satellite Data

NASA Astrophysics Data System (ADS)

Garcia-Pineda, O. G.; MacDonald, I. R.; Shedd, W.

2011-12-01

Analyzing the magnitude of oil discharges from natural hydrocarbon seeps is important in improving our understanding of carbon contribution as oil migrates from deeper sediments to the water column, and then eventually to the atmosphere. Liquid hydrocarbon seepage in the deep water of the Gulf of Mexico (GOM) is associated with deep cutting faults, associated with vertical salt movement, that provide conduits for the upward migration of oil and gas. Seeps transform surface geology and generate prominent geophysical targets that can be identified on 3-D seismic data as seafloor amplitude anomalies maps that correlate with the underlying deep fault systems. Using 3D seismic data, detailed mapping of the northern GOM has identified more than 21,000 geophysical anomalies across the basin. In addition to seismic data, Synthetic Aperture Radar (SAR) images have proven to be a reliable tool for localizing natural seepage of oil. We used a Texture Classifier Neural Network Algorithm (TCNNA) to process more than 1200 SAR images collected over the GOM. We quantified more than 900 individual seep formations distributed along the continental shelf and in deep water. Comparison of the geophysical anomalies with the SAR oil slick targets shows good general agreement between the distributions of the two indicators. However, there are far fewer active oil slicks than geophysical anomalies, most of which are probably associated with gas seepage. By examining several sites where the location of active venting can be determined by submersibles observations, we found that the active oily vents are often spatially offset from the most intense geophysical targets (i.e. GC600, GC767, GC204, etc). In addition to the displacement of the oil by deep sea currents, we propose that during the 100K years of activity, the location of the vents on the seafloor probably migrate as carbonate cementation reduces the permeability of the upper sediment. Many of the geophysical targets may represent inactive relict sites rather than present day natural seeps of liquid or gaseous hydrocarbon.

Integrated application of in situ non destructive techniques for the evaluation of the architectural elements of monumental structures.

NASA Astrophysics Data System (ADS)

Fais, Silvana; Casula, Giuseppe; Cuccuru, Francesco; Ligas, Paola; Bianchi, Maria Giovanna; Marraccini, Alessandro

2017-04-01

The need to integrate different non invasive geophysical datasets for an effective diagnostic process of the stone materials of cultural heritage buildings is due to the complexity of the intrinsic characteristics of the different types of stones and of their degradation process. Consequently integration between different geophysical techniques is required for the characterization of stone building materials. In order to perform the diagnostic process by different non-invasive techniques thus interpreting in a realistic way the different geophysical parameters, it is necessary to link the petrophysical characteristics of stones with the geophysical ones. In this study the complementary application of three different non invasive techniques (terrestrial laser scanner (TLS), infrared thermography and ultrasonic surface and tomography measurements) was carried out to analyse the conservation state and quality of the carbonate building materials of three inner columns of the old precious church of San Lorenzo in the historical city center of Cagliari (Sardinia). In previous works (Casula et al., 2009; Fais et al., 2015), especially the integrated application of TLS and ultrasonic techniques has been demonstrated to represent a powerful tool in evaluating the quality of the stone building materials by solving or limiting the uncertainties typical of all indirect methods. Thanks to the terrestrial laser scanner (TLS) technique it was possible to 3D model the investigated columns and their surface geometrical anomalies. The TLS measurements were complemented by several ultrasonic in situ and laboratory tests in the 24kHz - 54kHz range. The ultrasonic parameters, especially longitudinal and transversal velocities, allow to recover information on materials related with mechanical properties. A good correlation between TLS surface geometrical anomalies and the ultrasonic velocity ones is evident at the surface and in shallow parts of the investigated architectural elements. To calibrate the geophysical results and provide reliable data for the interpretation, the petrophysical properties (porosity, density, water absorption) and petrographical characteristics (especially texture) of the carbonate building materials under study were examined. By combining petrographical, petrophysical, terrestrial laser scanner and ultrasonic techniques, a consistent diagnostic process of the carbonate building materials can be achieved to detect the presence of defects, fissures, fractures, weathering process or compositional variations. The above diagnostic process is very useful also to evaluate the behavior of the carbonate building materials, facilitating the planning of urgent and long-term conservation programs and in time monitoring. References Casula G, Fais S, Ligas P (2009) Experimental application of 3-D laser scanning and acoustic techniques in assessing the quality of stones used in monumental structures. Int J Microstruct. Mater. Prop. 4:45-56. doi: 10.1504/IJMMP.2009.028432 Fais, S., Cuccuru, F., Ligas, P, Casula, G., Bianchi M.G. (2015) Integrated ultrasonic, laser scanning and petrographical characterisation of carbonate building materials on an architectural structure of a historic building. Bull Eng Geol Environ. doi: 10.1007/s10064-015-0815-9 Acknowledgements: This work was supported by Regione Autonoma della Sardegna (RAS), Regional Law 7th August 2007, n. 7. The authors would also like to thank Archidiocesi di Cagliari and Mons. Mario Ledda for their kind permission to work on the San Lorenzo Church.

How Will Climate Change Impact Cholera Outbreaks?

NASA Astrophysics Data System (ADS)

Nasr Azadani, F.; Jutla, A.; Rahimikolu, J.; Akanda, A. S.; Huq, A.; Colwell, R. R.

2014-12-01

Environmental parameters associated with cholera are well documented. However, cholera continues to be a global public health threat. Uncertainty in defining environmental processes affecting growth and multiplication of the cholera bacteria can be affected significantly by changing climate at different temporal and spatial scales, either through amplification of the hydroclimatic cycle or by enhanced variability of large scale geophysical processes. Endemic cholera in the Bengal Delta region of South Asia has a unique pattern of two seasonal peaks and there are associated with asymmetric and episodic variability in river discharge. The first cholera outbreak in spring is related with intrusion of bacteria laden coastal seawater during low river discharge. Cholera occurring during the fall season is hypothesized to be associated with high river discharge related to a cross-contamination of water resources and, therefore, a second wave of disease, a phenomenon characteristic primarily in the inland regions. Because of difficulties in establishing linkage between coarse resolutions of the Global Climate Model (GCM) output and localized disease outbreaks, the impact of climate change on diarrheal disease has not been explored. Here using the downscaling method of Support Vector Machines from HADCM3 and ECHAM models, we show how cholera outbreak patterns are changing in the Bengal Delta. Our preliminary results indicate statistically significant changes in both seasonality and magnitude in the occurrence of cholera over the next century. Endemic cholera is likely to transform into epidemic forms and new geographical areas will be at risk for cholera outbreaks.

Publications - AR 2011-F | Alaska Division of Geological & Geophysical

Science.gov Websites

project descriptions, in DGGS Staff, Alaska Division of Geological & Geophysical Surveys Annual Report Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2011-F main

Publications - AR 2010-E | Alaska Division of Geological & Geophysical

Science.gov Websites

Communications FY11 project descriptions, in DGGS Staff, Alaska Division of Geological & Geophysical Surveys Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2010-E main

Publications - AR 2010-A | Alaska Division of Geological & Geophysical

Science.gov Websites

FY11 project descriptions, in DGGS Staff, Alaska Division of Geological & Geophysical Surveys Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2010-A main

Publications - AR 2010-F | Alaska Division of Geological & Geophysical

Science.gov Websites

project descriptions, in DGGS Staff, Alaska Division of Geological & Geophysical Surveys Annual Report Visiting Alaska State Employees DGGS State of Alaska search Alaska Division of Geological & Geophysical Facebook DGGS News Natural Resources Geological & Geophysical Surveys Publications AR 2010-F main

Europa: Processes and Habitability

NASA Technical Reports Server (NTRS)

Pappalardo, Robert T.

2006-01-01

This viewgraph presentation reviews the known and possible geologic processes of Europa. It shows slides of Europa, with different terrains (ridged plains and molten plains), and a possible view of the interior. Europa's eccentric orbit is reviewed. The presentation also reviews Europa's composition. The possible reasons for Europa's geology are reviewed. Also the possiblity that life exists on Europa is raised. The planned Europa Geophysical Explorer mission is also reviewed.

Geoinformation web-system for processing and visualization of large archives of geo-referenced data

NASA Astrophysics Data System (ADS)

Gordov, E. P.; Okladnikov, I. G.; Titov, A. G.; Shulgina, T. M.

2010-12-01

Developed working model of information-computational system aimed at scientific research in area of climate change is presented. The system will allow processing and analysis of large archives of geophysical data obtained both from observations and modeling. Accumulated experience of developing information-computational web-systems providing computational processing and visualization of large archives of geo-referenced data was used during the implementation (Gordov et al, 2007; Okladnikov et al, 2008; Titov et al, 2009). Functional capabilities of the system comprise a set of procedures for mathematical and statistical analysis, processing and visualization of data. At present five archives of data are available for processing: 1st and 2nd editions of NCEP/NCAR Reanalysis, ECMWF ERA-40 Reanalysis, JMA/CRIEPI JRA-25 Reanalysis, and NOAA-CIRES XX Century Global Reanalysis Version I. To provide data processing functionality a computational modular kernel and class library providing data access for computational modules were developed. Currently a set of computational modules for climate change indices approved by WMO is available. Also a special module providing visualization of results and writing to Encapsulated Postscript, GeoTIFF and ESRI shape files was developed. As a technological basis for representation of cartographical information in Internet the GeoServer software conforming to OpenGIS standards is used. Integration of GIS-functionality with web-portal software to provide a basis for web-portal’s development as a part of geoinformation web-system is performed. Such geoinformation web-system is a next step in development of applied information-telecommunication systems offering to specialists from various scientific fields unique opportunities of performing reliable analysis of heterogeneous geophysical data using approved computational algorithms. It will allow a wide range of researchers to work with geophysical data without specific programming knowledge and to concentrate on solving their specific tasks. The system would be of special importance for education in climate change domain. This work is partially supported by RFBR grant #10-07-00547, SB RAS Basic Program Projects 4.31.1.5 and 4.31.2.7, SB RAS Integration Projects 4 and 9.

ROV advanced magnetic survey for revealing archaeological targets and estimating medium magnetization

NASA Astrophysics Data System (ADS)

Eppelbaum, Lev

2013-04-01

Magnetic survey is one of most applied geophysical method for searching and localization of any objects with contrast magnetic properties (for instance, in Israel detailed magneric survey has been succesfully applied at more than 60 archaeological sites (Eppelbaum, 2010, 2011; Eppelbaum et al., 2011, 2010)). However, land magnetic survey at comparatively large archaeological sites (with observation grids 0.5 x 0.5 or 1 x 1 m) may occupy 5-10 days. At the same time the new Remote Operation Vehicle (ROV) generation - small and maneuvering vehicles - can fly at levels of few (and even one) meters over the earth's surface (flowing the relief forms or straight). Such ROV with precise magnetic field measurements (with a frequency of 20-25 observations per second) may be performed during 10-30 minutes, moreover at different levels over the earth's surface. Such geophysical investigations should have an extremely low exploitation cost. Finally, measurements of geophysical fields at different observation levels could provide new unique geophysical-archaeological information (Eppelbaum, 2005; Eppelbaum and Mishne, 2011). The developed interpretation methodology for magnetic anomalies advanced analysis (Khesin et al., 1996; Eppelbaum et al., 2001; Eppelbaum et al., 2011) may be successfully applied for ROV magnetic survey for delineation of archaeological objects and estimation averaged magnetization of geological medium. This methodology includes: (1) non-conventional procedure for elimination of secondary effect of magnetic temporary variations, (2) calculation of rugged relief influence by the use of a correlation method, (3) estimation of medium magnetization, (4) application of various informational and wavelet algorithms for revealing low anomalous effects against the strong noise background, (5) advanced procedures for magnetic anomalies quantitative analysis (they are applicable in conditions of rugged relief, inclined magnetization, and an unknown level of the total magnetic field for the models of thin bed, thick bed and horizontal circular cylinder; some of these procedures demand performing measurements at two levels over the earth's surface), (6) advanced 3D magnetic-gravity modeling for complex media, and (7) development of 3D physical-archaeological (or magnetic-archaeological) model of the studied area. ROV observations also permit to realize a multimodel approach to magnetic data analysis (Eppelbaum, 2005). Results of performed 3D modeling confirm an effectiveness of the proposed ROV low-altitude survey. Khesin's methodology (Khesin et al., 2006) for estimation of upper geological section magnetization consists of land magnetic observations along a profile disposing under inclined relief with the consequent data processing (this method cannot be applied at flat topography). The improved modification of this approach is based on combination of straight and inclined ROV observations that will help to obtain parameters of the medium magnetization with areas of flat terrain relief. ACKNOWLEDGEMENT This investigation is funding from the Tel Aviv University - the Cyprus Research Institute combined project "Advanced coupled electric-magnetic archaeological prospecting in Cyprus and Israel". REFERENCES Eppelbaum, L.V., 2005. Multilevel observations of magnetic field at archaeological sites as additional interpreting tool. Proceed. of the 6th Conference of Archaeological Prospection, Roma, Italy, 1-4. Eppelbaum, L.V., 2010. Archaeological geophysics in Israel: Past, Present and Future. Advances of Geosciences, 24, 45-68. Eppelbaum, L.V., 2011. Study of magnetic anomalies over archaeological targets in urban conditions. Physics and Chemistry of the Earth, 36, No. 16, 1318-1330. Eppelbaum, L.V., Alperovich, L., Zheludev, V. and Pechersky, A., 2011. Application of informational and wavelet approaches for integrated processing of geophysical data in complex environments. Proceed. of the 2011 SAGEEP Conference, Charleston, South Carolina, USA, 24, 24-60. Eppelbaum, L.V., Khesin, B.E. and Itkis, S.E., 2001. Prompt magnetic investigations of archaeological remains in areas of infrastructure development: Israeli experience. Archaeological Prospection, 8, No.3, 163-185. Eppelbaum, L.V., Khesin, B.E. and Itkis, S.E., 2010. Archaeological geophysics in arid environments: Examples from Israel. Journal of Arid Environments, 74, No. 7, 849-860. Eppelbaum, L.V. and Mishne, A.R., 2011. Unmanned Airborne Magnetic and VLF investigations: Effective Geophysical Methodology of the Near Future. Positioning, 2, No. 3, 112-133. Khesin, B.E., Alexeyev, V.V. and Eppelbaum, L.V., 1996. Interpretation of Geophysical Fields in Complicated Environments. Kluwer Academic Publishers - Springer, Ser.: Modern Approaches in Geophysics.

Reactive Transport Modeling and Geophysical Monitoring of Bioclogging at Reservoir Scale

NASA Astrophysics Data System (ADS)

Surasani, V.; Commer, M.; Ajo Franklin, J. B.; Li, L.; Hubbard, S. S.

2012-12-01

In Microbial-Enhanced-Hydrocarbon-Recovery (MEHR), preferential bioclogging targets the growth of the biofilms (def. immobilized biopolymers with active cells embodied in it) in highly permeable thief zones to enhance sweep efficiency in oil reservoirs. During MEHR, understanding and controlling bioclogging is hindered by the lack of advanced modeling and monitoring tools; these deficiencies contribute to suboptimal performance. Our focus in this study was on developing a systematic approach to understand and monitor bioclogging at the reservoir scale using a combination of reactive transport modeling and geophysical imaging tools (EM & seismic). In this study, we created a realistic reservoir model from a heterogeneous gas reservoir in the Southern Sacramento basin, California; the model well (Citizen Green #1) was characterized using sonic, electrical, nuclear, and NMR logs for hydrologic and geophysical properties. From the simplified 2D log data model, a strip of size 150m x75m with several high permeability streaks is identified for bioclogging simulation experiments. From the NMR log data it is observed that a good linear correlation exist between logarithmic permeability (0.55- 3.34 log (mD)) versus porosity (0.041-0.28). L. mesenteroides was chosen as the model bacteria. In the presence of sucrose, it enzymatically catalyzes the production of dextran, a useful bioclogging agent. Using microbial kinetics from our laboratory experiment and reservoir heterogeneity, a reactive transport model (RTM) is established for two kinds of bioclogging treatments based on whether microbes are present in situ or are supplied externally. In both cases, sucrose media (1.5 M) is injected at the rate of 1 liter/s for 20 days into the center of high permeable strip to stimulate microbes. Simulations show that the high dextran production was deep into the formation from the injection well. This phenomenon can be explained precisely with bacterial kinetics and injection rate. In the in situ treatment, dextran contributes to a maximum porosity reduction of 9.2%, while in the exogenous microbes treatment, the dextran contributes to a maximum of 10.9% porosity reduction. After RTM, the potential geophysical signature of the treatment was evaluated using previously developed experimental rock physics models and realistic forward modeling approaches. Seismic experiments during dextran production performed by Kwan & Ajo-Franklin (2011) were combined with full waveform viscoelastic modeling to yield a predicted attenuation response from the dextran distributions modeled using RTM. The response suggests that crosswell attenuation tomography may be a viable approach for in situ monitoring of the bioclogging process. Modeling the EM response involved the induced polarization (IP) method, where the simulated resistance amplitude and phase changes can be attributed to porosity reduction. Our studies suggest that the IP signals provide a valuable additional indicator. Both geophysical data methods in a joint imaging approach potentially increase the resolution of each geophysical attribute change. Likewise, reactive transport modeling and geophysical monitoring can provide a powerful tool for predicting different bioclogging scenarios in subsurface. The combination may enhance our capabilities of controlling and monitoring the MEHR bioclogging process at reservoir scale.

Determination of Cenozoic sedimentary structures using integrated geophysical surveys: A case study in the Barkol Basin, Xinjiang, China

NASA Astrophysics Data System (ADS)

Sun, Kai; Chen, Chao; Du, Jinsong; Wang, Limin; Lei, Binhua

2018-01-01

Thickness estimation of sedimentary basin is a complex geological problem, especially in an orogenic environment. Intense and multiple tectonic movements and climate changes result in inhomogeneity of sedimentary layers and basement configurations, which making sedimentary structure modelling difficult. In this study, integrated geophysical methods, including gravity, magnetotelluric (MT) sounding and electrical resistivity tomography (ERT), were used to estimate basement relief to understand the geological structure and evolution of the eastern Barkol Basin in China. This basin formed with the uplift of the eastern Tianshan during the Cenozoic. Gravity anomaly map revealed the framework of the entire area, and ERT as well as MT sections reflected the geoelectric features of the Cenozoic two-layer distribution. Therefore, gravity data, constrained by MT, ERT and boreholes, were utilized to estimate the spatial distribution of the Quaternary layer. The gravity effect of the Quaternary layer related to the Tertiary layer was later subtracted to obtain the residual anomaly for inversion. For the Tertiary layer, the study area was divided into several parts because of lateral difference of density contrasts. Gravity data were interpreted to determine the density contrast constrained by the MT results. The basement relief can be verified by geological investigation, including the uplift process and regional tectonic setting. The agreement between geophysical survey and prior information from geology emphasizes the importance of integrated geophysical survey as a complementary means of geological studies in this region.

Honors

NASA Astrophysics Data System (ADS)

2011-05-01

Among the new members elected to the U.S. National Academy of Sciences in May are five AGU members: Richard Edwards, George and Orpha Gibson Chair of Earth Systems Sciences and Distinguished McKnight University Professor, Department of Geology and Geophysics, University of Minnesota, Minneapolis; T. Mark Harrison, director, Institute of Geophysics and Planetary Physics, and professor of geology, Department of Earth and Space Sciences, University of California, Los Angeles; David Sandwell, professor of geophysics, Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla (president of the AGU Geodesy section); Benjamin Santer, physicist and atmospheric scientist, Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, Calif.; and Steven Wofsy, Abbott Lawrence Rotch Professor of Atmospheric and Environmental Science, Department of Earth and Planetary Sciences, Harvard University, Cambridge, Mass. Four AGU members are among the 2011 prizewinners announced by the Division for Planetary Sciences (DPS) of the American Astronomical Society on 19 May. The prizes will be presented at the joint meeting of DPS and the European Planetary Science Congress in October. William Ward of the Southwest Research Institute, San Antonio, Tex., is the recipient of the Gerard P. Kuiper Prize for outstanding contributions to the field of planetary science. DPS indicated that Ward originally proposed and evaluated “many dynamical processes that are now cornerstones of current theories of how planets form and evolve” and that his “visionary ideas form the foundation for a significant portion of current work in planetary formation and dynamics.”

Crustal insights from gravity and aeromagnetic analysis: Central North Slope, Alaska

USGS Publications Warehouse

Saltus, R.W.; Potter, C.J.; Phillips, J.D.

2006-01-01

Aeromagnetic and gravity data are processed and interpreted to reveal deep and shallow information about the crustal structure of the central North Slope, Alaska. Regional aeromagnetic anomalies primarily reflect deep crustal features. Regional gravity anomalies are more complex and require detailed analysis. We constrain our geophysical models with seismic data and interpretations along two transects including the Trans-Alaska Crustal Transect. Combined geophysical analysis reveals a remarkable heterogeneity of the pre-Mississippian basement. In the central North Slope, pre-Mississippian basement consists of two distinct geophysical domains. To the southwest, the basement is dense and highly magnetic; this basement is likely mafic and mechanically strong, possibly acting as a buttress to basement involvement in Brooks Range thrusting. To the northeast, the central North Slope basement consists of lower density, moderately magnetic rocks with several discrete regions (intrusions?) of more magnetic rocks. A conjugate set of geophysical trends, northwest-southeast and southwest-northeast, may be a factor in the crustal response to tectonic compression in this domain. High-resolution gravity and aeromagnetic data, where available, reflect details of shallow fault and fold structure. The maps and profile models in this report should provide useful guidelines and complementary information for regional structural studies, particularly in combination with detailed seismic reflection interpretations. Future challenges include collection of high-resolution gravity and aeromagnetic data for the entire North Slope as well as additional deep crustal information from seismic, drilling, and other complementary methods. Copyrights ?? 2006. The American Association of Petroleum Geologists. All rights reserved.

Using Grand Challenges For Innovative Teaching in Structural Geology, Geophysics, and Tectonics

NASA Astrophysics Data System (ADS)

McDaris, J. R.; Tewksbury, B. J.; Wysession, M. E.

2012-12-01

An innovative approach to teaching involves using the "Big Ideas" or "Grand Challenges" of a field, as determined by the research community in that area, as the basis for classroom activities. There have been several recent efforts in the areas of structural geology, tectonics, and geophysics to determine these Grand Challenges, including the areas of seismology ("Seismological Grand Challenges in Understanding Earth's Dynamic Systems"), mineral physics ("Unlocking the Building Blocks of the Planet"), EarthScope-related science ("Unlocking the Secrets of the North American Continent: An EarthScope Science Plan for 2010-2020"), and structural geology and tectonics (at the Structural Geology and Tectonics Forum held at Williams College in June, 2012). These research community efforts produced frameworks of the essential information for their fields with the aim of guiding future research. An integral part of this, however, is training the next generation of scientists, and using these Big Ideas as the basis for course structures and activities is a powerful way to make this happen. When activities, labs, and homeworks are drawn from relevant and cutting-edge research topics, students can find the material more fascinating and engaging, and can develop a better sense of the dynamic process of scientific discovery. Many creative ideas for incorporating the Grand Challenges of structural geology, tectonics, and geophysics in the classroom were developed at a Cutting Edge workshop on "Teaching Structural Geology, Geophysics, and Tectonics in the 21st Century" held at the University of Tennessee in July, 2012.

Sensitivity Study for Sensor Optical and Electric Crosstalk Based on Spectral Measurements: An Application to Developmental Sensors Using Heritage Sensors Such As MODIS

NASA Technical Reports Server (NTRS)

Butler, James J.; Oudrari, Hassan; Xiong, Sanxiong; Che, Nianzeng; Xiong, Xiaoxiong

2007-01-01

The process of developing new sensors for space flight frequently builds upon the designs and experience of existing heritage space flight sensors. Frequently in the development and testing of new sensors, problems are encountered that pose the risk of serious impact on successful retrieval of geophysical products. This paper describes an approach to assess the importance of optical and electronic cross-talk on retrieval of geophysical products using new MODIS-like sensors through the use of MODIS data sets. These approaches may be extended to any sensor characteristic and any sensor where that characteristic may impact the Level 1 products so long as validated geophysical products are being developed from the heritage sensor. In this study, a set of electronic and/or optical cross-talk coefficients are postulated. These coefficients are sender-receiver influence coefficients and represent a sensor signal contamination on any detector on a focal plane when another band's detectors on that focal plane are stimulated with a monochromatic light. The approach involves using the postulated cross-talk coefficients on an actual set of MODIS data granules. The original MODIS data granules and the cross-talk impacted granules are used with validated geophysical algorithms to create the derived products. Comparison of the products produced with the original and cross-talk impacted granules indicates potential problems, if any, with the characteristics of the developmental sensor that are being studied.

The Magmatic Structure of Mid-ocean Ridges: Integrating Geophysical and Petrological Observations

NASA Astrophysics Data System (ADS)

Maclennan, J.; Singh, S.

Geophysical surveys, petrological observations and numerical models have all played an important role in the study of magmatic processes at mid-ocean ridges. However, few studies have attempted to integrate the constraints from both geophysical and geochemical observations in order to develop models of mid-ocean ridges. Composi- tional variation within the oceanic crust must be considered when geophysical models are interpreted in terms of variation in temperature or fluid fraction. Modellers com- monly assume that the crust is compositionally homogeneous and that the relationship between temperature and melt fraction does not vary within the crust. However, the compositions of oceanic crustal rocks collected from the Oman ophiolite vary widely and their predicted solidus temperatures vary from 990­1240C and their liquidus temperatures from 1250­1700C. Compositional variation within the solid part of the oceanic crust causes variation in seismic velocities. At fixed temperature and pressure the compositional variation present in crustal rocks can give P-wave velocity variation of 1 km s-1 or more. This has the same effect as a temperature variation of 1500C in the solid or of a variation of 20% in the melt fraction. The importance of this petrolog- ical framework for the interpretation of the seismic structure of mid-ocean ridges and for the development of thermal models of oceanic crustal accretion is demonstrated using an example from the East Pacific Rise near 9N.

Natural disturbance production functions

Treesearch

Jeffrey P. Prestemon; D. Evan Mercer; John M. Pye

2008-01-01

Natural disturbances in forests are driven by physical and biological processes. Large, landscape scale disturbances derive primarily from weather (droughts, winds, ice storms, and floods), geophysical activities (earthquakes, volcanic eruptions), fires, insects, and diseases. Humans have invented ways to minimize their negative impacts and reduce their rates of...

Hiereachical Bayesian Model for Combining Geochemical and Geophysical Data for Environmental Applications Software

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

Chen, Jinsong

2013-05-01

Development of a hierarchical Bayesian model to estimate the spatiotemporal distribution of aqueous geochemical parameters associated with in-situ bioremediation using surface spectral induced polarization (SIP) data and borehole geochemical measurements collected during a bioremediation experiment at a uranium-contaminated site near Rifle, Colorado. The SIP data are first inverted for Cole-Cole parameters including chargeability, time constant, resistivity at the DC frequency and dependence factor, at each pixel of two-dimensional grids using a previously developed stochastic method. Correlations between the inverted Cole-Cole parameters and the wellbore-based groundwater chemistry measurements indicative of key metabolic processes within the aquifer (e.g. ferrous iron, sulfate, uranium)more » were established and used as a basis for petrophysical model development. The developed Bayesian model consists of three levels of statistical sub-models: 1) data model, providing links between geochemical and geophysical attributes, 2) process model, describing the spatial and temporal variability of geochemical properties in the subsurface system, and 3) parameter model, describing prior distributions of various parameters and initial conditions. The unknown parameters are estimated using Markov chain Monte Carlo methods. By combining the temporally distributed geochemical data with the spatially distributed geophysical data, we obtain the spatio-temporal distribution of ferrous iron, sulfate and sulfide, and their associated uncertainity information. The obtained results can be used to assess the efficacy of the bioremediation treatment over space and time and to constrain reactive transport models.« less

Some electrical and magnetic studies of Kilauea Iki lava lake, Hawaii

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

Zablocki, C.J.

1976-01-01

In recent years, the U.S. Geological Survey has been applying various electrical-magnetic (E-M) geophysical techniques to the study of volcanologic processes at Kilauea Volcano, Hawaii. Some of these studies have been directed towards determining the responses of these E-M methods on the cooling and crystallizing lava lake that formed in Kilauea Iki pit crater in 1959. Over the years, this 111 meter-deep ponded body of basaltic magma has served as a natural laboratory for petrologic, geochemical, and geophysical investigations, and hence, has yielded some control for interpreting the resulting E-M data gathered in these studies. A brief discussion of themore » application results, and some tentative conclusions of these studies are presented.« less

Monitoring of Carrying Cable in the Well by Electric Drive of Winch at the Logging Works

NASA Astrophysics Data System (ADS)

Odnokopylov, I. G.; Gneushev, V. V.; Larioshina, I. A.

2016-01-01

Emergency situations during logging operations are considered. The necessity of monitoring of the carrying cable in the well was shown, especially at the jet perforation and seismic researches of wells. The way of monitoring of logging cable and geophysical probe by means of the electric drive of tripping works of the logging winch is offered. This method allows timely to identify the wedges of geophysical equipment and the tension of the cable in well without interfering into construction of logging installation by means of algorithmic processing of sensors of electric drive. Research was conducted on the simulation model; these results indirectly confirm the possibility of using of electric drive for monitoring of downhole equipment.

The effect of wind mixing on the vertical distribution of buoyant plastic debris

NASA Astrophysics Data System (ADS)

Kukulka, T.; Proskurowski, G.; Morét-Ferguson, S.; Meyer, D. W.; Law, K. L.

2012-04-01

Micro-plastic marine debris is widely distributed in vast regions of the subtropical gyres and has emerged as a major open ocean pollutant. The fate and transport of plastic marine debris is governed by poorly understood geophysical processes, such as ocean mixing within the surface boundary layer. Based on profile observations and a one-dimensional column model, we demonstrate that plastic debris is vertically distributed within the upper water column due to wind-driven mixing. These results suggest that total oceanic plastics concentrations are significantly underestimated by traditional surface measurements, requiring a reinterpretation of existing plastic marine debris data sets. A geophysical approach must be taken in order to properly quantify and manage this form of marine pollution.

The lithosphere architecture and geodynamic of the Middle and Lower Yangtze metallogenic belt in eastern China: constraints from integrated geophysical data

NASA Astrophysics Data System (ADS)

Lü, Qingtian; Shi, Danian; Jiang, Guoming; Dong, Shuwen

2014-05-01

The lithosphere structure and deep processes are keys to understanding mineral system and ore-forming processes. Lithosphere-scale process could create big footprints or signatures which can be observed by geophysics methods. SinoProbe has conducted an integrated deep exploration across middle and lower reaches of Yangtze Metallogenic Belt (YMB) in Eastern China, these included broadband seismic, reflection seismic, wide-angle reflection and magnetotellurics survey. Seismic reflection profiles and MT survey were also performed in Luzong, Tongling and Ningwu ore districts to construct 3D geological model. The resulting geophysical data provides new information which help to better understanding the lithosphere structure, geodynamic, deformation and heat and mass transportation that lead to the formation of the Metallogenic Belt. The major results are: (1) Lower velocity body at the top of upper mantle and a SE dipping high velocity body were imaged by teleseismic tomography beneath YMB; (2) Shear wave splitting results show NE parallel fast-wave polarization direction which parallel with tectonic lineament; (3) The reflection seismic data support the crustal-detachment model, the lower and upper crust was detached during contraction deformation near Tanlu fault and Ningwu volcanic basin; (4) Broadband and reflection seismic confirm the shallow Moho beneath YMB; (5) Strong correlation of lower crust reflectivity with magmatism; (6) The lower crust below Luzong Volcanics shows obvious reflective anisotropy both at the crust-mantle transition and the brittle-ductile transition in the crust. All these features suggest that introcontinental subduction, lithosphere delamination, mantle sources magmatic underplating, and MASH process are responsible for the formation of this Mesozoic metallogenic belt. Acknowledgment: We acknowledge the financial support of SinoProbe by the Ministry of Finance and Ministry of Land and Resources, P. R. China, under Grant sinoprobe-03, and financial support by National Natural Science Foundation of China under Grant 40930418

Quantifying Subsurface Water and Heat Distribution and its Linkage with Landscape Properties in Terrestrial Environment using Hydro-Thermal-Geophysical Monitoring and Coupled Inverse Modeling

NASA Astrophysics Data System (ADS)

Dafflon, B.; Tran, A. P.; Wainwright, H. M.; Hubbard, S. S.; Peterson, J.; Ulrich, C.; Williams, K. H.

2015-12-01

Quantifying water and heat fluxes in the subsurface is crucial for managing water resources and for understanding the terrestrial ecosystem where hydrological properties drive a variety of biogeochemical processes across a large range of spatial and temporal scales. Here, we present the development of an advanced monitoring strategy where hydro-thermal-geophysical datasets are continuously acquired and further involved in a novel inverse modeling framework to estimate the hydraulic and thermal parameter that control heat and water dynamics in the subsurface and further influence surface processes such as evapotranspiration and vegetation growth. The measured and estimated soil properties are also used to investigate co-interaction between subsurface and surface dynamics by using above-ground aerial imaging. The value of this approach is demonstrated at two different sites, one in the polygonal shaped Arctic tundra where water and heat dynamics have a strong impact on freeze-thaw processes, vegetation and biogeochemical processes, and one in a floodplain along the Colorado River where hydrological fluxes between compartments of the system (surface, vadose zone and groundwater) drive biogeochemical transformations. Results show that the developed strategy using geophysical, point-scale and aerial measurements is successful to delineate the spatial distribution of hydrostratigraphic units having distinct physicochemical properties, to monitor and quantify in high resolution water and heat distribution and its linkage with vegetation, geomorphology and weather conditions, and to estimate hydraulic and thermal parameters for enhanced predictions of water and heat fluxes as well as evapotranspiration. Further, in the Colorado floodplain, results document the potential presence of only periodic infiltration pulses as a key hot moment controlling soil hydro and biogeochemical functioning. In the arctic, results show the strong linkage between soil water content, thermal parameters, thaw layer thickness and vegetation distribution. Overall, results of these efforts demonstrate the value of coupling various datasets at high spatial and temporal resolution to improve predictive understanding of subsurface and surface dynamics.

Serious games for Geophysics

NASA Astrophysics Data System (ADS)

Lombardo, Valerio; Rubbia, Giuliana

2015-04-01

Childhood stage is indispensable in the education of human beings and especially critical to arise scientific interest in children. We discuss the participatory design of a didactic videogame, i.e. a "serious" game to teach geophysics and Earth sciences to high and low-school students. Geophysics is the application of the laws and techniques of physics to uncover knowledge about the earth's dynamic processes and subsurface structure. It explores phenomena such as earthquakes, volcanoes, tsunamis to improve our understanding of the earth's physical processes and our ability to predict reoccurrences. Effective mitigation of risks from catastrophic geologic hazards requires knowledge and understanding of local geology and geologic processes. Scientific outreach can be defined as discourse activity, whose main objective is to communicate some knowledge previously produced in scientific contexts to a non-expert massive audience. One of the difficulties science educators need to overcome is to explain specific concepts from a given discipline in a language simple and understandable for their audience. Digital games today play a large role in young people's lives. Games are directly connected to the life of today's adolescents. Therefore, digital games should be included and broached as a subject in the classroom. The ardor and enthusiasm that digital games evoke in teenagers has indeed brought many researchers, school leaders and teachers to the question "how video games" can be used to engage young people and support their learning inside the classroom. Additionally, studies have shown that digital games can enhance various skills such as the ability to concentrate, stamina, tactical aptness, anticipatory thinking, orientation in virtual spaces, and deductive reasoning. Thus, videogames become an effective didactic mechanism and should have a place in the classroom. The project aims to explore the potentials of entertainment technologies in educational processes; contribute to innovative pedagogies for scientific learning; create a scientific feedback-loop with students and teachers; implement a multi-level video game for scientific outreach.

Satellite radiothermovision of atmospheric mesoscale processes: case study of tropical cyclones

NASA Astrophysics Data System (ADS)

Ermakov, D. M.; Sharkov, E. A.; Chernushich, A. P.

2015-04-01

Satellite radiothermovision is a set of processing techniques applicable for multisource data of radiothermal monitoring of oceanatmosphere system, which allows creating dynamic description of mesoscale and synoptic atmospheric processes and estimating physically meaningful integral characteristics of the observed processes (like avdective flow of the latent heat through a given border). The approach is based on spatiotemporal interpolation of the satellite measurements which allows reconstructing the radiothermal fields (as well as the fields of geophysical parameters) of the ocean-atmosphere system at global scale with spatial resolution of about 0.125° and temporal resolution of 1.5 hour. The accuracy of spatiotemporal interpolation was estimated by direct comparison of interpolated data with the data of independent asynchronous measurements and was shown to correspond to the best achievable as reported in literature (for total precipitable water fields the accuracy is about 0.8 mm). The advantages of the implemented interpolation scheme are: closure under input radiothermal data, homogeneity in time scale (all data are interpolated through the same time intervals), automatic estimation of both the intermediate states of scalar field of the studied geophysical parameter and of vector field of effective velocity of advection (horizontal movements). Using this pair of fields one can calculate the flow of a given geophysical quantity though any given border. For example, in case of total precipitable water field, this flow (under proper calibration) has the meaning of latent heat advective flux. This opportunity was used to evaluate the latent heat flux though a set of circular contours, enclosing a tropical cyclone and drifting with it during its evolution. A remarkable interrelation was observed between the calculated magnitude and sign of advective latent flux and the intensity of a tropical cyclone. This interrelation is demonstrated in several examples of hurricanes and tropical cyclones of August, 2000, and typhoons of November, 2013, including super typhoon Haiyan.

Physical characteristics of dungeness crab and halibut habitats in Glacier Bay

USGS Publications Warehouse

Cochrane, Guy R.; Carlson, Paul R.; Denny, Jane F.; Boyle, Michael E.; Taggart, S. James; Hooge, Philip N.

1998-01-01

In Glacier Bay National Park, Alaska there are ongoing studies of Dungeness Crab (Cancer magister) and Pacific Halibut (Hippoglosus stenolepis). Scientists of the United States Geological Survey (USGS) are attempting to ascertain life history, distribution, and abundance, and to determine the effects of commercial fishing in the park (Carlson et al., 1998). Statistical sampling studies suggest that seafloor characteristics and bathymetry affect the distribution, abundance and behavior of benthic species. Examples include the distribution of Dungeness crab which varies from 78 to 2012 crabs/ha in nearshore areas to depths of 18 m (O'Clair et al., 1995), and changes in halibut foraging behavior according to bottom type (Chilton et al., 1995). This report discusses geophysical data collected in six areas within the park in 1998. The geophysical surveying done in this and previous studies will be combined with existing population and sonic-tracking data sets as well as future sediment sampling, scuba, submersible, and bottom video camera observations to better understand Dungeness crab and Pacific halibut habitat relationships.

Physical characteristics of dungeness crab and halibut habitats in Whidbey Passage, Alaska

USGS Publications Warehouse

Cochrane, Guy R.; Carlson, Paul R.; Boyle, Michael E.; Gabel, Gregory L.; Hooge, Philip N.

2000-01-01

In Glacier Bay National Park, Alaska there are ongoing studies of Dungeness Crab (Cancer magister) and Pacific Halibut (Hippoglosus stenolepis). Scientists of the United States Geological Survey (USGS) are attempting to ascertain life history, distribution, and abundance, and to determine the effects of commercial fishing in the park (Carlson et al., 1998). Statistical sampling studies suggest that seafloor characteristics and bathymetry affect the distribution, abundance and behavior of benthic species. Examples include the distribution of Dungeness crab which varies from 78 to 2012 crabs/ha in nearshore areas to depths of 18 m (O'Clair et al., 1995), and changes in halibut foraging behavior according to bottom type (Chilton et al., 1995). This report discusses geophysical data collected within the park in 1998. The geophysical surveying done in this and previous studies will be combined with existing population and sonic-tracking data sets as well as future sediment sampling, scuba, submersible, and bottom video camera observations to better understand Dungeness crab and Pacific halibut habitat relationships.

Estimation of Water Within the Lithospheric Mantle of Central Tibet from Petrological-Geophysical Investigations

NASA Astrophysics Data System (ADS)

Vozar, J.; Fullea, J.; Jones, A. G.

2013-12-01

Investigations of the lithosphere and sub-lithospheric upper mantle by integrated petrological-geophysical modeling of magnetotelluric (MT) and seismic surface-wave data, which are differently sensitive to temperature and composition, allows us to reduce the uncertainties associated with modeling these two data sets independently, as commonly undertaken. We use selected INDEPTH MT data, which have appropriate dimensionality and large penetration depths, across central Tibet for 1D modeling. Our deep resistivity models from the data can be classified into two different and distinct groups: (i) the Lhasa Terrane and (ii) the Qiangtang Terrane. For the Lhasa Terrane group, the models show the existence of upper mantle conductive layer localized at depths of 200 km, whereas for the Qiangtang Terrane, this conductive layer is shallower at depths of 120 km. We perform the integrated geophysical-petrological modeling of the MT and surface-wave data using the software package LitMod. The program facilitates definition of realistic temperature and pressure distributions within the upper mantle for given thermal structure and oxide chemistry in the CFMAS system. This allows us to define a bulk geoelectric and seismic model of the upper mantle based on laboratory and xenolith data for the most relevant mantle minerals, and to compute synthetic geophysical observables. Our results suggest an 80-120 km-thick, dry lithosphere in the central part of the Qiangtang Terrane. In contrast, in the central Lhasa Terrane the predicted MT responses are too resistive for a dry lithosphere regardless its thickness; according to seismic and topography data the expected lithospheric thickness is about 200 km. The presence of small amounts of water significantly decreases the electrical resistivity of mantle rocks and is required to fit the MT responses. We test the hypothesis of small amounts of water (ppm scale) in the nominally anhydrous minerals of the lithospheric mantle. Such a small amount of water dramatically affects the resistivity but has no influence on the seismic velocities (and therefore, the calculated surface wave's dispersion curves are unaffected too). Three different proton conduction models for olivine conductivity (1 - Wang et al., 2006; 2 - Yoshino et al., 2009; 3 -Jones et al., 2012) and two water partition coefficients are tested. The presence of water in lithospheric mantle is decreased from 170 km to the LAB depth at 200 km. If we move this water-presentbottom boundary to shallower depth, the lithospheric mantle becomes too resistive. Our results favour a moderately wet (<0.01 wt%) mantle above the underthrusted Indian lithosphere, probably as a result of the dehydration processes. The presence of percolating water-rich fluids has the additional effect of lowering the solidus, and therefore facilitating partial melting in the warm lower crust of Lhasa.

Geophysical Institute. Biennial report, 1993-1994

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

NONE

1996-01-01

The 1993-1994 Geophysical Institute Biennial Report was published in November 1995 by the Geophysical Institute of the University of Alaska Fairbanks. It contains an overview of the Geophysical Institute, the Director`s Note, and research presentations concerning the following subjects: Scientific Predictions, Space Physics, Atmospheric Sciences, Snow, Ice and Permafrost, Tectonics and Sedimentation, Seismology, Volcanology, Remote Sensing, and other projects.

Fundamentals of Geophysics

NASA Astrophysics Data System (ADS)

Lowrie, William

1997-10-01

This unique textbook presents a comprehensive overview of the fundamental principles of geophysics. Unlike most geophysics textbooks, it combines both the applied and theoretical aspects to the subject. The author explains complex geophysical concepts using abundant diagrams, a simplified mathematical treatment, and easy-to-follow equations. After placing the Earth in the context of the solar system, he describes each major branch of geophysics: gravitation, seismology, dating, thermal and electrical properties, geomagnetism, paleomagnetism and geodynamics. Each chapter begins with a summary of the basic physical principles, and a brief account of each topic's historical evolution. The book will satisfy the needs of intermediate-level earth science students from a variety of backgrounds, while at the same time preparing geophysics majors for continued study at a higher level.

Scatterometer capabilities in remotely sensing geophysical parameters over the ocean: The status and the possibilities

NASA Technical Reports Server (NTRS)

Brown, R. A.

1984-01-01

Extensive comparison between surface measurements and satellite Scatt signal and predicted winds show successful wind and weather analysis comparable with conventional weather service analyses. However, in regions often of the most interest, e.g., fronts and local storms, inadequacies in the latter fields leaves an inability to establish the satellite sensor capabilities. Thus, comparisons must be made between wind detecting measurements and other satellite measurements of clouds, moisture, waves or any other parameter which responds to sharp gradients in the wind. At least for the windfields and the derived surface pressure field analysis, occasional surface measurements are required to anchor and monitor the satellite analyses. Their averaging times must be made compatible with the satellite sensor measurement. Careful attention must be paid to the complex fields which contain many scales of turbulence and coherent structures affecting the averaging process. The satellite microwave system is capable of replacing the conventional point observation/numerical analysis for the ocean weather.

Interferometric imaging of the 2011-2013 Campi Flegrei unrest

NASA Astrophysics Data System (ADS)

De Siena, Luca; Nakahara, Hisashi; Zaccarelli, Lucia; Sammarco, Carmelo; La Rocca, Mario; Bianco, Francesca

2017-04-01

After its 1983-84 seismic and deformation crisis, seismologists have recorded very low and clustered seismicity at Campi Flegrei caldera (Italy). Hence, noise interferometry imaging has become the only option to image the present volcano logical state of the volcano. Three-component noise data recorded before, during, and after Campi Flegrei last deformation and geochemical unrest (2011-2013) have thus been processed with up-to-date interferometric imaging workflow based on MSNoise. Noise anisotropy, which strongly affects measurements throughout the caldera at all frequencies, has been accounted for by self-correlation measurements and smoothed by phase weighted stacking and phase-match filtering. The final group-velocity maps show strong low-velocity anomalies at the location of the last Campi Flegrei eruption (1538 A.D.). The main low-velocity anomalies contour Solfatara volcano and follow geomorphological cross-faulting. The comparison with geophysical imaging results obtained during the last seismic unrest at the caldera suggest strong changes in the physical properties of the volcano, particularly in the area of major hydrogeological hazard.

Current Limitations on VLBI Accuracy

NASA Technical Reports Server (NTRS)

Ma, Chopo; Gipson, John; MacMillan, Daniel

1998-01-01

The contribution of VLBI to geophysics and geodesy arises from its ability to measure distances between stations in a network and to determine the orientation of stations in the network as well as the orientation of the network with respect to the external reference frame of extragalactic radio objects. Integrating nearly two decades of observations provides useful information about station positions and velocities and the orientation of the Earth, but the complications of the real world and the limitations of observing, modeling and analysis prevent recovery of all effects. Of the factors that limit the accuracy of seemingly straightforward geodetic parameters, the neutral propagation medium has been subject to the greatest scrutiny, but the treatment of the mapping function, the wet component and spatial/temporal inhomogeneities is still improving. These affect both the terrestrial scale and consistency over time. The modeling of non-secular site motions (tides and loading) has increased in sophistication, but there are some differences between the models and the observations. VLBI antennas are massive objects, so their behavior is quite unlike GPS monuments, but antenna deformations add some (generally) unmodeled signal. Radio sources used in geodetic VLBI observations are selected for strength and (relative) absence of structure, but apparent changes in position can leak into geodetic parameters. A linear rate of change of baseline or site parameters is the simplest model and its error improves with time span. However, in most cases the VLBI data distribution is insufficient to look for real non-linear behavior that might affect the average rate. A few sites have multiple VLBI antennas, and some show small differences in rate. VLBI intrinsically measures relative positions and velocities, but individual site positions and velocities are generally more useful. The creation of the VLBI terrestrial reference frame, which transforms relative information into individual results, is an empirical process that has intrinsic errors. While UT1 is uniquely measured by VLBI, the geographical distribution and availability of VLBI stations, especially in the southern hemisphere, and the consistency of the VLBI terrestrial reference frame may limit the accuracy of Earth orientation measurements. The effects of particular error sources on geodetic and geophysical parameters derived from VLBI data will be illustrated.

Assessment of local hydraulic properties from electrical resistivity tomography monitoring of a three-dimensional synthetic tracer test experiment

NASA Astrophysics Data System (ADS)

Camporese, M.; Cassiani, G.; Deiana, R.; Salandin, P.

2011-12-01

In recent years geophysical methods have become increasingly popular for hydrological applications. Time-lapse electrical resistivity tomography (ERT) represents a potentially powerful tool for subsurface solute transport characterization since a full picture of the spatiotemporal evolution of the process can be obtained. However, the quantitative interpretation of tracer tests is difficult because of the uncertainty related to the geoelectrical inversion, the constitutive models linking geophysical and hydrological quantities, and the a priori unknown heterogeneous properties of natural formations. Here an approach based on the Lagrangian formulation of transport and the ensemble Kalman filter (EnKF) data assimilation technique is applied to assess the spatial distribution of hydraulic conductivity K by incorporating time-lapse cross-hole ERT data. Electrical data consist of three-dimensional cross-hole ERT images generated for a synthetic tracer test in a heterogeneous aquifer. Under the assumption that the solute spreads as a passive tracer, for high Peclet numbers the spatial moments of the evolving plume are dominated by the spatial distribution of the hydraulic conductivity. The assimilation of the electrical conductivity 4D images allows updating of the hydrological state as well as the spatial distribution of K. Thus, delineation of the tracer plume and estimation of the local aquifer heterogeneity can be achieved at the same time by means of this interpretation of time-lapse electrical images from tracer tests. We assess the impact on the performance of the hydrological inversion of (i) the uncertainty inherently affecting ERT inversions in terms of tracer concentration and (ii) the choice of the prior statistics of K. Our findings show that realistic ERT images can be integrated into a hydrological model even within an uncoupled inverse modeling framework. The reconstruction of the hydraulic conductivity spatial distribution is satisfactory in the portion of the domain directly covered by the passage of the tracer. Aside from the issues commonly affecting inverse models, the proposed approach is subject to the problem of the filter inbreeding and the retrieval performance is sensitive to the choice of K prior geostatistical parameters.

Geophysical investigation of subrosion processes - an integrated approach

NASA Astrophysics Data System (ADS)

Miensopust, Marion; Hupfer, Sarah; Kobe, Martin; Schneider-Löbens, Christiane; Wadas, Sonja; Krawczyk, Charlotte

2016-04-01

Subrosion, i.e., leaching of readily soluble rocks mostly due to groundwater, is usually of natural origin but can be enhanced by anthropogenic interferences. In recent years, public awareness of subrosion processes in terms of the in parts catastrophic implications and incidences increased. Especially the sinkholes in Schmalkalden and Tiefenort (Germany) are - based on unforeseen collapse events and associated damage in 2010 - two dramatic examples. They illustrate that to date the knowledge of those processes and therefore the predictability of such events is insufficient. The complexity of the processes requires an integrated geophysical approach which investigates the interlinking of structure, hydraulics, solution processes, and mechanics. This finally contributes to a better understanding of the processes by reliable imaging and characterisation of subrosion structures. At LIAG an inter-sectional group is engaged in geophysical investigation of subrosion processes. The focus is application, enhancement and combination of various geophysical methods both at surface and in boreholes. This includes monitoring of (surface) deformation and variation of gravity as well as seismic, geoelectric and electromagnetic methods. Petrophysical investigations (with focus on spectral induced polarisation - SIP) are conducted to characterise the processes on pore scale. Numerical studies are applied to advance the understanding of void forming processes and the mechanical consequences in the dynamic interaction. Since March 2014, quarterly campaigns are conducted to monitor time-lapse gravity changes at 12 stations in the urban area of Bad Frankenhausen. The standard deviations of the gravity differences between the survey points are low and the accompanying levelling locally shows continuous subsidence in the mm/year-range. Eight shear-wave reflection seismic profiles were surveyed in Bad Frankenhausen using a landstreamer and an electro-dynamic vibrator. This method is suitable for high-resolution imaging of near-surface subrosion structures. The analysis revealed a heterogeneous underground with fractures, faults and depression-structures and variations of traveltime, absorption and scattering of seismic waves. Electric and electromagnetic methods have been used to investigate the geological structure of a karst system (e.g. banking and dipping of limestone) based on the different bulk resistivities of the various geological units and reflections of electromagnetic waves at interfaces. The borehole georadar has successfully been used to detect a cavity and areas of disruption. First results of laboratory SIP measurements on different carbonates show clearly polarization effects and a strong relationship between real and imaginary part of electrical conductivity. All samples of Edwards Brown carbonates show a significant phase peak and the same chemism. Therefore, they are ideal for a more systematic study to derive robust empirical relations between IP and petrophysical parameters. Numerical modelling is applied to simulate the collapse mechanism and rock failure to specify the conditions in which sinkholes form. Important parameters for failure are thickness of overburden, lateral dimension and shape of the cavity, existing fracture network and layer boundaries, which partly can be provided by the other methods. This diversity of methods allows a characterisation of karst systems and subrosion structures based on various complementary properties and on many scales from pore size to the big picture of the karst system.

Error characterization of microwave satellite soil moisture data sets using fourier analysis

USDA-ARS?s Scientific Manuscript database

Abstract: Soil moisture is a key geophysical variable in hydrological and meteorological processes. Accurate and current observations of soil moisture over mesoscale to global scales as inputs to hydrological, weather and climate modelling will benefit the predictability and understanding of these p...

Integration of Landsat, Seasat, and other geo-data sources

NASA Technical Reports Server (NTRS)

Zobrist, A. L.; Blackwell, R. J.; Stromberg, W. D.

1979-01-01

The paper discusses integration of Landsat, Seasat, and other geographic information sources. Mosaicking of radar data and registration of radar to Landsat digital imagery are described, and six types of geophysical data, including gravity and magnetic measurements, are integrated and analyzed using image processing techniques.

Multi-array borehole resistivity and induced polarization method with mathematical inversion of redundant data

DOEpatents

Ward, Stanley H.

1989-01-01

Multiple arrays of electric or magnetic transmitters and receivers are used in a borehole geophysical procedure to obtain a multiplicity of redundant data suitable for processing into a resistivity or induced polarization model of a subsurface region of the earth.

Methodology of Detailed Geophysical Examination of the Areas of World Recognized Religious and Cultural Artifacts

NASA Astrophysics Data System (ADS)

Eppelbaum, Lev

2010-05-01

It is obvious that noninvasive geophysical methods are the main interpreting tools at the areas of world recognized religious and cultural artifacts. Usually in these areas any excavations, drilling and infrastructure activity are forbidden or very strongly limited. According to field experience and results of numerous modeling (Eppelbaum, 1999, 2000, 2009a, 2009b; Eppelbaum and Itkis, 2001, 2003; Eppelbaum et al., 2000, 2001a, 2001b, 2003a, 2006a, 2006b, 2007, 2010, Itkis et al., 2003; Neishtadt et al., 2006), a set of applied geophysical methods may include the following types of surveys: (1) magnetic, (3) GPR (ground penetration radar), (3) gravity, (4) electromagnetic VLF (very low frequency), (5) ER (electric resistivity), (6) SP (self-potential), (7) IP (induced polarization), (8) SE (seismoelectric), and (9) NST (near-surface temperature). As it was shown in (Eppelbaum, 2005), interpretation ambiguity may be sufficiently reduced not only by integrated analysis of several geophysical methods, but also by the way of multilevel observations of geophysical fields. Magnetic, gravity and VLF measurements may be performed at different levels over the earth's surface (0.1 - 3 m), ER, SP and SE observations may be obtained with different depth of electrodes grounding (0.1 - 1 m), and NST sensor may be located at a depth of 0.8 - 2.5 m. GPR method usually allows measuring electromagnetic fields at various frequencies (with corresponding changing of the investigation depth and other parameters). Influence of some typical noise factors to geophysical investigations at archaeological sites was investigated in (Eppelbaum and Khesin, 2001). In many cases various constructions and walls are in the nearest vicinity of the examined artifacts. These constructions can be also utilized for carrying out geophysical measurements (magnetic, gravity and VLF) at different levels. Application of the modern ROV (remote operated vehicles) with registration of magnetic and VLF fields at the low altitudes (3-5 meters) will help geophysical cover all the studied area with a regular observation step (Eppelbaum, 2008). At the final step all these measurements (including results of the previous works) could be compiled to 4D models of different geophysical parameters (Eppelbaum and Ben-Avraham, 2002; Eppelbaum et al., 2010). Analysis of temperature field in the boreholes drilled in the vicinity of the studied site will permit to estimate the temperature (e.g., Eppelbaum et al., 2006c) in the historical period when this artifact was constructed and, correspondingly, utilize this characteristic for investigation of mechanical and other properties of the ancient building material. Studying of temporal variations of magnetic (e.g., Finkelstein and Eppelbaum) and VLF fields can be also used for determination of nature of some buried ancient remains. The geophysical investigations must be combined with geochemical, paleostructural, paleobiogeographical, paleomorphological and other methods (Eppelbaum et al., 2010). Application of informational parameters (Khesin et al., 1996; Eppelbaum et al., 2003b) will permit to present all available data by the use of integral convolution units. REFERENCES Eppelbaum, L.V., 1999. Quantitative interpretation of resistivity anomalies using advanced methods developed in magnetic prospecting. Trans. of the XXIV General Assembly of the Europ. Geoph. Soc., Strasburg 1 (1), p.166. Eppelbaum, L.V., 2000. Applicability of geophysical methods for localization of archaeological targets: An introduction. Geoinformatics, 11, No.1, 19-28. Eppelbaum, L.V., 2005. Multilevel observations of magnetic field at archaeological sites as additional interpreting tool. Proceed. of the 6th Conference of Archaeological Prospection, Roma, Italy, 4 pp. Eppelbaum, L.V., 2008. Remote operated vehicle geophysical survey using magnetic and VLF methods: proposed schemes for data processing and interpretation. Proceed. of the Symp. on the Application of Geophysics to Engineering and Environmental Problems, Philadelphia, USA, 938-963. Eppelbaum, L.V., 2009a. Near-surface temperature survey: An independent tool for buried archaeological targets delineation. Journal of Cultural Heritage, 12, Suppl.1, e93-e103. Eppelbaum, L.V., 2009b. Application of microgravity at archaeological sites in Israel: some estimation derived from 3D modeling and quantitative analysis of gravity field. Proceed. of the Symp. on the Application of Geophysics to Engineering and Environmental Problems, Denver, USA, 22, No. 1, 434-446. Eppelbaum, L. and Ben-Avraham, Z., 2002. On the development of 4D geophysical Data Base of archaeological sites in Israel. Trans. of the Conf. of the Israel Geol. Soc. Ann. Meet., MaHagan - Lake Kinneret, Israel, p.21. Eppelbaum, L., Eppelbaum,V. and Ben-Avraham, Z., 2003. Formalization and estimation of integrated geological investigations: Informational Approach. Geoinformatics, 14, No.3, 233-240. Eppelbaum, L., Ben-Avraham, Z. and Itkis, S., 2003a. Ancient Roman Remains in Israel provide a challenge for physical-archaeological modeling techniques. First Break, 21 (2), 51-61. Eppelbaum, L., Ben-Avraham, Z., Itkis, S., and Kouznetsov, S., 2001a. First results of self-potential method application at archaeological sites in Israel. Trans. of the EUG XI Intern. Symp., Strasbourg, France, p. 657. Eppelbaum, L.V. and Itkis, S.E., 2001. Detailed magnetic investigations at the ancient Roman site Banias II (northern Israel). Proceed. of the 1st Intern Symp. on Soil and Archaeology, Szazhalombatta, Hungary, 13-16. Eppelbaum, L.V. and Itkis, S.E., 2003. Geophysical examination of the archaeological site Emmaus-Nicopolis (central Israel). Collection of Papers of the XIXth International UNESCO Symposium 'New Perspectives to Save the Cultural Heritage', Antalya, Turkey, 395-400. Eppelbaum, L.V., Itkis, S.E., Fleckenstein, K.-H., and Fleckenstein, L., 2007. Latest results of geophysical-archaeological investigations at the Christian archaeological site Emmaus-Nicopolis (central Israel). Proceed. of the 69th EAGE Conference, P118, London, Great Britain, 5 pp. Eppelbaum, L.V., Itkis, S.E., and Khesin, B.E., 2000. Optimization of magnetic investigations in the archaeological sites in Israel. In: Special Issue of Prospezioni Archeologiche 'Filtering, Modeling and Interpretation of Geophysical Fields at Archaeological Objects', 65-92. Eppelbaum, L., Itkis, S., and Khesin, B., 2006a. Detailed magnetic survey unmasks Prehistoric archaeological sites in Israel. Proceed. of the Symp. on the Application of Geophysics to Engineering and Environmental Problems, Calgary, Canada, 1366-1373. Eppelbaum, L.V. and Khesin, B.E., 2001. Disturbing factors in geophysical investigations at archaeological sites and ways of their elimination. Trans. of the IV Conf. on Archaeological Prospection, Vienna, Austria, 99-101. Eppelbaum, L.V., Khesin, B.E., and Itkis, S.E., 2001b. Prompt magnetic investigations of archaeological remains in areas of infrastructure development: Israeli experience. Archaeological Prospection, 8 (3), 163-185. Eppelbaum, L.V., Khesin, B.E., and Itkis, S.E., 2006b. Some peculiarities of geophysical investigations at archaeological sites in Israel. Russian Archaeology, No. 1, 59-70. Eppelbaum, L.V., Khesin, B.E., and Itkis, S.E., 2010. Archaeological geophysics in arid environments: Examples from Israel. Journal of Arid Environments, 74, No. 5. Eppelbaum, L.V., Kutasov, I.M. and Barak, G., 2006c. Ground surface temperature histories inferred from 15 boreholes temperature profiles: Comparison of two approaches. Earth Sciences Research Journal, 10, No. 1, 25-34. Finkelstein, M.I. and Eppelbaum, L.V., 1997. Classification of the disturbing objects using interpretation of low-intensive temporary magnetic variations. Trans. of the Conference of Geological Society of America. Salt Lake City, 29, No.6, p. 326. Itkis, S., Khesin, B., Eppelbaum, L., and Khalaily, H., 2003. The Natufian site of Eynan (Hula valley, northern Israel): Magnetic prospecting reveals new features. Israel Journal of Earth Sciences, 52 (3-4), 209-219. Khesin, B.E., Alexeyev, V.V. and Eppelbaum, L.V., 1996. Interpretation of Geophysical Fields in Complicated Environments. Kluwer Academic Publishers, Ser.: Modern Approaches in Geophysics, Boston - Dordrecht - London, 368 pp. Neishtadt, N., Eppelbaum, L. and Levitski, A., 2006. Application of seismo-electric phenomena in exploration geophysics: Review of Russian and Israeli experience. Geophysics, 71, No.2, B41-B53.

U.S.-Soviet Collaborative Geological and Geophysical Survey of the Mid-Atlantic Ridge near 31 degrees N, the Petrov Fracture Zone

USGS Publications Warehouse

Klitgord, Kim D.; Dmitriev, Leonard V.; Casey, John F.; Silantiev, Sergei; Johnson, Kevin

1993-01-01

IntroductionIn February 1989, the first formal U.S.-Soviet joint marine geologic-geophysical study in 10 years was undertaken along the Mid-Atlantic Ridge near 31°N on the 12th Cruise of the RN Akademik Boris Petrov of the Vernadsky Institute of Geochemistry (USSR Academy of Sciences, Moscow). This survey was initiated as part of the U.S.S.R.-U.S. cooperative research project "Mid-Atlantic Ridge Crest Processes" within the framework of the Soviet-U.S. bilateral Ocean Studies Agreement (Ostenso, 1989). U.S. scientists from the U.S. Geological Survey, University of Houston, and Woods Hole Oceanographic Institution participated in this program with Soviet scientists from the Vernadsky Institute of Geochemistry, Institute of Geology, and Schmidt Institute of Physics of the Earth, all institutes of the USSR Academy of Sciences in Moscow (Appendix 1 ). The ship departed from Rotterdam, Nederlands on February 2, 1989 and docked in Bridgetown, Barbados on February 28, 1989. A log of the ship's schedule during this cruise is given in Appendix 2. This study involved a limited multibeam-bathymetric, gravity, magnetic, and seismic- reflection survey. and dredging program of a short-offset transform fault named the Petrov Fracture Zone near 31 °N, located just north of the Atlantis Fracture Zone on the Mid Atlantic Ridge. A site survey at King's Trough in the northeast Atlantic for a MIR submersible program in June 1989 was originally planned as part of this program, but bad weather and the resultant poor quality geophysical data forced this work to be terminated after only one day. Nearly 6000 km of geophysical profile data and 13 dredge stations were completed during this cruise. A description of the geophysical systems aboard the RN Petrov is given in Appendices 3 and 4. All geophysical data were recorded on magnetic tape in data formats described in Appendix 5. Dredge locales and description summaries only are presented in Appendix 6. Detailed descriptions of dredge samples will be presented elsewhere. Operational plan for the studies on this cruise was developed as a cooperative effort between U.S. and Soviet scientists, who established jointly the basic objectives of the study. The U.S. scientists were given the responsibility for developing the detailed survey and dredge sampling plans. Dredge operations and basic geophysical systems operations were the responsibility of the Soviet personnel.

Geophysical constraints on geodynamic processes at convergent margins: A global perspective

NASA Astrophysics Data System (ADS)

Artemieva, Irina; Thybo, Hans; Shulgin, Alexey

2016-04-01

Convergent margins, being the boundaries between colliding lithospheric plates, form the most disastrous areas in the world due to intensive, strong seismicity and volcanism. We review global geophysical data in order to illustrate the effects of the plate tectonic processes at convergent margins on the crustal and upper mantle structure, seismicity, and geometry of subducting slab. We present global maps of free-air and Bouguer gravity anomalies, heat flow, seismicity, seismic Vs anomalies in the upper mantle, and plate convergence rate, as well as 20 profiles across different convergent margins. A global analysis of these data for three types of convergent margins, formed by ocean-ocean, ocean-continent, and continent-continent collisions, allows us to recognize the following patterns. (1) Plate convergence rate depends on the type of convergent margins and it is significantly larger when, at least, one of the plates is oceanic. However, the oldest oceanic plate in the Pacific ocean has the smallest convergence rate. (2) The presence of an oceanic plate is, in general, required for generation of high-magnitude (M N 8.0) earthquakes and for generating intermediate and deep seismicity along the convergent margins. When oceanic slabs subduct beneath a continent, a gap in the seismogenic zone exists at depths between ca. 250 km and 500 km. Given that the seismogenic zone terminates at ca. 200 km depth in case of continent-continent collision, we propose oceanic origin of subducting slabs beneath the Zagros, the Pamir, and the Vrancea zone. (3) Dip angle of the subducting slab in continent-ocean collision does not correlate neither with the age of subducting oceanic slab, nor with the convergence rate. For ocean-ocean subduction, clear trends are recognized: steeply dipping slabs are characteristic of young subducting plates and of oceanic plates with high convergence rate, with slab rotation towards a near-vertical dip angle at depths below ca. 500 km at very high convergence rate. (4) Local isostasy is not satisfied at the convergent margins as evidenced by strong free air gravity anomalies of positive and negative signs. However, near-isostatic equilibrium may exist in broad zones of distributed deformation such as Tibet. (5) No systematic patterns are recognized in heat flow data due to strong heterogeneity of measured values which are strongly affected by hydrothermal circulation, magmatic activity, crustal faulting, horizontal heat transfer, and also due to low number of heat flow measurements across many margins. (6) Low upper mantle Vs seismic velocities beneath the convergent margins are restricted to the upper 150 km and may be related to mantle wedge melting which is confined to shallow mantle levels. Artemieva, I.M., Thybo, H., and Shulgin, A., 2015. Geophysical constraints on geodynamic processes at convergent margins: A global perspective. Gondwana Research, http://dx.doi.org/10.1016/j.gr.2015.06.010

Marine Magnetic Data Holdings of World Data Center-a for Marine Geology and Geophysics

NASA Technical Reports Server (NTRS)

Sharman, George F.; Metzger, Dan

1992-01-01

The World Data Center-A for Marine Geology and Geophysics is co-located with the Marine Geology & Geophysical Data Center, Boulder, CO. Fifteen million digital marine magnetic trackline measurements are managed within the GEOphysical DAta System (GEODAS). The bulk of these data were collected with proton precision magnetometers under Transit Satellite navigational control. Along-track sampling averages about 1 sample per kilometer, while spatial density, a function of ship's track and survey pattern, range from 4 to 0.02 data points/sq. km. In the near future, the entire geophysical data set will be available on CD-ROM. The Marine Geology and Geophysics Division (World Data Center-A for MGG), of the National Geophysical Data Center, handles a broad spectrum of marine geophysical data, including measurements of bathymetry, magnetics, gravity, seismic reflection subbottom profiles, and side-scan images acquired by ships throughout the world's oceans. Digital data encompass the first three, while the latter two are in analog form, recorded on 35mm microfilm. The marine geophysical digital trackline data are contained in the GEODAS data base which includes 11.6 million nautical miles of cruise trackline coverage contributed by more than 70 organizations worldwide. The inventory includes data from 3206 cruises with 33 million digital records and indexing to 5.3 million track miles of analog data on microfilm.

Experiences of a Multidisciplinary Course on Geo-Signal Processing from a DSP Perspective Offered in Electrical Engineering at King Fahd University of Petroleum and Minerals

ERIC Educational Resources Information Center

Mousa, W. A.

2012-01-01

The purpose of this paper is to share the experience gained in, and the efforts made toward, introducing and implementing a new course in the challenging and important area of geophysical signal processing at the Electrical Engineering (EE) Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. The new course,…

Practical UXO Classification: Enhanced Data Processing Strategies for Technology Transition - Fort Ord: Dynamic and Cued Metalmapper Processing and Classification

DTIC Science & Technology

2017-06-06

OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for...Geophysical Mapping, Electromagnetic Induction, Instrument Verification Strip, Time Domain Electromagnetic, Unexploded Ordnance 16. SECURITY...Munitions Response QA Quality Assurance QC Quality Control ROC Receiver Operating Characteristic RTK Real- time Kinematic s Second SNR

Behavior of thermal plasma in the ionosphere and magnetosphere

NASA Technical Reports Server (NTRS)

Banks, P. M.; Doupnik, J. R.

1973-01-01

Models of ion flow in the topside ionosphere were developed. These models took both H(+) and O(+) into account and permitted various parameter studies to be made affecting H(+) escape in polar winds. Extensive computer programs were written to display the measured electron density profiles in ways useful to geophysical analysis. The relationship between the location of the plasmapause as it is found in the equatorial plane and the location of the ionospheric trough was also investigated.

Spacecraft Dynamics as Related to Laboratory Experiments in Space. [conference

NASA Technical Reports Server (NTRS)

Fichtl, G. H. (Editor); Antar, B. N. (Editor); Collins, F. G. (Editor)

1981-01-01

Proceedings are presented of a conference sponsored by the Physics and Chemistry Experiments in Space Working Group to discuss the scientific and engineering aspects involved in the design and performance of reduced to zero gravity experiments affected by spacecraft environments and dynamics. The dynamics of drops, geophysical fluids, and superfluid helium are considered as well as two phase flow, combustion, and heat transfer. Interactions between spacecraft motions and the atmospheric cloud physics laboratory experiments are also examined.

Science Data Preservation: Implementation and Why It Is Important

NASA Technical Reports Server (NTRS)

Kempler, Steven J.; Moses, John F.; Gerasimov, Irina V.; Johnson, James E.; Vollmer, Bruce E.; Theobald, Michael L.; Ostrenga, Dana M.; Ahmad, Suraiya; Ramapriyan, Hampapuram K.; Khayat, Mohammad G.

2013-01-01

Remote Sensing data generation by NASA to study Earth s geophysical processes was initiated in 1960 with the launch of the first Television Infrared Observation Satellite Program (TIROS), to develop a meteorological satellite information system. What would be deemed as a primitive data set by today s standards, early Earth science missions were the foundation upon which today s remote sensing instruments have built their scientific success, and tomorrow s instruments will yield science not yet imagined. NASA Scientific Data Stewardship requirements have been documented to ensure the long term preservation and usability of remote sensing science data. In recent years, the Federation of Earth Science Information Partners and NASA s Earth Science Data System Working Groups have organized committees that specifically examine standards, processes, and ontologies that can best be employed for the preservation of remote sensing data, supporting documentation, and data provenance information. This presentation describes the activities, issues, and implementations, guided by the NASA Earth Science Data Preservation Content Specification (423-SPEC-001), for preserving instrument characteristics, and data processing and science information generated for 20 Earth science instruments, spanning 40 years of geophysical measurements, at the NASA s Goddard Earth Sciences Data and Information Services Center (GES DISC). In addition, unanticipated preservation/implementation questions and issues in the implementation process are presented.

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.

Looking into the Earth

NASA Astrophysics Data System (ADS)

Mussett, Alan E.; Aftab Khan, M.; Button, Illustrated By Sue

2000-12-01

Looking Into the Earth comprehensively describes the principles and applications of both `global' and `exploration' geophysics on all scales. It forms an introduction to geophysics suitable for those who do not necessarily intend to become professional geophysicists, including geologists, civil engineers, environmental scientists, and field archaeologists. The book is organised into two parts: Part 1 describes the geophysical methods, while Part 2 illustrates their use in a number of extended case histories. Mathematical and physical principles are introduced at an elementary level, and then developed as necessary. Student questions and exercises are included at the end of each chapter. The book is aimed primarily at introductory and intermediate university students taking courses in geology, earth science, environmental science, and engineering. It will also form an excellent introductory textbook in geophysics departments, and will help practising geologists, archaeologists and engineers understand what geophysics can offer their work. Accessible to students with little background in maths and physics Covers both global and applied geophysics Well illustrated and contains many student exercises and case studies Written by experienced teachers of geophysics

High-Resolution Gravity and Time-Varying Gravity Field Recovery using GRACE and CHAMP

NASA Technical Reports Server (NTRS)

Shum, C. K.

2002-01-01

This progress report summarizes the research work conducted under NASA's Solid Earth and Natural Hazards Program 1998 (SENH98) entitled High Resolution Gravity and Time Varying Gravity Field Recovery Using GRACE (Gravity Recovery and Climate Experiment) and CHAMP (Challenging Mini-satellite Package for Geophysical Research and Applications), which included a no-cost extension time period. The investigation has conducted pilot studies to use the simulated GRACE and CHAMP data and other in situ and space geodetic observable, satellite altimeter data, and ocean mass variation data to study the dynamic processes of the Earth which affect climate change. Results from this investigation include: (1) a new method to use the energy approach for expressing gravity mission data as in situ measurements with the possibility to enhance the spatial resolution of the gravity signal; (2) the method was tested using CHAMP and validated with the development of a mean gravity field model using CHAMP data, (3) elaborate simulation to quantify errors of tides and atmosphere and to recover hydrological and oceanic signals using GRACE, results show that there are significant aliasing effect and errors being amplified in the GRACE resonant geopotential and it is not trivial to remove these errors, and (4) quantification of oceanic and ice sheet mass changes in a geophysical constraint study to assess their contributions to global sea level change, while the results improved significant over the use of previous studies using only the SLR (Satellite Laser Ranging)-determined zonal gravity change data, the constraint could be further improved with additional information on mantle rheology, PGR (Post-Glacial Rebound) and ice loading history. A list of relevant presentations and publications is attached, along with a summary of the SENH investigation generated in 2000.

Geophysical Properties of Hard Rock for Investigation of Stress Fields in Deep Mines

NASA Astrophysics Data System (ADS)

Tibbo, M.; Young, R. P.; Schmitt, D. R.; Milkereit, B.

2014-12-01

A complication in geophysical monitoring of deep mines is the high-stress dependency of the physical properties of hard rocks. In-mine observations show anisotropic variability of the in situ P- and S-wave velocities and resistivity of the hard rocks that are likely related to stress field changes. As part of a comprehensive study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, data from in situ monitoring of the seismicity, conductivity, stress, and stress dependent physical properties has been obtain. In-laboratory experiments are also being performed on borehole cores from the Sudbury mines. These experiments will measure the Norite borehole core's properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. Hydraulic fracturing has been successfully implemented in industries such as oil and gas and enhanced geothermal systems, and is currently being investigated as a potential method for preconditioning in mining. However, further research is required to quantify how hydraulic fractures propagate through hard, unfractured rock as well as naturally fractured rock typically found in mines. These in laboratory experiments will contribute to a hydraulic fracturing project evaluating the feasibility and effectiveness of hydraulic fracturing as a method of de-stressing hard rock mines. A tri-axial deformation cell equipped with 18 Acoustic Emission (AE) sensors will be used to bring the borehole cores to a tri-axial state of stress. The cores will then be injected with fluid until the the hydraulic fracture has propagated to the edge of the core, while AE waveforms will be digitized continuously at 10 MHz and 12-bit resolution for the duration of each experiment. These laboratory hydraulic fracture experiments will contribute to understanding how parameters including stress ratio, fluid injection rate, and viscosity, affect the fracturing process.

Geophysics of Small Planetary Bodies

NASA Technical Reports Server (NTRS)

Asphaug, Erik I.

1998-01-01

As a SETI Institute PI from 1996-1998, Erik Asphaug studied impact and tidal physics and other geophysical processes associated with small (low-gravity) planetary bodies. This work included: a numerical impact simulation linking basaltic achondrite meteorites to asteroid 4 Vesta (Asphaug 1997), which laid the groundwork for an ongoing study of Martian meteorite ejection; cratering and catastrophic evolution of small bodies (with implications for their internal structure; Asphaug et al. 1996); genesis of grooved and degraded terrains in response to impact; maturation of regolith (Asphaug et al. 1997a); and the variation of crater outcome with impact angle, speed, and target structure. Research of impacts into porous, layered and prefractured targets (Asphaug et al. 1997b, 1998a) showed how shape, rheology and structure dramatically affects sizes and velocities of ejecta, and the survivability and impact-modification of comets and asteroids (Asphaug et al. 1998a). As an affiliate of the Galileo SSI Team, the PI studied problems related to cratering, tectonics, and regolith evolution, including an estimate of the impactor flux around Jupiter and the effect of impact on local and regional tectonics (Asphaug et al. 1998b). Other research included tidal breakup modeling (Asphaug and Benz 1996; Schenk et al. 1996), which is leading to a general understanding of the role of tides in planetesimal evolution. As a Guest Computational Investigator for NASA's BPCC/ESS supercomputer testbed, helped graft SPH3D onto an existing tree code tuned for the massively parallel Cray T3E (Olson and Asphaug, in preparation), obtaining a factor xIO00 speedup in code execution time (on 512 cpus). Runs which once took months are now completed in hours.

Boise Hydrogeophysical Research Site: Control Volume/Test Cell and Community Research Asset

NASA Astrophysics Data System (ADS)

Barrash, W.; Bradford, J.; Malama, B.

2008-12-01

The Boise Hydrogeophysical Research Site (BHRS) is a research wellfield or field-scale test facility developed in a shallow, coarse, fluvial aquifer with the objectives of supporting: (a) development of cost- effective, non- or minimally-invasive quantitative characterization and imaging methods in heterogeneous aquifers using hydrologic and geophysical techniques; (b) examination of fundamental relationships and processes at multiple scales; (c) testing theories and models for groundwater flow and solute transport; and (d) educating and training of students in multidisciplinary subsurface science and engineering. The design of the wells and the wellfield support modular use and reoccupation of wells for a wide range of single-well, cross-hole, multiwell and multilevel hydrologic, geophysical, and combined hydrologic-geophysical experiments. Efforts to date by Boise State researchers and collaborators have been largely focused on: (a) establishing the 3D distributions of geologic, hydrologic, and geophysical parameters which can then be used as the basis for jointly inverting hard and soft data to return the 3D K distribution and (b) developing subsurface measurement and imaging methods including tomographic characterization and imaging methods. At this point the hydrostratigraphic framework of the BHRS is known to be a hierarchical multi-scale system which includes layers and lenses that are recognized with geologic, hydrologic, radar, seismic, and EM methods; details are now emerging which may allow 3D deterministic characterization of zones and/or material variations at the meter scale in the central wellfield. Also the site design and subsurface framework have supported a variety of testing configurations for joint hydrologic and geophysical experiments. Going forward we recognize the opportunity to increase the R&D returns from use of the BHRS with additional infrastructure (especially for monitoring the vadose zone and surface water-groundwater interactions), more collaborative activity, and greater access to site data. Our broader goal of becoming more available as a research asset for the scientific community also supports the long-term business plan of increasing funding opportunities to maintain and operate the site.

Geophysical Investigation of Buried Slag at the Parrot Tailings Site, Butte, Montana

NASA Astrophysics Data System (ADS)

Ha, C. D. M.; Shepherd, K.; Mack, A.; Rutherford, B. S.; Speece, M. A.

2016-12-01

Butte, Montana, has served as an important mining district for more than 120 years. This area contains historic mine waste from decades of unregulated mining practices. In July 1881, the Parrot smelter in Butte started operations and was soon processing ore and producing copper. The Parrot smelter also had a concentrating plant that treated the ore prior to smelting. The Parrot smelter wastes (slag and tailings) were later covered with Berkeley Pit crushed quartz monzonite overburden. The slag is bricked because it was deposited hot and, as a consequence forms a laterally extensive, cohesive, hard body that is difficult to remove without blasting. With the mine waste being covered by unknown quantities of overburden and soil throughout the area, and core data being limited and expensive to retrieve, the only economical method of discovery is geophysics. Several geophysical techniques were used to determine the lateral boundaries and depth of the buried slag body. The geophysical methods used were seismic, gravity, electromagnetic induction, and magnetics. Not all of these geophysical surveys produced useful results due to the nature of the slag. For instance, electromagnetic induction could not distinguish between the slag and adjacent tailings; and, the microgravity profiles showed only a small gravitational field variation caused by the density contrast between slag and the surrounding tailings, sediment and granitic cover. On the other hand, the seismic surveys resulted in unexpected first arrival times that distinctly showed velocity variations due to the slag. In addition, the slag body produced a large magnetic response. Unpublished, proprietary well data allowed us to model the slag body from our magnetic data. This model was confirmed by projecting velocity tomograms, that we created using seismic diving waves, onto our magnetic models. Model results were combined to form a three-dimensional image of the slag body. These results will be used to help construct a remediation plan to remove the slag along with the associated tailings.

The Run-up to Volcanic Eruption Unveiled by Forensic Petrology and Geophysical Observations

NASA Astrophysics Data System (ADS)

Rasmussen, D. J.; Plank, T. A.; Roman, D. C.

2017-12-01

Volcanoes often warn of impending eruptions. However, one of the greatest challenges in volcano research is translating precursory geophysical signals into physical magmatic processes. Petrology offers powerful tools to study eruption run-up that benefit from direct response to magmatic forcings. Developing these tools, and tying them to geophysical observations, will help us identify eruption triggers (e.g., magmatic recharge, gas build-up, tectonic events) and understand the significance of monitored signals of unrest. We present an overview of petrologic tools used for studying eruption run-up, highlighting results from our study of the 1999 eruption of Shishaldin volcano. Olivine crystals contain chemical gradients, the consequence of diffusion following magma mixing events, which is modeled to determine mixing timescales. Modeled timescales provide strong evidence for at least three mixing events, which were triggered by magmatic recharge. Petrologic barometers indicate these events occurred at very shallow depths (within the volcanic edifice). The first mixing event occurred nine months before eruption, which was signaled by a swarm of deep-long period earthquake. Minor recharge events followed over two months, which are indicated by a second deep-long period earthquake swarm and a change in the local stress orientation measured by shear-wave splitting. Following these events, the system was relatively quiet until a large mixing event occurred 45 days prior to eruption, which was heralded by a large earthquake (M5.2). Following this event, geophysical signals of unrest intensified and became continuous. The final mixing event, beginning roughly a week before eruption, represents the final perturbation to the system before eruption. Our findings point to a relatively long run-up, which was subtle at first and intensified several weeks before eruption. This study highlights the strong link between geophysical signals of volcanic unrest and magmatic events, and helps open the door for the application of forensic petrology to unmonitored eruptions.

Interior Structure and Habitability of Ocean Worlds

NASA Astrophysics Data System (ADS)

Vance, S.; Bills, B. G.; Cammarano, F.; Panning, M. P.; Stähler, S. C.

2016-12-01

Earth's habitability depends critically on its interior structure and dynamics. Global redox cycles rely on Earth's mantle for continued flux of reduced materials (e.g., Hayes and Waldbauer 2006). Similarly, the habitability of ocean worlds must be understood in terms of their interior structure and evolution (Zolotov and Shock 2004, Hand et al. 2009, Nimmo and Pappalardo 2016, Vance et al. 2016). Combined seismology, gravity, and magnetic investigations may be able to distinguish between a hot active interior and a cold dead one. To evaluate such investigations, we are developing detailed models of interior density, elastic and anelastic structure, and associated seismic sources and signatures, building on prior work (Cammarano et al. 2006). We will present self-consistent 1-D structural models for ocean world interiors that use available thermodynamic data for fluids, ices, and rocks. Cammarano, F., V. Lekic, M. Manga, M. Panning, and B. Romanowicz (2006). Long-period seismology on Europa: 1. Physically consistent interior models. Journal of Geophysical Research, E12009:doi:10.1029/2006JE002710. Hand, K. P., C. Chyba, J. Priscu, R. Carlson, and K. Nealson (2009). Astrobiology and the Potential for Life on Europa, page 589. Arizona University Press. Hayes, J. M. and J. R. Waldbauer (2006). The carbon cycle and associated redox processes through time. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1470):931-950. Nimmo, F. and R. T. Pappalardo (2016). Ocean Worlds in the Outer Solar System. Journal of Geophysical Research, doi:10.1002/2016JE005081 Vance, S. D., K. P. Hand, and R. T. Pappalardo (2016). Geophysical controls of chemical disequilibria in Europa. Geophysical Research Letters, doi:10.1002/2016GL068547. Zolotov, M. Y. and E. L. Shock (2004). A model for low-temperature biogeochemistry of sulfur, carbon, and iron on Europa. Journal of Geophysical Research-Planets, 109(E6):E06003.

Smartphones - the Geophysics Lab in Your Students' Pocket

NASA Astrophysics Data System (ADS)

Salaree, A.; Stein, S.; Saloor, N.; Elling, R. P.

2017-12-01

Many interesting topics are hard to demonstrate in geophysics classes without costly equipment and logistic hassles. For instance, the speed of P-waves in the Earth's crust is usually calculated using printed seismic sections from published studies, giving students little insight into the recording process. This is mainly due to the complex, costly, and weather-dependent logistics of conducting seismic reflection experiments using arrays of - either purchased or borrowed - expensive seismometers and recording units. Smartphones, which students own and are (perhaps unduly) comfortable with, have many otherwise expensive instruments as built-in sensors. These instruments are nifty tools that make labs easier, faster, and more fun. We use smartphones in several labs in an introductory geophysics class. In one, students use their phones to measure the latitude and longitude of a point on campus. Combining the data shows a nice spread of positions illustrating the precision of measurements, spatial trends in the scatter, and even differences between Android and iPhone data. Hence concepts about data that are often presented with ideal theoretical examples emerge from the students' measurements. Another uses the phones' accelerometers and available software to measure the speed of P-waves using a linear array of smartphones/seismometers along a table, similar to the procedure used in reflection seismology. In a third, students used their smartphones in an elevator to measure the acceleration of gravity in a moving reference frame, and thus explore key concepts that arise in many geophysical applications. These three applications illustrate the potential for using smartphones in a wide variety of geophysics teaching, much as their value is being increasingly recognized in other educational applications. Here are some links to an instructions document and a video from the seismic experiment: Instructions: http://www.earth.northwestern.edu/ amir/202/smartphone_array.pdf Video: https://youtu.be/SL5dr4o5oTI

Transition probability-based stochastic geological modeling using airborne geophysical data and borehole data

NASA Astrophysics Data System (ADS)

He, Xin; Koch, Julian; Sonnenborg, Torben O.; Jørgensen, Flemming; Schamper, Cyril; Christian Refsgaard, Jens

2014-04-01

Geological heterogeneity is a very important factor to consider when developing geological models for hydrological purposes. Using statistically based stochastic geological simulations, the spatial heterogeneity in such models can be accounted for. However, various types of uncertainties are associated with both the geostatistical method and the observation data. In the present study, TProGS is used as the geostatistical modeling tool to simulate structural heterogeneity for glacial deposits in a head water catchment in Denmark. The focus is on how the observation data uncertainty can be incorporated in the stochastic simulation process. The study uses two types of observation data: borehole data and airborne geophysical data. It is commonly acknowledged that the density of the borehole data is usually too sparse to characterize the horizontal heterogeneity. The use of geophysical data gives an unprecedented opportunity to obtain high-resolution information and thus to identify geostatistical properties more accurately especially in the horizontal direction. However, since such data are not a direct measurement of the lithology, larger uncertainty of point estimates can be expected as compared to the use of borehole data. We have proposed a histogram probability matching method in order to link the information on resistivity to hydrofacies, while considering the data uncertainty at the same time. Transition probabilities and Markov Chain models are established using the transformed geophysical data. It is shown that such transformation is in fact practical; however, the cutoff value for dividing the resistivity data into facies is difficult to determine. The simulated geological realizations indicate significant differences of spatial structure depending on the type of conditioning data selected. It is to our knowledge the first time that grid-to-grid airborne geophysical data including the data uncertainty are used in conditional geostatistical simulations in TProGS. Therefore, it provides valuable insights regarding the advantages and challenges of using such comprehensive data.

The Role of Anchor Stations in the Validation of Earth Observation Satellite Data and Products. The Valencia and the Alacant Anchor Stations

NASA Astrophysics Data System (ADS)

Lopez-Baeza, Ernesto; Geraldo Ferreira, A.; Saleh-Contell, Kauzar

Space technology facilitates humanity and science with a global revolutionary view of the Earth through the acquisition of Earth Observation satellite data. Satellites capture information over different spatial and temporal scales and assist in understanding natural climate processes and in detecting and explaining climate change. Accurate Earth Observation data is needed to describe climate processes by improving the parameterisations of different climate elements. Algorithms to produce geophysical parameters from raw satellite observations should go through selection processes or participate in inter-comparison programmes to ensure performance reliability. Geophysical parameter datasets, obtained from satellite observations, should pass a quality control before they are accepted in global databases for impact, diagnostic or sensitivity studies. Calibration and Validation, or simply "Cal/Val", is the activity that endeavours to ensure that remote sensing products are highly consistent and reproducible. This is an evolving scientific activity that is becoming increasingly important as more long-term studies on global change are undertaken, and new satellite missions are launched. Calibration is the process of quantitatively defining the system responses to known, controlled signal inputs. Validation refers to the process of assessing, by independent means, the quality of the data products derived from the system outputs. These definitions are generally accepted and most often used in the remote sensing context to refer specifically and respectively to sensor radiometric calibration and geophysical parameter validation. Anchor Stations are carefully selected locations at which instruments measure quantities that are needed to run, calibrate or validate models and algorithms. These are needed to quanti-tatively evaluate satellite data and convert it into geophysical information. The instruments collect measurements of basic quantities over a long timescale. Measurements are made of meteorological and hydrological background data, and of quantities not readily assessed at operational stations. Anchor Stations also offer infrastructure to undertake validation experi-ments. These are more detailed measurements over shorter intensive observation periods. The Valencia Anchor Station is showing its capabilities and conditions as a reference validation site in the framework of low spatial resolution remote sensing missions such as CERES, GERB and SMOS. The Alacant Anchor Station is a reference site in studies on the interactions between desertification and climate. This paper presents the activities so far carried out at both Anchor Stations, the precise and detailed ground and aircraft experiments carefully designed to develop a specific methodology to validate low spatial resolution satellite data and products, and the knowledge exchange currently being exercised between the University of Valencia, Spain, and FUNCEME, Brazil, in common objectives of mutual interest.

Ground penetrating radar detection of subsnow slush on ice-covered lakes in interior Alaska

NASA Astrophysics Data System (ADS)

Gusmeroli, A.; Grosse, G.

2012-12-01

Lakes are abundant throughout the pan-Arctic region. For many of these lakes ice cover lasts for up to two thirds of the year. The frozen cover allows human access to these lakes, which are therefore used for many subsistence and recreational activities, including water harvesting, fishing, and skiing. Safe traveling condition onto lakes may be compromised, however, when, after significant snowfall, the weight of the snow acts on the ice and causes liquid water to spill through weak spots and overflow at the snow-ice interface. Since visual detection of subsnow slush is almost impossible our understanding on overflow processes is still very limited and geophysical methods that allow water and slush detection are desirable. In this study we demonstrate that a commercially available, lightweight 1 GHz, ground penetrating radar system can detect and map extent and intensity of overflow. The strength of radar reflections from wet snow-ice interfaces are at least twice as much in strength than returns from dry snow-ice interface. The presence of overflow also affects the quality of radar returns from the base of the lake ice. During dry conditions we were able to profile ice thickness of up to 1 m, conversely, we did not retrieve any ice-water returns in areas affected by overflow.

A Review of High-Performance Computational Strategies for Modeling and Imaging of Electromagnetic Induction Data

NASA Astrophysics Data System (ADS)

Newman, Gregory A.

2014-01-01

Many geoscientific applications exploit electrostatic and electromagnetic fields to interrogate and map subsurface electrical resistivity—an important geophysical attribute for characterizing mineral, energy, and water resources. In complex three-dimensional geologies, where many of these resources remain to be found, resistivity mapping requires large-scale modeling and imaging capabilities, as well as the ability to treat significant data volumes, which can easily overwhelm single-core and modest multicore computing hardware. To treat such problems requires large-scale parallel computational resources, necessary for reducing the time to solution to a time frame acceptable to the exploration process. The recognition that significant parallel computing processes must be brought to bear on these problems gives rise to choices that must be made in parallel computing hardware and software. In this review, some of these choices are presented, along with the resulting trade-offs. We also discuss future trends in high-performance computing and the anticipated impact on electromagnetic (EM) geophysics. Topics discussed in this review article include a survey of parallel computing platforms, graphics processing units to multicore CPUs with a fast interconnect, along with effective parallel solvers and associated solver libraries effective for inductive EM modeling and imaging.

Parts-based geophysical inversion with application to water flooding interface detection and geological facies detection

NASA Astrophysics Data System (ADS)

Zhang, Junwei

I built parts-based and manifold based mathematical learning model for the geophysical inverse problem and I applied this approach to two problems. One is related to the detection of the oil-water encroachment front during the water flooding of an oil reservoir. In this application, I propose a new 4D inversion approach based on the Gauss-Newton approach to invert time-lapse cross-well resistance data. The goal of this study is to image the position of the oil-water encroachment front in a heterogeneous clayey sand reservoir. This approach is based on explicitly connecting the change of resistivity to the petrophysical properties controlling the position of the front (porosity and permeability) and to the saturation of the water phase through a petrophysical resistivity model accounting for bulk and surface conductivity contributions and saturation. The distributions of the permeability and porosity are also inverted using the time-lapse resistivity data in order to better reconstruct the position of the oil water encroachment front. In our synthetic test case, we get a better position of the front with the by-products of porosity and permeability inferences near the flow trajectory and close to the wells. The numerical simulations show that the position of the front is recovered well but the distribution of the recovered porosity and permeability is only fair. A comparison with a commercial code based on a classical Gauss-Newton approach with no information provided by the two-phase flow model fails to recover the position of the front. The new approach could be also used for the time-lapse monitoring of various processes in both geothermal fields and oil and gas reservoirs using a combination of geophysical methods. A paper has been published in Geophysical Journal International on this topic and I am the first author of this paper. The second application is related to the detection of geological facies boundaries and their deforation to satisfy to geophysica data and prior distributions. We pose the geophysical inverse problem in terms of Gaussian random fields with mean functions controlled by petrophysical relationships and covariance functions controlled by a prior geological cross-section, including the definition of spatial boundaries for the geological facies. The petrophysical relationship problem is formulated as a regression problem upon each facies. The inversion is performed in a Bayesian framework. We demonstrate the usefulness of this strategy using a first synthetic case study, performing a joint inversion of gravity and galvanometric resistivity data with the stations all located at the ground surface. The joint inversion is used to recover the density and resistivity distributions of the subsurface. In a second step, we consider the possibility that the facies boundaries are deformable and their shapes are inverted as well. We use the level set approach to deform the facies boundaries preserving prior topological properties of the facies throughout the inversion. With the additional help of prior facies petrophysical relationships, topological characteristic of each facies, we make posterior inference about multiple geophysical tomograms based on their corresponding geophysical data misfits. The result of the inversion technique is encouraging when applied to a second synthetic case study, showing that we can recover the heterogeneities inside the facies, the mean values for the petrophysical properties, and, to some extent, the facies boundaries. A paper has been submitted to Geophysics on this topic and I am the first author of this paper. During this thesis, I also worked on the time lapse inversion problem of gravity data in collaboration with Marios Karaoulis and a paper was published in Geophysical Journal international on this topic. I also worked on the time-lapse inversion of cross-well geophysical data (seismic and resistivity) using both a structural approach named the cross-gradient approach and a petrophysical approach. A paper was published in Geophysics on this topic.

3-D Characterization of Seismic Properties at the Smart Weapons Test Range, YPG

NASA Astrophysics Data System (ADS)

Miller, Richard D.; Anderson, Thomas S.; Davis, John C.; Steeples, Don W.; Moran, Mark L.

2001-10-01

The Smart Weapons Test Range (SWTR) lies within the Yuma Proving Ground (YPG), Arizona. SWTR is a new facility constructed specifically for the development and testing of futuristic intelligent battlefield sensor networks. In this paper, results are presented for an extensive high-resolution geophysical characterization study at the SWTR site along with validation using 3-D modeling. In this study, several shallow seismic methods and novel processing techniques were used to generate a 3-D grid of earth seismic properties, including compressional (P) and shear (S) body-wave speeds (Vp and Vs), and their associated body-wave attenuation parameters (Qp, and Qs). These experiments covered a volume of earth measuring 1500 m by 300 m by 25 m deep (11 million cubic meters), centered on the vehicle test track at the SWTR site. The study has resulted in detailed characterizations of key geophysical properties. To our knowledge, results of this kind have not been previously achieved, nor have the innovative methods developed for this effort been reported elsewhere. In addition to supporting materiel developers with important geophysical information at this test range, the data from this study will be used to validate sophisticated 3-D seismic signature models for moving vehicles.

Reservoir and Source Rock Identification Based on Geologycal, Geophysics and Petrophysics Analysis Study Case: South Sumatra Basin

NASA Astrophysics Data System (ADS)

Anggit Maulana, Hiska; Haris, Abdul

2018-05-01

Reservoir and source rock Identification has been performed to deliniate the reservoir distribution of Talangakar Formation South Sumatra Basin. This study is based on integrated geophysical, geological and petrophysical data. The aims of study to determine the characteristics of the reservoir and source rock, to differentiate reservoir and source rock in same Talangakar formation, to find out the distribution of net pay reservoir and source rock layers. The method of geophysical included seismic data interpretation using time and depth structures map, post-stack inversion, interval velocity, geological interpretations included the analysis of structures and faults, and petrophysical processing is interpret data log wells that penetrating Talangakar formation containing hydrocarbons (oil and gas). Based on seismic interpretation perform subsurface mapping on Layer A and Layer I to determine the development of structures in the Regional Research. Based on the geological interpretation, trapping in the form of regional research is anticline structure on southwest-northeast trending and bounded by normal faults on the southwest-southeast regional research structure. Based on petrophysical analysis, the main reservoir in the field of research, is a layer 1,375 m of depth and a thickness 2 to 8.3 meters.

Dust deposition and ambient PM10 concentration in northwest China: Spatial and temporal variability

USDA-ARS?s Scientific Manuscript database

Aeolian dust transport and deposition are important geophysical processes which influence global bio-geochemical cycles. Currently, reliable continental deposition data are scarce in central Asia. Located in the eastern part of central Asia, Xinjiang Province of northwestern China has long played a ...

Major Martian Volcanoes from MOLA - Alba Patera

NASA Technical Reports Server (NTRS)

2000-01-01

Two views of Alba Patera with topography draped over a Viking image mosaic. MOLA data have clarified the relationship between fault location and topography on and surrounding the Alba construct, providing insight into the volcanological and geophysical processes that shaped the edifice. The vertical exaggeration is 10:1.

The Effect of Atomic Oxygen on POSS-Polyimides (Preprint)

DTIC Science & Technology

2008-05-01

Symposium and Exhibition sponsored by the Society for the Advancement of Materials and Process Engineering, Long Beach, CA, May 12-16, 2002. 6. Koontz ...and Incoherent-Scatter Data - Msis-83," Journal of Geophysical Research-Space Physics, 1983, 88(A12), 170-188. 21. Koontz , S.L., Leger, L. J

Preface: Subsurface, surface and atmospheric processes in cold regions hydrology

USDA-ARS?s Scientific Manuscript database

This special section presents papers from three sessions at the 24th General Assembly of the International Union of Geodesy and Geophysics (IUGG), held in Perugia, Italy, in July 2007: ‘Interactions between snow, vegetation and the atmosphere’, ‘Hydrology in mountain regions’ and ‘Climate-permafrost...

Multi-array borehole resistivity and induced polarization method with mathematical inversion of redundant data

DOEpatents

Ward, S.H.

1989-10-17

Multiple arrays of electric or magnetic transmitters and receivers are used in a borehole geophysical procedure to obtain a multiplicity of redundant data suitable for processing into a resistivity or induced polarization model of a subsurface region of the earth. 30 figs.

Integrating Multiple Geophysical Methods to Quantify Alpine Groundwater- Surface Water Interactions: Cordillera Blanca, Peru

NASA Astrophysics Data System (ADS)

Glas, R. L.; Lautz, L.; McKenzie, J. M.; Baker, E. A.; Somers, L. D.; Aubry-Wake, C.; Wigmore, O.; Mark, B. G.; Moucha, R.

2016-12-01

Groundwater- surface water interactions in alpine catchments are often poorly understood as groundwater and hydrologic data are difficult to acquire in these remote areas. The Cordillera Blanca of Peru is a region where dry-season water supply is increasingly stressed due to the accelerated melting of glaciers throughout the range, affecting millions of people country-wide. The alpine valleys of the Cordillera Blanca have shown potential for significant groundwater storage and discharge to valley streams, which could buffer the dry-season variability of streamflow throughout the watershed as glaciers continue to recede. Known as pampas, the clay-rich, low-relief valley bottoms are interfingered with talus deposits, providing a likely pathway for groundwater recharged at the valley edges to be stored and slowly released to the stream throughout the year by springs. Multiple geophysical methods were used to determine areas of groundwater recharge and discharge as well as aquifer geometry of the pampa system. Seismic refraction tomography, vertical electrical sounding (VES), electrical resistivity tomography (ERT), and horizontal-to-vertical spectral ratio (HVSR) seismic methods were used to determine the physical properties of the unconsolidated valley sediments, the depth to saturation, and the depth to bedrock for a representative section of the Quilcayhuanca Valley in the Cordillera Blanca. Depth to saturation and lithological boundaries were constrained by comparing geophysical results to continuous records of water levels and sediment core logs from a network of seven piezometers installed to depths of up to 6 m. Preliminary results show an average depth to bedrock for the study area of 25 m, which varies spatially along with water table depths across the valley. The conceptual model of groundwater flow and storage derived from these geophysical data will be used to inform future groundwater flow models of the area, allowing for the prediction of groundwater resources for the region in the absence of glacial meltwater.

A multidisciplinary approach for the characterisation of fault zones in geothermal areas in central Mexico

NASA Astrophysics Data System (ADS)

Comina, Cesare; Ferrero, Anna Maria; Mandrone, Giuseppe; Vinciguerra, Sergio

2017-04-01

There are more than 500 geothermal areas in the Trans-Mexican Volcanic Belt of central Mexico. Of these, two are presently object of a transnational project between EU and Mexico (GEMex): Acoculco, where there is already a commercial exploitation, and Los Humeros, at present not developed yet. The GEMex project aims to improve the resource assessment and the reservoir characterization using novel geophysical and geological methods and interpretations. One of the main issues controlling the geothermal system is the presence of pervasive fracture systems affecting the carbonatic basements underlying the volcanic complex (basalts and andesites). We propose the characterization of rock masses (rock and fractures) using a multiscale analysis, from the field to the outcrop up to the micro scale integrating a number of techniques. In detail, the University of Torino unit will take care of: 1) Technical field studies aimed to the characterization of the mechanical transitions throughout brittle deformation zones, from the intact rock, to the damage zone to the shear/slip zone; moreover, key geophysical parameters (seismic and electrical properties) will be measured; 2) Petrophysical and minero-petrographic detailed studies on representative samples will be performed at room temperature; verification of the mechanical properties of the samples subjected to cycles of heating up to the temperatures of the reservoir (> 400 °C) will be done; measurements of the geophysical properties of the samples will be done in comparison with the measures in place. 3) Numerical modeling to estimate the petrophysical, geophysical and geomechanical properties of the rock mass under the P and T conditions of the reservoir (i.e., using Comsol, VGeST, UDEC, 3DEC, ...). Detailed geological field studies and photogrammetry/laser scanner imaging of studied outcrops are supposed to be available soon: multiscale analysis will benefis from these new data. Results will be shared between EU and Mexican partners to improve the general model of these two geothermal field.

Turning Equations Into Stories: Using "Equation Dictionaries" in an Introductory Geophysics Class

NASA Astrophysics Data System (ADS)

Caplan-Auerbach, J.

2008-12-01

To students with math fear, equations can be intimidating and overwhelming. This discomfort is reflected in some of the frequent questions heard in introductory geophysics: "which equation should I use?" and "does T stand for travel time or period?" Questions such as these indicate that many students view equations as a series of variables and operators rather than as a representation of a physical process. To solve a problem they may simply look for an equation with the correct variables and assume that it meets their needs, rather than selecting an equation that represents the appropriate physical process. These issues can be addressed by encouraging students to think of equations as stories, and to describe them in prose. This is the goal of the Equation Dictionary project, used in Western Washington University's introductory geophysics course. Throughout the course, students create personal equation dictionaries, adding an entry each time an equation is introduced. Entries consist of (a) the equation itself, (b) a brief description of equation variables, (c) a prose description of the physical process described by the equation, and (d) any additional notes that help them understand the equation. Thus, rather than simply writing down the equations for the velocity of body waves, a student might write "The speed of a seismic body wave is controlled by the material properties of the medium through which it passes." In a study of gravity a student might note that the International Gravity Formula describes "the expected value of g at a given latitude, correcting for Earth's shape and rotation." In writing these definitions students learn that equations are simplified descriptions of physical processes, and that understanding the process is more useful than memorizing a sequence of variables. Dictionaries also serve as formula sheets for exams, which encourages students to write definitions that are meaningful to them, and to organize their thoughts clearly. Finally, instructor review of the dictionaries is an excellent way to identify student misconceptions and learn how well they understand derivations and lectures.

Young Geophysicists: `Know How' Tips to Nourish Them from Lectures and Seminars to Field Work and Conferences (Geology and Geophysics Department, Novosibirsk State University, GGD, NSU).

NASA Astrophysics Data System (ADS)

Rakhmenkulova, I. F.

2016-12-01

How to nourish young brilliant geophysicists? Here are the tips: We teach them as physicists (at the Department of Physics, together with students majoring in physics). Students have special facilities in field work, using most modern geophysical equipment. They can participate in real projects on applied geophysics during their studies. They attend special seminars and conferences for both young professionals and full-fledged scientists. Their English Language Program is focused on geophysical terminology. There are four specialties at Geology and Geophysics Department of Novosibirsk State University: Geophysics, Geochemistry, Geology, and Geochemistry of Oil and Gas. However, the curriculum for geophysicists is absolutely different from other specialties. Mathematics, physics and laboratory work are given at the Department of Physics (together with students majoring in physics). All the necessary geological subjects are also studied (including field work). During all period of their study the students work part time at many geophysical institutions. The equipment is both traditional and most modern, created at the Institute of Oil and Gas Geophysics. The students present the result of their field work and laboratory experiments in many seminars and conferences. For example, there is a traditional annual conference in Shira, Khakassia, for young professionals. Every year the Seminar in Geodynamics, Geophysics and Geomechanics is held in the Altay Mountains (Denisova Cave Camp). This Seminar was organized by the late Sergey Goldin, the Director of the Institute of Geophysics, the Head of the Chair of Geophysics, a Member of the Russian Academy of Sciences. In July 2016 this Seminar was devoted to 80's birth anniversary of Sergey Goldin. Several students of geophysics presented the results of their work there. Next year the seminar is supposed to be international. A special attention is given to the English course lasting for 5 years. The students learn general English at first, but then their study is focused on English for geophysicists, including special terminology. This is done for successful integration of young geophysicists into international professional community. Many GGD students are members of international professional organizations, such as SEG, SPE, AGU and others.

Investigation of subrosion processes using an integrated geophysical approach

NASA Astrophysics Data System (ADS)

Miensopust, Marion; Hupfer, Sarah; Kobe, Martin; Schneider-Löbens, Christiane; Wadas, Sonja

2017-04-01

Subrosion, i.e., leaching of readily soluble rocks, is usually of natural origin but can be enhanced by anthropogenic interferences. In recent years, public awareness of subrosion processes in terms of the in parts catastrophic implications and incidences increased. Especially the sinkholes in Schmalkalden, Tiefenort and Nordhausen (Germany) are three dramatic examples. They show that the knowledge of those processes and therefore, the predictability of such events is insufficient. The complexity of subrosion processes requires an integrated geophysical approach, which investigates the interlinking of structure, hydraulics, leaching, and mechanics. This contributes to a better understanding of the processes by reliable imaging and characterisation of subrosion structures. At LIAG an inter-sectional group is engaged in geophysical investigation of subrosion processes. The focus is application, enhancement and combination of various geophysical methods both at surface and in boreholes. This includes the monitoring of surface deformation and the application of time-lapse gravity as well as seismic, geoelectric and electromagnetic methods. Petrophysical investigations (with focus on Spectral Induced Polarisation - SIP) are conducted to characterise the processes on pore scale. Numerical studies are applied to advance the understanding of void forming processes and the mechanical consequences in the dynamic interaction. Since March 2014, quarterly campaigns are conducted to monitor changes in gravity acceleration at 15 stations in the urban area of Bad Frankenhausen. The standard deviations of the adjusted gravity differences are in the single-digit µGal range. The gravity acceleration changes in the range of 0 to 15 µGal over a timespan of three years and the accompanying levelling locally shows continuous subsidence in the mm/year-range. Sixteen SH-wave and four P-wave reflection seismic profiles together with three VSṔs were surveyed in the city of Bad Frankenhausen. Additionally, five SH-wave profiles and one VSP were carried out around the sinkhole of Schmalkalden. The underground in the local subrosion areas is heterogeneous with many fractures and faults. Subrosion structures were imaged in high-resolution and by defining the shear-modulus. Vp/Vs-ratio unstable areas have been identified. Electric and electromagnetic methods have been used to investigate the geological structure of a karst system based on the different bulk resistivities of the various geological units and reflections of electromagnetic waves at interfaces. The borehole georadar has been used to detect a cavity and areas of disruption. Different types of carbonates were analysed with laboratory SIP-measurements. First results show polarisation effects for all carbonate types. Four different phase behaviours were observed in the phase spectra. Further experiments will be conducted to get more insight into the phase behaviour of carbonates. Numerical modelling is applied to simulate the collapse mechanism and rock failure to specify the conditions in which sinkholes form. Important parameters for failure are thickness of overburden, lateral dimension and shape of the cavity, existing fracture network and layer boundaries, which partly can be provided by the other methods. This diversity of methods allows a characterisation of karst systems and subrosion structures based on various complementary properties and on many scales from pore size to the big picture of the karst system.

High-Resolution geophysical data from the inner continental shelf at Vineyard Sound, Massachusetts

USGS Publications Warehouse

Andrews, Brian D.; Ackerman, Seth D.; Baldwin, Wayne E.; Foster, David S.; Schwab, William C.

2013-01-01

The U.S. Geological Survey (USGS) and the Massachusetts Office of Coastal Zone Management (CZM) have mapped approximately 340 square kilometers of the inner continental shelf in Vineyard Sound, Massachusetts, under a cooperative mapping program. The geophysical data collected between 2009 and 2011 by the U.S. Geological Survey as part of this program are published in this report. The data include (1) swath bathymetry from interferometric sonar, (2) acoustic backscatter from sidescan sonar, and (3) seismic-reflection profiles from a chirp subbottom profiler. These data were collected to support research on the influence of sea-level change and sediment supply on coastal evolution and sediment transport processes and to provide baseline seabed characterization information required for management of coastal and offshore resources within the coastal zone of Massachusetts.

A satellite-based digital data system for low-frequency geophysical data

USGS Publications Warehouse

Silverman, S.; Mortensen, C.; Johnston, M.

1989-01-01

A reliable method for collection, display, and analysis of low-frequency geophysical data from isolated sites, which can be throughout North and South America and the Pacific Rim, has been developed for use with the Geostationary Operational Environmental Satellite (GEOS) system. This system provides real-time monitoring of crustal deformation parameters such as tilt, strain, fault displacement, local magnetic field, crustal geochemistry, and water levels, as well as meteorological and other parameters, along faults in California and Alsaka, and in volcanic regions in the western United States, Rabaul, and other locations in the New Britain region of the South pacific. Various mathematical, statistical, and graphical algorithms process the incoming data to detect changes in crustal deformation and fault slip that may indicate the first stages of catastrophic fault failure. -from Authors

Publications - SR 51 | Alaska Division of Geological & Geophysical Surveys

Science.gov Websites

& Geophysical Surveys Comments: Your help is crucial in the compilation of future Alaska Minerals Resources; Fluorine; Geophysics; Germanium; Gold; Heap Leach; Iron; Jade; Lead; Lode; Mercury; Minerals

Publications - NL 2006-1 | Alaska Division of Geological & Geophysical

Science.gov Websites

Liberty Bell, western Bonnifield mining district geophysical tract Authors: DGGS Staff, and Athey, J.E inventory Liberty Bell, western Bonnifield mining district geophysical tract: Alaska Division of Geological