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Application of the magnetotelluric impedance tensor to earthquake prediction research in Greece
53A 892014 Application of the magnetoteiluric impedance tensor to earthquake prediction research in Greece Chouliaris, G; Rasmussen, T M
Tectonophysies V152. NI/2. 10 Sept 1988, P119-135 Two magnetoteiluric stations were installed in Greece to monitor short period measurements. Estimation of the impedance tensor elements described the local magnetotelluric induction accurately. The residual electric field was determined and used in an attempt to detect precursory seismic electric signals (SES). Results show the method to be successful in resolving ambiguities about the nature of the reported SES. Analysis of the data showed that in 2 cases sources could not be related to earthquake processes, whilst in the other 3, the source of the suspected SES, although electric, could not be established with certainty. For earthquakes of small magnitude or large epicentral distance, detection of SES is extremely difficult.
solution of the governing equations by analytical, numerical, finite difference, finite element and boundary element approaches. Collection of data for model input and verification is discussed, including soil physical properties, spatial variation and scaling, soil water content and evapotranspiration. Simulation model extension to preferential flow and hysteresis is introduced, and 4 examples presented. 146 rcfs. 892018 Contaminant hydrogeology - dollars and sense Schwartz, F W
J Hydrol VIO0. NI-3, July 1988, P453-470 There has been a growth in interest in hydrogeology due to problems of groundwater contamination and waste (especially nuclear) disposal. Important developments, including direct and indirect methods for plume definition, measurements in deep boreholes, theoretical analysis and fractured rock hydrology, are discussed. Trends for the future are considered.
Frost action, permafrost and frozen ground Groundwater See a~o: 892099. 892135 892015 Two case histories of major frost heaving in refrigerated buildings: thermal analyses, repairs, and prevention Chapuis, R P Can Geotech J V25, N3. Aug 1988, P535-540 Frost action in soils is a complex phenomenon resulting from freezing of pore water and formation and growth of ice lenses. Two case studies in which frost penetration into soils underlying concrete slabs caused vertical expansion are presented. Thermal analysis was performed using a frost penetration equation for a muhilayered system with latent heat. Theoretical progression of the frost line and repair solutions are considered. 892016 Freeze-thaw effects on granular structure reorganization for soil materials of varying texture and moisture content Pawluk, S Can J Soil Sci V68. N3, Aug 1988. P485-494 Experiments were undertaken to determine whether microfabrics could be produced in soils using freeze-thaw. Undisturbed cores of glacial till at a range of moisture contents were subjected to freeze-thaw cycles over 24 hour periods. After drying, thin sections were analysed. Granic microfabrics had formed, and were best developed in clay loam soils with moisture content between field capacity and saturation. Possible formation processes are discussed.
Hydrogeology 892017 Modelling soil water dynamics in the unsaturated zone -state of the art Feddes, R A; Kabat, P; Van Bakel, P J T; Bronswijk, J J B; Halbertsma, J
J Hydrol VIO0. NI-3, July 1988. P69-111 The theory of water dynamics in the unsaturated zone is reviewed, considering mechanical and energy concepts, mass conservation, differential equation of unsaturated flow, Darcy's law, thermally induced soil water flow, swelling soils, frozen soils, and water extraction by roots. Modelling water dynamics in the unsaturated zone is discussed, introducing
892019 Intermittent measurement of flow rates, flow directions and permeabilities in a saturated medium using radioactive tracers (In French) Longere, P; Terriere, J; Tinette, R; Vecoven, J Bull Liaison Labs Ponts Chaassees N155, May-June 1988,
P73-80 Study of movement of groundwater is an important part of site investigation. A procedure is described which uses radioactive tracers (ln113 and Br82) to follow flow of subsurface water. It can be used to determine flow rates and direction of flow using a single piezometer. The test and its interpretation and instrumentation are described, and its application in alluvial formations in France is illustrated. The many uses for this test and its limitations arc discussed. 892020 Groundwater flow and transport modeling Konikow, L F; Mercer, J W
J Hydrol VIO0, NI-3, July 1988, P379-409 A review of the theoretical basis and practical use of groundwater flow and solute transport models is presented. Since there are errors and uncertainty in defining model parameters, models must be calibrated to obtain a best estimate of the parameters. For flow modelling, data are generally sufficient to allow calibration. For solute-transport modelling,lack of data not only limits calibration, but also causes uncertainty in process description. Where data are available, model reliability should be assessed on the basis of sensitivity tests and measures of goodness-of-fit. Some of these concepts are demonstrated by using two case histories. 101 refs. 892021 Water flow in unsaturated soil in layered slopes Miyazaki, T
J Hydrol VI02, NI-4, 30 Sept 1988, P201-214 Layered model slopes were prepared in transparent acrylic boxes, using sandy loam and gravel and dried plant material. The progress of the wetting front during vertical infiltration was traced and photographed. Wetting front advance was seen to halt at the inclined interface, but lateral flow along the interface continued. In horizontal layers, drainage is hindered, but lateral flow along the interface continues. These phenomena are explained by the saturated and unsaturated refraction of flow at the inclined interface.
C 1989 Pergamon Press pie. Reproduction not permitted RMM~:~:
D
Tectonophysies V152. NI/2. 10 Sept 1988, P119-135 Two magnetoteiluric stations were installed in Greece to monitor short period measurements. Estimation of the impedance tensor elements described the local magnetotelluric induction accurately. The residual electric field was determined and used in an attempt to detect precursory seismic electric signals (SES). Results show the method to be successful in resolving ambiguities about the nature of the reported SES. Analysis of the data showed that in 2 cases sources could not be related to earthquake processes, whilst in the other 3, the source of the suspected SES, although electric, could not be established with certainty. For earthquakes of small magnitude or large epicentral distance, detection of SES is extremely difficult.
solution of the governing equations by analytical, numerical, finite difference, finite element and boundary element approaches. Collection of data for model input and verification is discussed, including soil physical properties, spatial variation and scaling, soil water content and evapotranspiration. Simulation model extension to preferential flow and hysteresis is introduced, and 4 examples presented. 146 rcfs. 892018 Contaminant hydrogeology - dollars and sense Schwartz, F W
J Hydrol VIO0. NI-3, July 1988, P453-470 There has been a growth in interest in hydrogeology due to problems of groundwater contamination and waste (especially nuclear) disposal. Important developments, including direct and indirect methods for plume definition, measurements in deep boreholes, theoretical analysis and fractured rock hydrology, are discussed. Trends for the future are considered.
Frost action, permafrost and frozen ground Groundwater See a~o: 892099. 892135 892015 Two case histories of major frost heaving in refrigerated buildings: thermal analyses, repairs, and prevention Chapuis, R P Can Geotech J V25, N3. Aug 1988, P535-540 Frost action in soils is a complex phenomenon resulting from freezing of pore water and formation and growth of ice lenses. Two case studies in which frost penetration into soils underlying concrete slabs caused vertical expansion are presented. Thermal analysis was performed using a frost penetration equation for a muhilayered system with latent heat. Theoretical progression of the frost line and repair solutions are considered. 892016 Freeze-thaw effects on granular structure reorganization for soil materials of varying texture and moisture content Pawluk, S Can J Soil Sci V68. N3, Aug 1988. P485-494 Experiments were undertaken to determine whether microfabrics could be produced in soils using freeze-thaw. Undisturbed cores of glacial till at a range of moisture contents were subjected to freeze-thaw cycles over 24 hour periods. After drying, thin sections were analysed. Granic microfabrics had formed, and were best developed in clay loam soils with moisture content between field capacity and saturation. Possible formation processes are discussed.
Hydrogeology 892017 Modelling soil water dynamics in the unsaturated zone -state of the art Feddes, R A; Kabat, P; Van Bakel, P J T; Bronswijk, J J B; Halbertsma, J
J Hydrol VIO0. NI-3, July 1988. P69-111 The theory of water dynamics in the unsaturated zone is reviewed, considering mechanical and energy concepts, mass conservation, differential equation of unsaturated flow, Darcy's law, thermally induced soil water flow, swelling soils, frozen soils, and water extraction by roots. Modelling water dynamics in the unsaturated zone is discussed, introducing
892019 Intermittent measurement of flow rates, flow directions and permeabilities in a saturated medium using radioactive tracers (In French) Longere, P; Terriere, J; Tinette, R; Vecoven, J Bull Liaison Labs Ponts Chaassees N155, May-June 1988,
P73-80 Study of movement of groundwater is an important part of site investigation. A procedure is described which uses radioactive tracers (ln113 and Br82) to follow flow of subsurface water. It can be used to determine flow rates and direction of flow using a single piezometer. The test and its interpretation and instrumentation are described, and its application in alluvial formations in France is illustrated. The many uses for this test and its limitations arc discussed. 892020 Groundwater flow and transport modeling Konikow, L F; Mercer, J W
J Hydrol VIO0, NI-3, July 1988, P379-409 A review of the theoretical basis and practical use of groundwater flow and solute transport models is presented. Since there are errors and uncertainty in defining model parameters, models must be calibrated to obtain a best estimate of the parameters. For flow modelling, data are generally sufficient to allow calibration. For solute-transport modelling,lack of data not only limits calibration, but also causes uncertainty in process description. Where data are available, model reliability should be assessed on the basis of sensitivity tests and measures of goodness-of-fit. Some of these concepts are demonstrated by using two case histories. 101 refs. 892021 Water flow in unsaturated soil in layered slopes Miyazaki, T
J Hydrol VI02, NI-4, 30 Sept 1988, P201-214 Layered model slopes were prepared in transparent acrylic boxes, using sandy loam and gravel and dried plant material. The progress of the wetting front during vertical infiltration was traced and photographed. Wetting front advance was seen to halt at the inclined interface, but lateral flow along the interface continued. In horizontal layers, drainage is hindered, but lateral flow along the interface continues. These phenomena are explained by the saturated and unsaturated refraction of flow at the inclined interface.
C 1989 Pergamon Press pie. Reproduction not permitted RMM~:~:
D