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• 21. [Image] Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976

  	Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976 Author: Costain, J.K. Year: 1976 Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and geophysical data. An optimum site for geothermal development in the tectonically stable eastern United States will probably be associated with crustal igneous rocks containing relatively high concentrations of radiogenic heat-producing elements buried beneath an insulating blanket of sediments of low thermal conductivity. Evaluation of plutonic rocks exposed in the Piedmont will aid in the interpretation of gravity and magnetic data for the Atlantic Coastal Plain. Initial results of determination of heat generation from surface samples in South Caroline are encouraging, especially if granitic igneous rocks of similar heat generation can be found beneath sedimentary insulation. Continues logging of existing wells in Coastal Plain sediments supports earlier conclusion that these sediments do behave as efficient sedimentary insulators. Higher temperatures appear to be reached at shallower depths for wells drilled in Coastal Plain sediments in the vicinity of the Georgetown, South Carolina gravity law. Detailed structural mapping in the vicinity of the warm springs in northwestern Virginia has confirmed structural control of the warm springs, and has revealed the existence of kink bands. The kink bands could be related to the development of zones of vertical permeability which serve as conduits in sedimentary rocks for ascending hot water. Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976 Author: Costain, J.K. Year: 1976 Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and geophysical data. An optimum site for geothermal development in the tectonically stable eastern United States will probably be associated with crustal igneous rocks containing relatively high concentrations of radiogenic heat-producing elements buried beneath an insulating blanket of sediments of low thermal conductivity. Evaluation of plutonic rocks exposed in the Piedmont will aid in the interpretation of gravity and magnetic data for the Atlantic Coastal Plain. Initial results of determination of heat generation from surface samples in South Caroline are encouraging, especially if granitic igneous rocks of similar heat generation can be found beneath sedimentary insulation. Continues logging of existing wells in Coastal Plain sediments supports earlier conclusion that these sediments do behave as efficient sedimentary insulators. Higher temperatures appear to be reached at shallower depths for wells drilled in Coastal Plain sediments in the vicinity of the Georgetown, South Carolina gravity law. Detailed structural mapping in the vicinity of the warm springs in northwestern Virginia has confirmed structural control of the warm springs, and has revealed the existence of kink bands. The kink bands could be related to the development of zones of vertical permeability which serve as conduits in sedimentary rocks for ascending hot water. Close

• 22. [Image] Subsurface investigations at the Roosevelt KGRA, Utah. Final report

  	An investigation of the geothermal reservoir in the Roosevelt Hot Springs Known Geothermal Resource Area in Utah was carried out. The objective of this effort was to develop predictions for well production ...
  	Citation × Citation Citation Abstract Copy Title: Subsurface investigations at the Roosevelt KGRA, Utah. Final report Author: Butz, J. Year: 1979 An investigation of the geothermal reservoir in the Roosevelt Hot Springs Known Geothermal Resource Area in Utah was carried out. The objective of this effort was to develop predictions for well production capacities, based on data taken during field tests and through use of a computer model. In turn, the production information could then be used in design optimization and economic analyses for development of the resource under study. Flow tests of a geothermal well, Utah State 14-2, were conducted. Data consisting of pressure and temperature logs as a function of depth were obtained. Maximum recorded temperature was 503/sup 0/F (262/sup 0/C) and maximum pressure, 954 psia (6.58MPa) as measured under flow conditions. Tests were run at rates up to 580,000 lb/hr (73.3 kg/sec) total flow. The information gathered during the testing was reduced and compared to results of a predictive computer model. Reservoir conditions in the Roosevelt Hot Springs KGRA are such that two-phase flow exists in the wellbore and, in some cases, also in the reservoir itself. The computer model employed in the analysis reflects current efforts to improve the state-of-the-art in the prediction of two-phase pressure drops in vertical systems. Predictions at flowrates of up to 300,000 lb/hr (38 kg/sec) matched quite well with test data, while modeling at higher flowrates (to maximum tested) showed progressively greater deviation from test data. Cause of the observed degradation is postulated to be the movement of the flash horizon into the reservoir, due to drawdown at high flowrates; DOE/ET/28389-1 Title: Subsurface investigations at the Roosevelt KGRA, Utah. Final report Author: Butz, J. Year: 1979 An investigation of the geothermal reservoir in the Roosevelt Hot Springs Known Geothermal Resource Area in Utah was carried out. The objective of this effort was to develop predictions for well production capacities, based on data taken during field tests and through use of a computer model. In turn, the production information could then be used in design optimization and economic analyses for development of the resource under study. Flow tests of a geothermal well, Utah State 14-2, were conducted. Data consisting of pressure and temperature logs as a function of depth were obtained. Maximum recorded temperature was 503/sup 0/F (262/sup 0/C) and maximum pressure, 954 psia (6.58MPa) as measured under flow conditions. Tests were run at rates up to 580,000 lb/hr (73.3 kg/sec) total flow. The information gathered during the testing was reduced and compared to results of a predictive computer model. Reservoir conditions in the Roosevelt Hot Springs KGRA are such that two-phase flow exists in the wellbore and, in some cases, also in the reservoir itself. The computer model employed in the analysis reflects current efforts to improve the state-of-the-art in the prediction of two-phase pressure drops in vertical systems. Predictions at flowrates of up to 300,000 lb/hr (38 kg/sec) matched quite well with test data, while modeling at higher flowrates (to maximum tested) showed progressively greater deviation from test data. Cause of the observed degradation is postulated to be the movement of the flash horizon into the reservoir, due to drawdown at high flowrates; DOE/ET/28389-1 Close

• 23. [Image] Downhole Electrical Detection of Hydraulic Fractures in GT-2 and EE-1

  	Electrical geophysical methods including mise a la masse and self-potential (SP) for determination of hydraulic fracture characteristics were used at the hot dry rock geothermal project. Electrical and ...
  	Citation × Citation Citation Abstract Copy Title: Downhole Electrical Detection of Hydraulic Fractures in GT-2 and EE-1 Author: Kintzinger, P.R. Year: 1977 Electrical geophysical methods including mise a la masse and self-potential (SP) for determination of hydraulic fracture characteristics were used at the hot dry rock geothermal project. Electrical and induction logs indicated that the resistivity contrast between the granite and 200/sup 0/C water at the 2926-m (9600-ft) depth is a factor of 1000 or more. Thus the water in a hydraulic fracture, formed to connect two adjacent deep holes, is a good conductor compared to the confining granite. Mise a la masse-type measurements were made to help determine the characteristics for hydraulic fractures formed in each of the two geothermal holes GT-2 and EE-1. Once a hydraulic fracture has been formed, mise a la masse effects are obtained both with the fracture pressurized above hydrostatic and when depressurized to hydrostatic. This indicates that once the fracture has been created, enough natural propping exists that a conductive zone persists even when the fracture is deflated. A fracture was formed in a 18-m (60-ft) zone immediately below 1957 m (6420 ft) in EE-1. Later a set of SP logs was run in this zone with no pressure, with pressure building, with pressure decreasing, and again with the fracture depressurized. Results show that during times of change of parameters in hydraulically fractured regions in the hole, natural SP logging helps to determine the position of the fracture. However, after a fracture has come to equilibrium with fluid parameters such as temperature, pressure, salinity, and pH, an effect of the fracture may not be evident. Self-potential logs provide an excellent method for locating the bottom of steel casing that has been set in the hole Title: Downhole Electrical Detection of Hydraulic Fractures in GT-2 and EE-1 Author: Kintzinger, P.R. Year: 1977 Electrical geophysical methods including mise a la masse and self-potential (SP) for determination of hydraulic fracture characteristics were used at the hot dry rock geothermal project. Electrical and induction logs indicated that the resistivity contrast between the granite and 200/sup 0/C water at the 2926-m (9600-ft) depth is a factor of 1000 or more. Thus the water in a hydraulic fracture, formed to connect two adjacent deep holes, is a good conductor compared to the confining granite. Mise a la masse-type measurements were made to help determine the characteristics for hydraulic fractures formed in each of the two geothermal holes GT-2 and EE-1. Once a hydraulic fracture has been formed, mise a la masse effects are obtained both with the fracture pressurized above hydrostatic and when depressurized to hydrostatic. This indicates that once the fracture has been created, enough natural propping exists that a conductive zone persists even when the fracture is deflated. A fracture was formed in a 18-m (60-ft) zone immediately below 1957 m (6420 ft) in EE-1. Later a set of SP logs was run in this zone with no pressure, with pressure building, with pressure decreasing, and again with the fracture depressurized. Results show that during times of change of parameters in hydraulically fractured regions in the hole, natural SP logging helps to determine the position of the fracture. However, after a fracture has come to equilibrium with fluid parameters such as temperature, pressure, salinity, and pH, an effect of the fracture may not be evident. Self-potential logs provide an excellent method for locating the bottom of steel casing that has been set in the hole Close

• 24. [Image] Preliminary Petrographic and Geophysical Interpretations of the Exploratory Geothermal Drill Hole and Core, Redstone, New Hampshire

  	A 3000 foot diamond drill hole was drilled in the Conway Granite in Redstone, New Hampshire. A comprehensive detailed petrographic and physical study of this core was made. The purpose of this study is ...
  	Citation × Citation Citation Abstract Copy Title: Preliminary Petrographic and Geophysical Interpretations of the Exploratory Geothermal Drill Hole and Core, Redstone, New Hampshire Author: Hoag, R.B. Jr. Year: 1977 A 3000 foot diamond drill hole was drilled in the Conway Granite in Redstone, New Hampshire. A comprehensive detailed petrographic and physical study of this core was made. The purpose of this study is to supply a sound data base for future geothermal and uranium-thorium studies of the drill core. An estimate of the heat flow potential of the Redstone drill hole gives a heat flow of 1.9 HFU. If only the red phase of the Conway Granite had been intersected the heat flow may have been as much as 2.7 HFU, reaching a temperature of 260/sup 0/C at 6 km. The drill hole intersected four lithologies; the green and red phase of the Conway Granite, the Albany quartz syenite and a medium-grained, hastingsite-biotite granite. The red phase has the highest and most irregular radioactivity. The irregularity is mainly due to minor variations in lithology. The Drill core intersected several alteration zones up to a thickness of 150 feet. These alteration zones represent passage of low to medium temperature fluids which might have been mineralized. The Conway Granite has the physical and chemical characteristics necessary for the formation of vein type uranium deposits. The presence of unexplained radiometric anomalies lends support to the existence of such deposits Title: Preliminary Petrographic and Geophysical Interpretations of the Exploratory Geothermal Drill Hole and Core, Redstone, New Hampshire Author: Hoag, R.B. Jr. Year: 1977 A 3000 foot diamond drill hole was drilled in the Conway Granite in Redstone, New Hampshire. A comprehensive detailed petrographic and physical study of this core was made. The purpose of this study is to supply a sound data base for future geothermal and uranium-thorium studies of the drill core. An estimate of the heat flow potential of the Redstone drill hole gives a heat flow of 1.9 HFU. If only the red phase of the Conway Granite had been intersected the heat flow may have been as much as 2.7 HFU, reaching a temperature of 260/sup 0/C at 6 km. The drill hole intersected four lithologies; the green and red phase of the Conway Granite, the Albany quartz syenite and a medium-grained, hastingsite-biotite granite. The red phase has the highest and most irregular radioactivity. The irregularity is mainly due to minor variations in lithology. The Drill core intersected several alteration zones up to a thickness of 150 feet. These alteration zones represent passage of low to medium temperature fluids which might have been mineralized. The Conway Granite has the physical and chemical characteristics necessary for the formation of vein type uranium deposits. The presence of unexplained radiometric anomalies lends support to the existence of such deposits Close

• 25. [Image] Geothermal Resources, Vicksburg Formation, Texas Gulf Coast

  	The potential for discovering geopressured geothermal reservoirs in the Vicksburg Formation is limited to Hidalgo County along the Lower Texas Gulf Coast. In Hidalgo County, an area of approximately 385 ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Resources, Vicksburg Formation, Texas Gulf Coast Author: Loucks, R.G. Year: 1978 The potential for discovering geopressured geothermal reservoirs in the Vicksburg Formation is limited to Hidalgo County along the Lower Texas Gulf Coast. In Hidalgo County, an area of approximately 385 square miles (designated the Vicksburg Fairway) contains up to 1,300 feet of geopressured sandstones with fluid temperatures greater than 300/sup 0/F. In-place effective permeability, however, averages less than 1 millidarcy in the Vicksburg sandstones because of fine grain size and extensive late carbonate cementation. Also, areal extent of individual reservoirs is limited in a dip direction by growth faults and in a strike direction by the lenticular morphology of the sandstone bodies. In conclusion, under the present specifications set for a geothermal fairway, the Vicksburg has minimal potential because of low reservoir deliverability, which is constrained by low permeability and somewhat limited reservoir continuity. If future tests indicate that lower permeabilities are acceptable, the Vicksburg Fairway should be reconsidered because of the presence of extremely thick sandstone bodies Title: Geothermal Resources, Vicksburg Formation, Texas Gulf Coast Author: Loucks, R.G. Year: 1978 The potential for discovering geopressured geothermal reservoirs in the Vicksburg Formation is limited to Hidalgo County along the Lower Texas Gulf Coast. In Hidalgo County, an area of approximately 385 square miles (designated the Vicksburg Fairway) contains up to 1,300 feet of geopressured sandstones with fluid temperatures greater than 300/sup 0/F. In-place effective permeability, however, averages less than 1 millidarcy in the Vicksburg sandstones because of fine grain size and extensive late carbonate cementation. Also, areal extent of individual reservoirs is limited in a dip direction by growth faults and in a strike direction by the lenticular morphology of the sandstone bodies. In conclusion, under the present specifications set for a geothermal fairway, the Vicksburg has minimal potential because of low reservoir deliverability, which is constrained by low permeability and somewhat limited reservoir continuity. If future tests indicate that lower permeabilities are acceptable, the Vicksburg Fairway should be reconsidered because of the presence of extremely thick sandstone bodies Close

• 26. [Image] Utilization of geothermal energy in the mining and processing of tungsten ore: Final report

  	The engineering, economic, and environmental feasibility of the use of low and moderate temperature geothermal heat in the mining and processing of tungsten ore is explored. The following are covered: ...
  	Citation × Citation Citation Abstract Copy Title: Utilization of geothermal energy in the mining and processing of tungsten ore: Final report Author: Erickson, M.V. Year: 1981 The engineering, economic, and environmental feasibility of the use of low and moderate temperature geothermal heat in the mining and processing of tungsten ore is explored. The following are covered: general engineering evaluation, design of a geothermal energy system, economics, the geothermal resource, the institutional barriers assessment, environmental factors, an alternate geothermal energy source, and alternates to geothermal development. (MHR); DOE/ET/27232-T5 Title: Utilization of geothermal energy in the mining and processing of tungsten ore: Final report Author: Erickson, M.V. Year: 1981 The engineering, economic, and environmental feasibility of the use of low and moderate temperature geothermal heat in the mining and processing of tungsten ore is explored. The following are covered: general engineering evaluation, design of a geothermal energy system, economics, the geothermal resource, the institutional barriers assessment, environmental factors, an alternate geothermal energy source, and alternates to geothermal development. (MHR); DOE/ET/27232-T5 Close

• 27. [Image] Industrial application of geothermal energy in Southeast Idaho

  	Those phosphate related and food processing industries in Southeastern Idaho are identified which require large energy inputs and the potential for direct application of geothermal energy is assessed. ...
  	Citation × Citation Citation Abstract Copy Title: Industrial application of geothermal energy in Southeast Idaho Author: Batdorf, J.A. Year: 1980 Those phosphate related and food processing industries in Southeastern Idaho are identified which require large energy inputs and the potential for direct application of geothermal energy is assessed. The total energy demand is given along with that fractional demand that can be satisfied by a geothermal source of known temperature. The potential for geothermal resource development is analyzed by examining the location of known thermal springs and wells, the location of state and federal geothermal exploration leases, and the location of federal and state oil and gas leasing activity in Southeast Idaho. Information is also presented regarding the location of geothermal, oil, and gas exploration wells in Southeast Idaho. The location of state and federal phosphate mining leases is also presented. This information is presented in table and map formats to show the proximity of exploration and development activities to current food and phosphate processing facilities and phosphate mining activities. (MHR); DOE/ID/12010-4 Title: Industrial application of geothermal energy in Southeast Idaho Author: Batdorf, J.A. Year: 1980 Those phosphate related and food processing industries in Southeastern Idaho are identified which require large energy inputs and the potential for direct application of geothermal energy is assessed. The total energy demand is given along with that fractional demand that can be satisfied by a geothermal source of known temperature. The potential for geothermal resource development is analyzed by examining the location of known thermal springs and wells, the location of state and federal geothermal exploration leases, and the location of federal and state oil and gas leasing activity in Southeast Idaho. Information is also presented regarding the location of geothermal, oil, and gas exploration wells in Southeast Idaho. The location of state and federal phosphate mining leases is also presented. This information is presented in table and map formats to show the proximity of exploration and development activities to current food and phosphate processing facilities and phosphate mining activities. (MHR); DOE/ID/12010-4 Close

• 28. [Image] Hawaii Geothermal Resource Assessment Program: western state cooperative direct heat resource assessment, Phase I. Final report

  	A regional geothermal resource assessment has been conducted for the major islands in the Hawaiian chain. The assessment was made through the compilation and evaluation of the readily accessible geological, ...
  	Citation × Citation Citation Abstract Copy Title: Hawaii Geothermal Resource Assessment Program: western state cooperative direct heat resource assessment, Phase I. Final report Year: 1978 A regional geothermal resource assessment has been conducted for the major islands in the Hawaiian chain. The assessment was made through the compilation and evaluation of the readily accessible geological, geochemical, and geophysical data for the Hawaiian archipelago which has been acquired during the last two decades. The geologic criteria used in the identification of possible geothermal reservoirs were: age and location of most recent volcanism on the island and the geologic structure of each island. The geochemical anomalies used as traces for geothermally altered ground water were: elevated silica concentrations and elevated chloride/magnesium ion ratios. Geophysical data used to identify subsurface structure which may have geothermal potential were: aeromagnetic anomalies, gravity anomalies, and higher than normal well and basal spring discharge temperatures. Geophysical and geochemical anomalies which may be the result of subsurface thermal effects have been identified on the islands of Hawaii, Maui, Molokai and Oahu; DOE/ID/01713-4 Title: Hawaii Geothermal Resource Assessment Program: western state cooperative direct heat resource assessment, Phase I. Final report Year: 1978 A regional geothermal resource assessment has been conducted for the major islands in the Hawaiian chain. The assessment was made through the compilation and evaluation of the readily accessible geological, geochemical, and geophysical data for the Hawaiian archipelago which has been acquired during the last two decades. The geologic criteria used in the identification of possible geothermal reservoirs were: age and location of most recent volcanism on the island and the geologic structure of each island. The geochemical anomalies used as traces for geothermally altered ground water were: elevated silica concentrations and elevated chloride/magnesium ion ratios. Geophysical data used to identify subsurface structure which may have geothermal potential were: aeromagnetic anomalies, gravity anomalies, and higher than normal well and basal spring discharge temperatures. Geophysical and geochemical anomalies which may be the result of subsurface thermal effects have been identified on the islands of Hawaii, Maui, Molokai and Oahu; DOE/ID/01713-4 Close

• 29. [Image] Washington: A Guide to Geothermal Energy Development

  	A brief overview is given of the geological characteristics of each region of the state as they relate to potential geothermal development. Those exploration methods which can lead to the siting of a deep ...
  	Citation × Citation Citation Abstract Copy Title: Washington: A Guide to Geothermal Energy Development Author: Bloomquist, R.G. Year: 1980 A brief overview is given of the geological characteristics of each region of the state as they relate to potential geothermal development. Those exploration methods which can lead to the siting of a deep exploration well are described. Requirements and techniques needed for drilling deeper higher temperature exploration and production wells are presented. Electrical generation, direct utilization, and indirect utilization are reviewed. Economic factors of direct use projects are presented. A general guide to the regulatory framework affecting geothermal energy development is provided. The general steps necessary to gain access to explore, develop, distribute, and use geothermal resources are outlined (MHR) Title: Washington: A Guide to Geothermal Energy Development Author: Bloomquist, R.G. Year: 1980 A brief overview is given of the geological characteristics of each region of the state as they relate to potential geothermal development. Those exploration methods which can lead to the siting of a deep exploration well are described. Requirements and techniques needed for drilling deeper higher temperature exploration and production wells are presented. Electrical generation, direct utilization, and indirect utilization are reviewed. Economic factors of direct use projects are presented. A general guide to the regulatory framework affecting geothermal energy development is provided. The general steps necessary to gain access to explore, develop, distribute, and use geothermal resources are outlined (MHR) Close

• 30. [Image] Exploration Methods for Hot Dry Rock. Report of the Panel Held June 22, 1976

  	The geological and geophysical characteristics of hot dry rock (HDR) necessary for an effective exploration program were discussed. The type of HDR project discussed, that being developed by the Los Alamos ...
  	Citation × Citation Citation Abstract Copy Title: Exploration Methods for Hot Dry Rock. Report of the Panel Held June 22, 1976 Author: West, F.G. (comp.) Year: 1977 The geological and geophysical characteristics of hot dry rock (HDR) necessary for an effective exploration program were discussed. The type of HDR project discussed, that being developed by the Los Alamos Scientific Laboratory (LASL), would utilize hydraulic fracturing to develop a large surface area in rock of low permeability, 10/sup -6/ darcys, and at temperatures greater than 200/sup 0/C. A better definition of the thermal regime in the crust and mantle at reconnaissance (hundreds to tens of kilometers) and exploration (tens of kilometers to 1 km) scales is needed. Geophysical methods capable of deep investigation would be used with the near-surface geologic information to extrapolate conditions at the depth of interest. Detection of HDR per se may be difficult because the contrast in physical properties of HDR and other rock is not always unambiguous, but boundaries between rock environments can be delineated. When patterns and coincidence of various types of geophysical anomalies and geologic maps are used, the probability of the detection of HDR is greatly increased, especially when a consistent picture is described. Various geophysical methods are required to detect these anomalies: (a) electromagnetic techniques can map deep electrically conductive structures, which to some extent can be used to infer isotherms. (b) Bouguer gravity maps corrected for regional topography are found to correlate with large silicic intrusive bodies, which are often associated with high heat flow. (c) isotherms and open crack systems at depth can be inferred from seismic wave attenuations, dispersions, and delay times. (d) heat flow measurements are useful as a primary tool and as a check on the results of other methods. Abstracts for individual presentations by the twelve panel members are included. 111 references Title: Exploration Methods for Hot Dry Rock. Report of the Panel Held June 22, 1976 Author: West, F.G. (comp.) Year: 1977 The geological and geophysical characteristics of hot dry rock (HDR) necessary for an effective exploration program were discussed. The type of HDR project discussed, that being developed by the Los Alamos Scientific Laboratory (LASL), would utilize hydraulic fracturing to develop a large surface area in rock of low permeability, 10/sup -6/ darcys, and at temperatures greater than 200/sup 0/C. A better definition of the thermal regime in the crust and mantle at reconnaissance (hundreds to tens of kilometers) and exploration (tens of kilometers to 1 km) scales is needed. Geophysical methods capable of deep investigation would be used with the near-surface geologic information to extrapolate conditions at the depth of interest. Detection of HDR per se may be difficult because the contrast in physical properties of HDR and other rock is not always unambiguous, but boundaries between rock environments can be delineated. When patterns and coincidence of various types of geophysical anomalies and geologic maps are used, the probability of the detection of HDR is greatly increased, especially when a consistent picture is described. Various geophysical methods are required to detect these anomalies: (a) electromagnetic techniques can map deep electrically conductive structures, which to some extent can be used to infer isotherms. (b) Bouguer gravity maps corrected for regional topography are found to correlate with large silicic intrusive bodies, which are often associated with high heat flow. (c) isotherms and open crack systems at depth can be inferred from seismic wave attenuations, dispersions, and delay times. (d) heat flow measurements are useful as a primary tool and as a check on the results of other methods. Abstracts for individual presentations by the twelve panel members are included. 111 references Close