- Email: [email protected]
Rapid geomorphological reconnaissance survey for road alignment in west Nepal
194A
SITE INVESTIGATIONS:REMOTE SENSING
isolation, and so the determination of the regional stress field is viewed as an inverse problem, the solution of which is the best fit of all relevant observations. This new approach is the integrated stress determination method and is detailed in full. -after Author 944172 Measuring in situ rock stress by borehole slotting H. F. Bock, in: Comprehensive rock engineering. Vol. 3, ed J.A. Hudson, (Pergamon), 1993, pp 433-443. Borehole slotting is a relatively new, self-contained technique which allows numerous, closely spaced and relatively cheap stress measurements to be carried out in boreholes without the necessity for ovemorin~. Borehole slotting has been tested in situ in parallel with conventional stress measuring techniques such as overcoring and hydraulic fracturing. Whilst providing results on the in situ stress state with at least comparable accuracy, it was found to have major advantages over the conventional methods with regard to speed of operation, reliability and economy. With both testing services and equipment now being commercially available, it can be expected that borehole slotting will be of increasing importance in the future. -from Author 944173 How do some field tests really work? The case of the NX-borehole j a c k F . E . Heuze, in: Comprehensive rock engineering. 1Ioi. 3, ed J.A. Hudson, (Pergamon), 1993, pp 683-692. Presents a historical perspective of the past trials and tribulations in the development of borehole jack techniques. Then, the positive building blocks axe summarized, and, finally, a procedure is described to analyze borehole jack data. Additional information regarding the practical use of the jack in the field is provided in a document available through the Lawrence Lxvermore National Laboratory. -from Author 944174 Rafurasos technikaval vegzett kozetfeszultseg. meresek M a g y a r o r s z a g o n (In situ stress measurements in H u n g a r y using the overcoring technique) P. Gemer, R. Porjesz & P. Szafian, Magyar Geofizika, 34(3), 1994, pp 134-142. The theoretical background of the overcoring technique, the description of the test sites, the processing of the data and the results of the measurements are discussed. In the overeoring technique the strain relaxation of a 10-20 cm long core sample removed from the in sire stress field is measured with a strain gauge cell. If the elastic properties of the rock are known, the magnimdas and the directions of the in situ stresses can be determined. The results show that the overcoring technique is very sensitive to the properties of the rock, the morphology and the geological structure of the site. However, consxdering these observations, valuable conclusions can be drawn concerning the recent stress field of the Earth's crust and the direction of the two horizontal principal stresses. -from English summary 944175 Measuring rock stress: case examples of rock engineering in J a p a n K. Sugawara & Y. Obara, in: Comprehensive rock engineering. Vol. 3, ed J.A. Hudson, (Pergamon), 1993, pp 533-552. The hemispherical-ended borehole technicjue, now in common use in Japan is described in detail. It is shown how the complete state of stress in a rock mass can be determined from the strains on the hemispherical bottom surface of a single borehole. The observation equation to be used in ractice, spherical diamond bits to convert the bottom of e borehole into a hemispherical shape, and a spherical strain cell to bond the necessary 16 strain gauges directly to the rock surface are introduced, as well as subsequent monitoring of the chan~es in strain through the overcoring operation by the continuous measurement system. Four case examples of the technique are given, and finally, compiling the results of the initial rock stress measurements,
the near-surface stress field in the Japanese islands is discussed. -from Authors
SITE INVESTIGATION AND FIELD OBSERVATION 944176 U n d e r g r o u n d disposal of radioactive waste C . S . Mogg & B. J. Breen, Mining Engineer, 153(391), 1994, pp 277-283. United Kingdom Nirex Limited (Nixex) is responsible for developing and managing a facility for the safe deep disposal of intermediate (ILW) and some low-level (LLW) radioactive waste. The company is concentrating its efforts on a ~proposed site at Sellalield in Cumbria. Borehole invesugauons are supplemented by seismic surveys, other geophysical sensing and geological mapping, Nirex announced plans in October 1992 to advance geological investigations by means of an underground Rock Characterisation Facility. The facility would give access to depth to around 800 m below Ordnance Datum in the strong, low permeabilit~ basement rocks of the Borrowdale Volcanic Group. Thin paper outlines the approach to repository design development work and outlines the Nirex future programme. -from Authors
Remote sensing and photographic techniques 944177 Modern surveying techniques for mining and civil engineering A. Chrzanowski, in: Comprehensive rock engineering. Vol. 3, ed LA. Hudson, (Pergamon), 1993, pp 773-809. This brief review of modem surve]ling techniques has shown that with the recent technologlcal developments in both geodetic and geotechnical instrumentation one may, at a cost, achieve almost any needed resolution and precision, full automation and practically real-time data processing. The development of space techniques such as GPS has revolutionized the traditional m e t l i ~ used to establish geodetic control networks and has opened new fields of geodetic surveying applications. Some sophisticated methods, particularly for deformation analysis, have been developed within the last few years. They requite, however, a sound undentanding of all the processes involved in the design, execution and postamdysis of the measurements. -from Author 944178 Strain accumulation 1986.1992 across the Reykjanes Peninsula plate boundary, Iceland, determined from GPS measurements E. Sturkell, F. Sigmundsson, P. Einarsson & R. Bilham, Geophysical Research Letters, 21(2), 1994, pp 125-128, Gc~S geodetic observations 1986-1992 spanning the lique plate boundary on the Reykjanes Peninsula, SW eland, show that left-lateral shear strain is accumulating in the area. The principal strain rates are: ¢1 = 0.255 ± 0.055 p ~ t r a J ~ r (extenston) at N121 + 6"E, and ¢~ = -0.I90 + 0.053 ~ t r a m / y r (contraction) at N31 +6"E, The principat axis ot extension is perpendicular to me strike of fractures within volcanic systems on the Peninsula. Continuous aseismic slip of the North American'Eurasian plates below a 5-11 km locking depth on the Peninsula can ex]~lain ~ e observed depth of earthquakes, the width o f the aetonnanon zone determined from recent fissuring and faulting, and the GPS-measurements of strain. -from Authors 944179 Rapid geomorpbological reconnaissance survey for road alignment in west Nepal G. J. Hearn, Bulletin - International Association of Engineering Geology, 48, 1993, pp 59-68. A rapid geomorphological reconnaissance survey of the 112 km Baltadi-Darchula road currently under construction in the Middle Himalaya of West Nepal is described, The first 30 km of the proposed road was under constmct~n when this 5 day survey commenced, to cover both the initial segment as well as an examination of the stability and practicability of the remainder of the 'alignment. A combi-
SITE INVESTIGATIONS:GEOPHYSICS
195A
nation of landslide and erosion mapping along the proposed alignment and interpretation of air photographs led to the recommendation to abandon the remainder of the alignment and adopted an alternative route, considered to be more stable. -from Author
and also by the lack of detailed studies on the key locations, such as the dam itself. The dam suffered changes and rotations of the axis and excavation problems in the pressure tunnel, undoubtedly caused by mbLnterpretation of the local geology before construction. -from Author
944180 Mapping the Xigaze (Tibet) ophiolite complex with Landsat Thematic Mapper data J . P . Matthews & A. S. G. Jones, Journal of Himalayan Geology, 3(1), 1992, pp 97-101. Decorrelation stretch and band ratio image enhancement techniques have been applied to a Landsat Thematic Mapper (TM) scene covermg the remote Xigaze Ophiolite. Vegetation or soil cover is sparse in this region, so maps generated from satellite imagery can compliment information gathered from field surveys. From Landsat data, a map has been drawn of the main ophiollte massif which gives a more accurate overview of the distribution of lithologies than do previously published maps. -from Authors
944185 Some aspects of seismic hazard assessment in national and local leveb in Albania S. Kociaj, in: Comprehensive approach to earthquake disaster mitigation, ed A. V o g e l & others, (Vieweg; Progress in Earthquake Research & Engineering, Vol. 4), 1993, pp 85-117. Albania is one of the most active seismic countries in the Mediterranean Region. The seismic hazard assessment was based on three main elements: earthquake loci on the basis of seismological and geological data; maximum seismic energy to be released by the expected earthquake loci; and surface effects of this energy expressed either through strong ground motion parameters or through seismic intensities. Hazard maps for the whole country are described, and case studies of hazard assessment on a local level are presented. -G.E.Hodgson
Structural and geotechnical mapping 944181 An expert system approach to liquefaction analysis, part 1: development and implementation M.A. Chouicha & T. J. Siller, Computers & Geotechnics, 16(1), 1994, pp 1-35. This paper presents the development of the rule-based expert system, LIQUEFY, which evaluates the liquefaction potential of sites using several commonly accepted liquefaction evaluation methods. In this paper the issues in the design of the rule-based are addressed including: knowledge acquisition, knowledge representation, and system validation. LIQUEFY was developed for the personal computer and includes 470 rules, an explanation facility, and methods for handling uncertainty in input data and resulting conclusions. -Authors 944182 An expert system approach to liquefaction analysis, part 2: evaluation M . A . Chouicha, T. J. Siller & W. A. Charlie, Computers & Geotechnics, 16(1), 1994, pp 37-69. This is the second paper in a two-part series describing the development of LIQUEFY. The functional issues in designing LIQUEFY are presented: the implementation of five different methods for liquefaction hazards assessment and their incorporation into a unique framework for liquefaction evaluation. The system ~roups the implemented liquefaction methods into a preliminary and a final task. The performance of LIQUEFY is compared to pubfished case histories. -from Authors 944183 Understanding subsalt overpressure may reduce drilling risks J. O'Brien & I. Lerche, Oil & Gas Journal, 92(4), 1994, pp 28-34. An analysis of the subsalt physical environment can help engineers and geologists understand the potential for overpressure, which may lead to drilling problems during exptoration near salt sheets. Trapped hydrocarbons in format ions underlying salt sheets have become a promising exploration play in the Gulf of Mexico. Although subsalt targets share many characteristics with nonsalt targets, the presence of the salt body can influence the physical prol>erties of the target in a number of ways. Some of these factors may be critical to the success of a well and need to be addressed in the prospect evaluation and during well planning. -from Authors 944184 The Agua del Toro Dam, Mendoza, Argentina - a case of insufficient surface geology studies affecting underground excavations A . J . Amos, in: Comprehensive rock engineering. 1Iol. 5, ed J.A. Hudson, (Pergamon), 1993, pp 133-146. The Agua del Toro dam, pressure tunnel and powerhouse illustrate the effect of insufficient geological studies on the overall construction and represent a case which could have failed to deliver a very important source of energy to the Interconnected System or" Argentina during the 1970s. The [eology of the Agua del Toro project is by no means simple, being complicated by a rather bizarre stratigraphy .
RMM$ 31:4-,]
,
,
Geophysical techniques 944186
The geoeleeWical methods
exploration
in geophysical
M. S. Zhdanov & G. V. Keller, (Elsevier;Methods in Geochemistry and Geophyies, 31),ISBN (hardback) 0 A ~ 89678 3, price Dfl 375.00 (US$214.25), 1994, 873 pp, index. The first four chapters provide an introduction to electrical techniques in geophysics, covering rock and mineral properties and EM field behaviour. Chapters 5-7 deal with the standard geoelectrical techniques o~ direct current (DC), maj~,neto~Huric ( ~ ) , and controlled source electro.magneuc tt~M) memoas, t:napters ~-tl provide oetails on aspects of geoeiectrical theory common to all techniques, and are: modelling and simulation; insensitivity and sxmulation; practical aspects of data aquisition; and interpretation. Chapter 12 provides details of other methodologies, such as airborne EM surveys, borehole techniques , ground penetrating radar (GPR), and piezoelectric method (PEP). Chapter 13 gives details of 13 case studies using geoelectrical techniques from around the world, whilst the final chapter provides some generalisations for geoelectrical work. Two appendices provide details on mathematical conventions and FORTRAN programming. -R.Gower 944187 Geophysical testing for rock engineering K. Sassa, in: Comprehensive rock engineering. VoT. 3, ed J.A. Hudson, (Pergamon), 1993, pp 635-650. In this chapter, seismic testing within a borehole and between boreholes, and seismic tomography axe explained. The 'downhole method' is the most effective method to measure elastic wave velocities and attenuations in the borehole direction. By use of the 'cross-hole method', average velocities in the rock mass between sources and receivers are measured. Therefore, average pro])erties of the rock mass are obtained by this method. Setsratc tomography is the only technique able to obtain the two-dimensional distribution of propagation velocities and attenuation characteristics of elastic waves. -from Author 944188 Seismic imaging using micr0,earthquakes induced by hydraulic fracturing L.V. Block, C. H. Cheng, M. C. Fehler & W. S. Phillips, Geophysics, 59(1), 1994, pp 102-112. Seismic imaging using microearthquakes induced by ydraulic fracturing produces a three-dimensional (3-D), S-wave velocity model of the fractured zone, improves the calculated locations of the microearthquakes, and may lead to be.tter estimates of fracture plane orientations, fracture density, and water flow paths. Such information is important for predicting me amount of heat energy that may be extracted from geothermal reservoir. A fractured zone was created at the Los Alamns Hot Dry Rock Reservoir in north-central New Mexico within otherwise impermeable basement rock by injecting 21 000 m 3 of water into a borehole under high pressure at a depth of 3.5 kin. Induced
SITE INVESTIGATIONS:REMOTE SENSING
isolation, and so the determination of the regional stress field is viewed as an inverse problem, the solution of which is the best fit of all relevant observations. This new approach is the integrated stress determination method and is detailed in full. -after Author 944172 Measuring in situ rock stress by borehole slotting H. F. Bock, in: Comprehensive rock engineering. Vol. 3, ed J.A. Hudson, (Pergamon), 1993, pp 433-443. Borehole slotting is a relatively new, self-contained technique which allows numerous, closely spaced and relatively cheap stress measurements to be carried out in boreholes without the necessity for ovemorin~. Borehole slotting has been tested in situ in parallel with conventional stress measuring techniques such as overcoring and hydraulic fracturing. Whilst providing results on the in situ stress state with at least comparable accuracy, it was found to have major advantages over the conventional methods with regard to speed of operation, reliability and economy. With both testing services and equipment now being commercially available, it can be expected that borehole slotting will be of increasing importance in the future. -from Author 944173 How do some field tests really work? The case of the NX-borehole j a c k F . E . Heuze, in: Comprehensive rock engineering. 1Ioi. 3, ed J.A. Hudson, (Pergamon), 1993, pp 683-692. Presents a historical perspective of the past trials and tribulations in the development of borehole jack techniques. Then, the positive building blocks axe summarized, and, finally, a procedure is described to analyze borehole jack data. Additional information regarding the practical use of the jack in the field is provided in a document available through the Lawrence Lxvermore National Laboratory. -from Author 944174 Rafurasos technikaval vegzett kozetfeszultseg. meresek M a g y a r o r s z a g o n (In situ stress measurements in H u n g a r y using the overcoring technique) P. Gemer, R. Porjesz & P. Szafian, Magyar Geofizika, 34(3), 1994, pp 134-142. The theoretical background of the overcoring technique, the description of the test sites, the processing of the data and the results of the measurements are discussed. In the overeoring technique the strain relaxation of a 10-20 cm long core sample removed from the in sire stress field is measured with a strain gauge cell. If the elastic properties of the rock are known, the magnimdas and the directions of the in situ stresses can be determined. The results show that the overcoring technique is very sensitive to the properties of the rock, the morphology and the geological structure of the site. However, consxdering these observations, valuable conclusions can be drawn concerning the recent stress field of the Earth's crust and the direction of the two horizontal principal stresses. -from English summary 944175 Measuring rock stress: case examples of rock engineering in J a p a n K. Sugawara & Y. Obara, in: Comprehensive rock engineering. Vol. 3, ed J.A. Hudson, (Pergamon), 1993, pp 533-552. The hemispherical-ended borehole technicjue, now in common use in Japan is described in detail. It is shown how the complete state of stress in a rock mass can be determined from the strains on the hemispherical bottom surface of a single borehole. The observation equation to be used in ractice, spherical diamond bits to convert the bottom of e borehole into a hemispherical shape, and a spherical strain cell to bond the necessary 16 strain gauges directly to the rock surface are introduced, as well as subsequent monitoring of the chan~es in strain through the overcoring operation by the continuous measurement system. Four case examples of the technique are given, and finally, compiling the results of the initial rock stress measurements,
the near-surface stress field in the Japanese islands is discussed. -from Authors
SITE INVESTIGATION AND FIELD OBSERVATION 944176 U n d e r g r o u n d disposal of radioactive waste C . S . Mogg & B. J. Breen, Mining Engineer, 153(391), 1994, pp 277-283. United Kingdom Nirex Limited (Nixex) is responsible for developing and managing a facility for the safe deep disposal of intermediate (ILW) and some low-level (LLW) radioactive waste. The company is concentrating its efforts on a ~proposed site at Sellalield in Cumbria. Borehole invesugauons are supplemented by seismic surveys, other geophysical sensing and geological mapping, Nirex announced plans in October 1992 to advance geological investigations by means of an underground Rock Characterisation Facility. The facility would give access to depth to around 800 m below Ordnance Datum in the strong, low permeabilit~ basement rocks of the Borrowdale Volcanic Group. Thin paper outlines the approach to repository design development work and outlines the Nirex future programme. -from Authors
Remote sensing and photographic techniques 944177 Modern surveying techniques for mining and civil engineering A. Chrzanowski, in: Comprehensive rock engineering. Vol. 3, ed LA. Hudson, (Pergamon), 1993, pp 773-809. This brief review of modem surve]ling techniques has shown that with the recent technologlcal developments in both geodetic and geotechnical instrumentation one may, at a cost, achieve almost any needed resolution and precision, full automation and practically real-time data processing. The development of space techniques such as GPS has revolutionized the traditional m e t l i ~ used to establish geodetic control networks and has opened new fields of geodetic surveying applications. Some sophisticated methods, particularly for deformation analysis, have been developed within the last few years. They requite, however, a sound undentanding of all the processes involved in the design, execution and postamdysis of the measurements. -from Author 944178 Strain accumulation 1986.1992 across the Reykjanes Peninsula plate boundary, Iceland, determined from GPS measurements E. Sturkell, F. Sigmundsson, P. Einarsson & R. Bilham, Geophysical Research Letters, 21(2), 1994, pp 125-128, Gc~S geodetic observations 1986-1992 spanning the lique plate boundary on the Reykjanes Peninsula, SW eland, show that left-lateral shear strain is accumulating in the area. The principal strain rates are: ¢1 = 0.255 ± 0.055 p ~ t r a J ~ r (extenston) at N121 + 6"E, and ¢~ = -0.I90 + 0.053 ~ t r a m / y r (contraction) at N31 +6"E, The principat axis ot extension is perpendicular to me strike of fractures within volcanic systems on the Peninsula. Continuous aseismic slip of the North American'Eurasian plates below a 5-11 km locking depth on the Peninsula can ex]~lain ~ e observed depth of earthquakes, the width o f the aetonnanon zone determined from recent fissuring and faulting, and the GPS-measurements of strain. -from Authors 944179 Rapid geomorpbological reconnaissance survey for road alignment in west Nepal G. J. Hearn, Bulletin - International Association of Engineering Geology, 48, 1993, pp 59-68. A rapid geomorphological reconnaissance survey of the 112 km Baltadi-Darchula road currently under construction in the Middle Himalaya of West Nepal is described, The first 30 km of the proposed road was under constmct~n when this 5 day survey commenced, to cover both the initial segment as well as an examination of the stability and practicability of the remainder of the 'alignment. A combi-
SITE INVESTIGATIONS:GEOPHYSICS
195A
nation of landslide and erosion mapping along the proposed alignment and interpretation of air photographs led to the recommendation to abandon the remainder of the alignment and adopted an alternative route, considered to be more stable. -from Author
and also by the lack of detailed studies on the key locations, such as the dam itself. The dam suffered changes and rotations of the axis and excavation problems in the pressure tunnel, undoubtedly caused by mbLnterpretation of the local geology before construction. -from Author
944180 Mapping the Xigaze (Tibet) ophiolite complex with Landsat Thematic Mapper data J . P . Matthews & A. S. G. Jones, Journal of Himalayan Geology, 3(1), 1992, pp 97-101. Decorrelation stretch and band ratio image enhancement techniques have been applied to a Landsat Thematic Mapper (TM) scene covermg the remote Xigaze Ophiolite. Vegetation or soil cover is sparse in this region, so maps generated from satellite imagery can compliment information gathered from field surveys. From Landsat data, a map has been drawn of the main ophiollte massif which gives a more accurate overview of the distribution of lithologies than do previously published maps. -from Authors
944185 Some aspects of seismic hazard assessment in national and local leveb in Albania S. Kociaj, in: Comprehensive approach to earthquake disaster mitigation, ed A. V o g e l & others, (Vieweg; Progress in Earthquake Research & Engineering, Vol. 4), 1993, pp 85-117. Albania is one of the most active seismic countries in the Mediterranean Region. The seismic hazard assessment was based on three main elements: earthquake loci on the basis of seismological and geological data; maximum seismic energy to be released by the expected earthquake loci; and surface effects of this energy expressed either through strong ground motion parameters or through seismic intensities. Hazard maps for the whole country are described, and case studies of hazard assessment on a local level are presented. -G.E.Hodgson
Structural and geotechnical mapping 944181 An expert system approach to liquefaction analysis, part 1: development and implementation M.A. Chouicha & T. J. Siller, Computers & Geotechnics, 16(1), 1994, pp 1-35. This paper presents the development of the rule-based expert system, LIQUEFY, which evaluates the liquefaction potential of sites using several commonly accepted liquefaction evaluation methods. In this paper the issues in the design of the rule-based are addressed including: knowledge acquisition, knowledge representation, and system validation. LIQUEFY was developed for the personal computer and includes 470 rules, an explanation facility, and methods for handling uncertainty in input data and resulting conclusions. -Authors 944182 An expert system approach to liquefaction analysis, part 2: evaluation M . A . Chouicha, T. J. Siller & W. A. Charlie, Computers & Geotechnics, 16(1), 1994, pp 37-69. This is the second paper in a two-part series describing the development of LIQUEFY. The functional issues in designing LIQUEFY are presented: the implementation of five different methods for liquefaction hazards assessment and their incorporation into a unique framework for liquefaction evaluation. The system ~roups the implemented liquefaction methods into a preliminary and a final task. The performance of LIQUEFY is compared to pubfished case histories. -from Authors 944183 Understanding subsalt overpressure may reduce drilling risks J. O'Brien & I. Lerche, Oil & Gas Journal, 92(4), 1994, pp 28-34. An analysis of the subsalt physical environment can help engineers and geologists understand the potential for overpressure, which may lead to drilling problems during exptoration near salt sheets. Trapped hydrocarbons in format ions underlying salt sheets have become a promising exploration play in the Gulf of Mexico. Although subsalt targets share many characteristics with nonsalt targets, the presence of the salt body can influence the physical prol>erties of the target in a number of ways. Some of these factors may be critical to the success of a well and need to be addressed in the prospect evaluation and during well planning. -from Authors 944184 The Agua del Toro Dam, Mendoza, Argentina - a case of insufficient surface geology studies affecting underground excavations A . J . Amos, in: Comprehensive rock engineering. 1Iol. 5, ed J.A. Hudson, (Pergamon), 1993, pp 133-146. The Agua del Toro dam, pressure tunnel and powerhouse illustrate the effect of insufficient geological studies on the overall construction and represent a case which could have failed to deliver a very important source of energy to the Interconnected System or" Argentina during the 1970s. The [eology of the Agua del Toro project is by no means simple, being complicated by a rather bizarre stratigraphy .
RMM$ 31:4-,]
,
,
Geophysical techniques 944186
The geoeleeWical methods
exploration
in geophysical
M. S. Zhdanov & G. V. Keller, (Elsevier;Methods in Geochemistry and Geophyies, 31),ISBN (hardback) 0 A ~ 89678 3, price Dfl 375.00 (US$214.25), 1994, 873 pp, index. The first four chapters provide an introduction to electrical techniques in geophysics, covering rock and mineral properties and EM field behaviour. Chapters 5-7 deal with the standard geoelectrical techniques o~ direct current (DC), maj~,neto~Huric ( ~ ) , and controlled source electro.magneuc tt~M) memoas, t:napters ~-tl provide oetails on aspects of geoeiectrical theory common to all techniques, and are: modelling and simulation; insensitivity and sxmulation; practical aspects of data aquisition; and interpretation. Chapter 12 provides details of other methodologies, such as airborne EM surveys, borehole techniques , ground penetrating radar (GPR), and piezoelectric method (PEP). Chapter 13 gives details of 13 case studies using geoelectrical techniques from around the world, whilst the final chapter provides some generalisations for geoelectrical work. Two appendices provide details on mathematical conventions and FORTRAN programming. -R.Gower 944187 Geophysical testing for rock engineering K. Sassa, in: Comprehensive rock engineering. VoT. 3, ed J.A. Hudson, (Pergamon), 1993, pp 635-650. In this chapter, seismic testing within a borehole and between boreholes, and seismic tomography axe explained. The 'downhole method' is the most effective method to measure elastic wave velocities and attenuations in the borehole direction. By use of the 'cross-hole method', average velocities in the rock mass between sources and receivers are measured. Therefore, average pro])erties of the rock mass are obtained by this method. Setsratc tomography is the only technique able to obtain the two-dimensional distribution of propagation velocities and attenuation characteristics of elastic waves. -from Author 944188 Seismic imaging using micr0,earthquakes induced by hydraulic fracturing L.V. Block, C. H. Cheng, M. C. Fehler & W. S. Phillips, Geophysics, 59(1), 1994, pp 102-112. Seismic imaging using microearthquakes induced by ydraulic fracturing produces a three-dimensional (3-D), S-wave velocity model of the fractured zone, improves the calculated locations of the microearthquakes, and may lead to be.tter estimates of fracture plane orientations, fracture density, and water flow paths. Such information is important for predicting me amount of heat energy that may be extracted from geothermal reservoir. A fractured zone was created at the Los Alamns Hot Dry Rock Reservoir in north-central New Mexico within otherwise impermeable basement rock by injecting 21 000 m 3 of water into a borehole under high pressure at a depth of 3.5 kin. Induced