U.S. GEOLOGICAL SURVEY CIRCULAR 987 

The Use of Surface Geophysical Techniques 

To Detect Fractures in BedrockAn Annotated Bibliography 

Prepared in cooperation with 

the U. 5. Department of Energy 

The Use of Surface Geophysical Techniques 

To Detect Fractures in BedrockAn Annotated Bibliography 

By Mark Ro lewis and FoP o Haeni 

U.S. GEOLOGICAL SURVEY CIRCULAR 987 

Prepared in cooperation with 

the U.S. Department of Energy 

1987 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Library of Congress Cataloging-in-Publication Data 

Lewis, Mark R. 

The use of surface geophysical techniques to detect 

fractures in bedrock. 

(U.S. Geological Survey circular; 987) 

•Prepared in cooperation with U.S. Department of 

Energy." 

Supt. of Docs. no.: I 19.4/2:987 

1. Rocks-Fracture--Bibliography. 2. ProspectingGeophysical methods-Bibliography. 1. Haeni, 

F.P. II. Title. Ill. Series: U.S. Geological Survey 

circular; 987. 

Z6033.R62L49 1987 [QE604] 016.5518 86-600275 

Free on application to the Books and Open-File Reports Section, 

U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 
CONTENTS 

Page 

Conversion factors and abbreviations ------------------------------------- ------ ------- IV 

Abstract--------------------------------------------------------------------------- 1 

Introduction------------------------------------------------------------------------ 1 

Purpose and scope -- ------------ -- ----- ---- ----- ------- -- ----- --------- ---- --- -- 2 

Annotated references ---------------------------------------------------------------- 2 

Foreign language references ------------ ------------ -- ------------ --------- ---- ------- 11 

Summary-------------------------------------------------------------------------- 12 

References cited--------------------------------------------------------------------- 13 

cnossary --------------------------------------------------------------------------- 13 

Ill 
CONVERSION FACTORS AND ABBREVIATIONS 

INCH-POUND TO METRIC UNITS 

Multiply inch-pound unit By To obtain metric unit 

Length 

foot (ft~ 0.3048 meter (m) 

mile (mi 1.609 kilometer(km) 

Area 

square mile (mi2) 2.590 square kilometer (km2) 

Resistivity 

Cllm-feet (ohm-ft) 0.3048 ohm-meter (ohm-m) 

Mass 

pound (lb) 0.4536 kilogram (kg) 

METRIC TO INCH-POUND UNITS 

Multiply metric unit By To obtain inch-pound unit 

Length 

meter (m~ 3.281 foot (ft) 

kilometer (km 0.6214 mile (mi) 

Area 

square kilometer (km2) 0.3861 square mile (mi2) 

Resistivity 

ohm-meter (ohm-m) 3.281 ohm-feet (ohm-ft) 

Mass 

kilogram (kg) 2.205 pound (lb) 

IV 
The Use of Surface Geophysical Techniques to Detect 

Fractures in Bedrock-An Annotated Bibliography 

By Mark R. Lewis and F.P. Haeni 

Abstract 

This annotated bibliography compiles references about the 

theory and application of surface geophysical techniques to locate 

fractures or fracture zones within bedrock units. Forty-three publications are referenced, including journal articles, theses, conference proceedings, abstracts, translations, and reports prepared by 

private contractors and U.S. Government agencies. Thirty-one of 

the publications are annotated. The remainder are untranslated 

foreign language articles, which are listed only as bibliographic 

references. 

Most annotations summarize the location, geologic setting, 

surface geophysical technique used, and results of a study. A few 

highly relevant theoretical studies are annotated also. 

Publications that discuss only the use of borehole geophysical 

techniques to locate fractures are excluded from this bibliography. 

Also excluded are highly theoretical works that may have little or no 

known practical application. 

INTRODUCTION 

The need for cost effective methods to locate 

individual fractures or fracture zones in bedrock has 

increased in recent years. Such methods are critical to 

a wide variety of hydrogeologic applications, one of the 

most important of which is hazardous-waste management. Bedrock fractures provide a conduit for the 

migration of waste from disposal areas to household or 

municipal wells. Information about fractures is needed 

to predict the movement and fate of contaminants. 

Surface geophysical techniques have been used successfully to locate fractures and to describe their geometry. 

Another hydrologic application is the evaluation 

of the suitability of various geologic structures or sites 

for nuclear-waste repositories. Plutons in continental 

shield areas and salt domes have been considered for 

this use because of their typically lo.v primary permeability and porosity and because of their relative tectonic 

stability (Wright and others, 1980; Mair and Green, 

1 

1981; Soonawala and Dence, 1981; Green and Mair, 

1983; Bazinet and Legault, 1985). Granitic plutons 

commonly contain fractures or fracture systems that 

must be studied to prevent the migration of radioactive 

waste. 

Fractured rock is a potential source of ground 

water in many parts of the wor kl. Most bedrock wells 

depend on fractures for recharge and perme<iJility. 

Information on fracture configuntion can be used to 

help locate wells and to reduce the chances of drilling 

dry holes. 

Many other activities require information on 

bedrock fractures. Fractures play a role in the stability 

of mines and tunnels (Stephansson and others, 1979), 

need to be considered in developing geothermal energy 

systems (Aamodt and others, 1977), and are an important factor in the in-place mining of uranium, copper, 

or other minerals by chemical leaching. Fractures 

within bedrock units typically are evalucted by surficial 

mapping of outcrops, by interpreting lineations on 

aerial or satellite photos, or by analyzing lithologic 

samples from boreholes. The usefulness of these methods for fracture-detection studies is limited. Fractures 

are not always continuous throughout a body of rock, 

and those present at depth may h£Ne no surface ~pression. In addition, unconsolidated sediment or artificial 

fill commonly covers the bedrock surface and limits the 

use of surficial-mapping techniques. Drilling is expensive and must be supplemented by other indirect methods. 

The increased demand for information on fractures within a rock body, and the limited usefulness of 

traditional data-collection methods, has led to the development and use of new methods for gc:thering that 

information. Among the most promising developments 

in this area is the introduction of geophysical methods 

to locate and evaluate bedrock fractures. 
Surface and borehole geophysical methods both 

have been successfully used to locate and characterize 

fractures in bedrock, although this report is concerned 

only with surface geophysical methods. A recent review 

of literature relating to borehole geophysical methods is 

presented by Paillet (1985). 

Surface geophysical methods are numerous and 

varied, but they all measure the response of subsurface 

materials and their interstitial fluids to a naturally or 

artificially generated signal (sound, electrical current, 

and so forth). Interpretation of this response provides 

information about the subsurface materials and the 

fluids within them. These methods have several advantages over traditional mapping methods. Geophysical 

surveys generally are less expensive than drilling programs and, when conducted in conjunction with an 

exploratory drilling program, can reduce the number of 

drill holes needed by placing drill holes more effectively. Surface geophysical surveys also create little or 

no environmental disturbance. Therefore they may be 

used in areas where drilling is not allowed or is 

impractical. Some surface geophysical techniques also 

can be used to examine bedrock covered by unconsolidated material. 

PUR POSE AND SCOPE 

This bibliography is a compilation of references 

for literature describing the theory and application of 

surface geophysical methods to the problems of locating 

fractures or fracture zones in bedrock. Annotations of 

most references are provided to assist the reader in 

evaluating the relevance of the articles to a particular 

hydrogeologic setting. 

Several sources were consulted in the compilation 

of this bibliography. Initially, a computerized search 

was made of the National Technical Information Service (NTIS) and GeoRefl data bases. The NTIS data 

base is the computerized equivalent of the U.S. Government Reports and Announcements Index. As of 

January 1981, the NTIS data base contained about 

700,000 references to U.S. Government technical and 

research reports and journal articles, dating back to 

1970. GeoRet a product of the American Geological 

Institute, is a compilation of several bibliographies, 

including the "Bibliography of North American Geology," "Bibliography and Index of Geology Exclusive of 

North America," "Bibliography of Theses in Geology," "Geophysical Abstracts," and "Bibliography 

and Index of Geology." It compiles and lists articles 

1

Any use of trade names and trademarks in this publication 

is for descriptive purposes only and does not constitute endorsement by the U.S. Geological Survey. 

2 

from over 4, 500 international journals and conference 

proceedings, books, maps, dissertations, and other 

publications dating back to 1785. In addition, a manual 

search of the previous 5 years of issues of the "Bibliography and Index of Geology" was performed, and 

additional references were found. 

All relevant publications, except for a few untranslated foreign-language articles, were obtained for 

further evaluation. The reference lists of these publications were checked for additional references. This 

process was supplemented by a monthly check of the 

current "Bibliography and Index of Geology" to reference those publications indexed since the computer 

literature search. Several authors also were contacted to 

check on the current status of their work and on new 

publications. 

Publications that discuss only borehole 

geophysical methods were excluded, as were highly 

theoretical articles having little or no known practical 

application. Only those articles that describe a new 

technique, a new variation of an existing technique, or 

a new use of an existing technique under novel field 

conditions were included in this bibliography. 

To avoid the use of awkward converted units of 

measurement and to reduce the possibility of confusion, the units used in the original sources have been 

preserved in the annotations. A table of factors for 

converting inch-pound units to metric units and vice 

versa is included in this report for the reader's convenience. 

This compilation includes several foreign language references that were available in fully translated 

form. These have been annotated and are included in 

the main body of this report. Those articles for which 

full translations could not be obtained were not annotated but are included in a section at the end of this 

report. 

ANNOTATED REFERENCES 

Anderson, D.L., Minister, B., and Cole, D., 1974, 

The effect of oriented cracks on seismic velocities: 

Journal of Geophysical Research, v. 79, no. 26, 

p. 4011-4015. 

This article presents a theory on the effects 

of fluid-filled fractures having a preferred orientation on seismic velocities within rock. The theory assumes that the fractures within a body of 

rock, and the mineral grains that constitute that 

rock, are randomly oriented. The authors conclude that seismic velocities within fractured rock 

are controlled by (1) the elastic properties of the 

matrix, (2) porosity of the rock, (3) aspect ratio of 
the fractures, ( 4) bulk modulus of the pore fluids, 

and (5) the direction of seismic-wave propagation. 

Seismic velocities are decreased in a direction 

normal to the plane of the cracks. 

Bamford, D., and Nunn, K.R., 1979, In-situ seismic 

measurements of crack anisotropy in the 

Carboniferous limestone of northwest England: 

Geophysical Prospecting, v. 27, p. 322-338. 

P-wave velocity anisotropy, which is defined 

as the variation in seismic P -wave velocity with 

direction, was determined from P-wave velocities 

measured by using 12-channel seismic-refraction 

equipment in Carboniferous limestone at three 

sites in northwestern England. The limestone, 

which is partly overlain by a few meters of drift, 

contains three dominant vertical joint sets having 

known orientations. 

Field observations consisted of linear profiles, fan shots, and offset shots. Directional variations in P-wave velocity were correlated with 

"previously mapped orientations of joints." The 

authors suggest that the use of seismic-reflection 

techniques might allow measurement of velocity 

anisotropies over a wider range of conditions than 

that provided by refraction techniques. 

Bazinet, Robert, and Legault, Jean, 1985, Scalar 

audiomagnetotellurics: A tool in the evaluation of 

nuclear waste disposal sites: Society of Exploration Geophysicists Annual International Meeting, 

55th, Washington, D.C., 1985, expanded 

abstracts of the technical program with author's 

biographies, p. 149-150. 

The scalar audiomagnetotelluricmethod can 

be used to measure indirectly the water content of 

fractured or porous rock by measuring the rock's 

apparent resistivity. This technique is a simplified 

version of the conventional audiomagnetotelluric 

method. At any given frequency, the technique 

measures only a single pair of the electrical and 

magnetic components of a naturally occurring 

electromagnetic (EM) field. By doing this, the 

expression for apparent resistivity is reduced from 

a complex tensor to a scalar equation; this change 

simplifies the interpretation process. Because the 

depth of penetration varies as a function of frequency, a vertical profile can be constructed. 

This technique was used to locate waterfilled fractures within a pluton at a potential 

nuclear waste-disposal site on the Canadian Shield 

3 

in Ontario. Two rock layers were distinguished, 

on the basis of differing apparent resistivities. The 

top layer, which is relatively conductive, was interpreted to be a combination of glacial overburden 

and the fractured top of bedrock. This layer is 

underlain by highly resistive material, which was 

interpreted to be nonfractured bedrock. The article does not mention whether this model was 

checked against test-hole or surface-mapping 

data. 

The authors list two advantages of this technique over other surface geophysical techniques 

for detecting fractures. (1) Only water-filled fractures will be detected; those filled with quartz or 

other minerals will be ignored. (2) Data from deep 

fractures can be obtained. 

Crampin, Stuart, McGonigle, Robert, and Bamford, 

David, 1980, Estimating crack parameters from 

observations of P-wave velocity anisotropy: 

Geophysics, v. 45, no. 3, p. 345-360. 

The authors mapped fractures in shallow 

Carboniferous limestone in northwestern England 

by reinterpreting seismic-refraction data obtained 

by Bamford and Nunn (1979). The data consisted 

of reversed seismic profiles up to 70 m long and 

fan shots having 40-m radii. The authors concluded that (1) information about fracture properties may be obtained by inverting velocity anisotropy data; (2) variations in velocity reflect 

different degrees of saturation within cracks; (3) if 

the dip of fractures can be assumed, then "inversion of only the P-wave velocity anisotropy can 

model the complete velocity variation of all body 

waves in the structure by means of effective anisotropic elastic constants"; and ( 4) polarization 

anomalies observed for synthetic seismograms 

indicate wave "propagation through cracked or 

anisotropic structures." 

Denahan, B.J., and Smith, D.L., 1984, Electrical 

resistivity investigations ofpotential cavities underlying a proposed ash disposal area: Environmental 

Geology and Water Science, v. 6, no. 1, p. 45-49. 

A direct current (D.C.) resistivity survey 

was performed to define solution cavities in fossiliferous Eocene limestone at a proposed ashdisposal site in Florida. The limestone, which is 

over lain by up to 5 ft of unconsolidated material, 

contains solution cavities having average diameters 

of 1 to 5 ft. The survey was performed on a 1,200-
by 2, 600-ft grid by using a Wenner array having 

constant electrode spacing. At some locations, 

Wenner array depth soundings having systematically increased electrode spacings also were performed. Several zones of low apparent resistivity 

were detected, and they were attributed to fluidfilled solution cavities. Results of resistivity surveys were checked by drilling 54 test borings, 24 

of which coincided with the resistivity stations. 

The authors reported an 86-percent agreement 

between data collected during drilling and interpretations of resistivity measurements. 

Frolich, R K., 1986, Size estimates of buried fracture 

zones with geophysical methods [abs.]: Geological Society of America, Abstracts with Programs, 

v. 18, no. 1, p. 17. 

Gravity and magnetic surveys were used to 

locate fracture zones in crystalline rock in Rhode 

Island. The author suggests that fracture zones 

commonly are found beneath "valleys and topographic lows," because fractured rock is easily 

eroded. The gravity survey located gravity lows in 

the area of a lineament and in a river valley. These 

lows are interpreted as representing fracture zones 

that are 500 m wide and 1 to 4 km deep and that 

have porosities ranging from 2 to 4 percent. He 

cautions that these figures are approximations 

"indicating the order of magnitude rather than the 

precise geometry of fracture zones." 

The magnetic surveys were performed over 

buried glacial stream channels. The surveys 

detected "negative anomalies which can be 

explained by non-magnetic gaps" associated with 

fracture zones. These anomalies were detectable 

by using station spacings of 100ft, in areas having 

"extremely low and irregular levels of magnetization." Information from the magnetic surveys was 

correlated with "outcrop evidence and magnetic 

susceptibility measurements on hand samples." 

Goryunov, I. I., 1972, Ulelnoe elektricheskoe soporotivlenie treschinovatoi parody [Electrical resistivity of fractured rock]: U.S. Bureau of Mines 

Report TR-3-72, 15 p. [Translation of Prikladnaya Geofizika (USSR), no. 38, p. 173-179, 

1964, Law, D. A, and Brown, J. W., translators.] 

This paper describes the use of matrix algebra to derive a theoretical relation between the 

geometry of fractures within a rock and that rock's 

electrical resistance. The author made several 

4 

simplifying assumptions. (1) Three randomly oriented fracture systems are assumed to cut an 

otherwise uniform, isotropic body of rock. (2) 

Each fracture system was assumed to consist of 

parallel fractures that extended indefinitely in two 

dimensions and that had identical width and regular spacing. (3) The fractures were assumed to be 

filled with a material having a resistivity lower than 

that of the surrounding bedrock. 

The method can be applied in a forward or 

inverse direction. The resistance tensor of the 

fractured rock can be calculated by using the 

resistivity of the rock matrix and of the fluid filling 

the fractures, as well as by the geometry of the 

fractures. Conversely, the density and width of 

fractures can be determined if the resistance of 

fractured rock is known. 

The width and density of fractures at a depth 

of approximately 2, 300 m within a borehole were 

measured by using the methods outlined above. 

Resulting values were found to correspond with 

measurements made by microscopic examination 

of thin sections of the borehole core. The article 

did not discuss field methods used to make these 

measurements. 

Green, AG., and Mair, J.A, 1983, Subhorizontal 

fracture zones in a granitic pluton: Their detection 

and implications for radioactive waste disposal: 

Geophysics, v. 48, no. 11, p. 1428-1449. 

This study used high-resolution, seismicreflection techniques to locate horizontal fracture 

zones at depths up to 800 m within a granitic 

pluton on the Canadian Shield in southeastern 

Manitoba. The pluton is overlain by a discontinuous layer of highly conductive till having a maximum thickness of about 25 m. Previously, the till 

had hindered electromagnetic and resistivity measurements at a nearby site (Soonawala and Dence, 

1981). 

Data were collected along five profiles over a 

4. 8-km2 area. Small construction-type earth tampers were used as a sound source for three of the 

profiles; explosives were used in the other two. 

The receiving setup consisted of 24 arrays of 9 

geophones each. Each group of geophones was 

deployed along a 10- to 20-m line having a 10- to 

20-m interval between arrays. 

The surveys revealed two gently dipping 

reflectors, which were interpreted as fracture 

zones. Holes drilled along the profiles intersected 

major fracture zones at depths of 300 to 600 m. 

This observation was in close agreement with the 
depths predicted from the seismic profiles. 

Borehole-televiewer examination of one drill hole 

confirmed the shallow dip of the fractures. 

Harmon, E.J., 1984, Investigation of a previously 

unexplored basaltic aquifer using complementary 

geophysical methods, in Nielsen, D.M., and 

Curl, M., eds., National Water Well Association/D. S. Environmental Protection Agency Conference on Surface and Borehole Geophysical 

Methods in Groundwater Investigations, San 

Antonio, Texas, 1984, Proceedings: Worthington, Ohio, National Water Well Association, p. 

273-287. 

This investigation focused on the Servilleta 

furmation -a series of Pliocene basalt flows in 

southern Colorado. The basalt flows, which range 

from 250 to 370 ft in thickness, are interbedded 

with thin layers of sand, gravel, clay, and minor 

ash flows. Major north-south-trending normal 

faults and associated fracture systems cut the Servilleta and produce characteristic horst and graben 

structures. Reworked sand, gravel, and clay 

deposits, which average 250 to 300ft in thickness, 

overlie the basalt. 

Various geophysical surveys were performed in the area as part of an exploration 

program to find a source of water for a coal-slurry 

pipeline. The results of each survey were crosschecked against the results of the other surveys 

and against data obtained by test drilling, aquifer 

testing, and conventional geologic mapping. 

Data from a 3, 800-ft-long seismicrefraction line were used to locate a large, previously mapped fault. This technique was less successful with smaller faults and with their 

associated fracture zones. The authors suggest 

that the refraction survey may have been "too 

limited" to detect the smaller scale faults and 

fracturing. Total-field ground magnetometer surveys, however, were more successful in locating 

these small-scale features. Magnetometer-survey 

results were confirmed by test drilling. Gradientarray and dipole-dipole resistivity surveys both 

were able to clearly delineate the smaller scale 

faults. 

Huntley, D.J., and Misher, H.M., 1984, Relationship 

between permeability and electrical resistivity in 

granular and fractured rock aquifers, in Nielsen, 

D.M., and Curl, M., eds., National Water Well 

Association/D. S. Environmental Protection 

5 

Agency Conference on Surface and Borehole 

Geophysical Methods in Groundwater Investigations, San Antonio, Texas, 1984, Proceedings: 

Worthington, Ohio, National Water Well Association, p. 18-36. 

This survey was part of a project designed to 

examine the relation between electrical conductivity and permeability in fractured rock and unconsolidated aquifers. Permeabilities of fracturedrock aquifers, determined by pumping tests, were 

compared with permeabilities determined by 

dipole-dipole resistivity surveys. Twelve sites were 

examined, and 24 true-resistivity cross sections 

were constructed. "Distinctive vertical, low resistivity anomalies through, or immediately adjacent 

to" well sites were interpreted as representing clay 

weathering within fracture zones . .At three well 

sites, clay weathering zones recorded in borehole 

logs were not detected by the resistivity survey. 

Fractures in the remaining four well sites intersect 

relatively unweathered rock. The authors suggest 

that the presence of such highly conductive clay 

minerals in the weathered zones "strongly affects 

the apparent formation factor in fractured rock." 

Formation factor is defined as the ratio of the 

resistivity of a fractured rock to that of the fluid that 

saturates the rock. 

Imse, J.P., and Levine, E.N., 1985, Conventional and 

state of the art geophysical techniques for fracture 

detection: National Water Well Association Annual 

Eastern Regional Groundwater Conference, 2d, 

Portland, Maine, 1985, Proceedings, p. 18-36. 

Microgravity, electrical resistivity, groundpenetrating radar, and seismic-refraction techniques were used in an attempt to delineate fracture zones within flat-lying carbonate rocks at a 

site in northern New York. Bedrock in the area is 

characterized by extensive development of karst 

topography and is overlain by topsoil, weathered 

bedrock, and artificial fill from 0 to more than 30 

ft in thickness. 

Seismic-refraction and ground-penetrating 

radar were the most successful techniques used. 

Information from these methods was independently verified by subsequent mapping. 

The seismic surveys were conducted by 

using a 24-channel seismograph having 250-ft 

spreads and a shotgun-type sound source. Some 

fracture zones were indicated on the seismic profiles as distinct low-velocity zones. In areas where 

individual fractures are separated by intact rock, 
the fractures were recognized as directional variations in seismic velocities. 

If a refraction line paralleled the trend of a 

fracture system, much of the seismic energy was 

conducted directly to the geophones through the 

intact rock between the fractures. Such a fracture 

system had relatively little effect on seismic velocities. If a line was perpendicular to the fracture 

trend, however, seismic energy had to travel across 

fracture openings to reach the geophones. This 

effect lowered seismic velocity in that direction. 

Ground-penetrating radar data were collected by using a 300-MHz antenna. The data 

were reportedly of sufficient quality to allow interpretation 'Nith no further processing. Fracture 

zones were marked on the radar record as 

hyperbola-shaped reflections. Such features were 

produced when the radar signal was reflected from 

the sides of the fracture as the radar unit passed 

overhead. 

Jammallo, J. M., 1984a, Delineation of bedrock fracture trace zones by remote sensing and magnetics 

and their hydrogeologic implications: Burlington, 

Vt., University of Vermont, unpublished master's 

thesis, 274 p. 

This study integrated aerial photointerpretation with a surface geophysical survey to define 

fracture zones in northern Vermont. The study 

area, which is underlain by metamorphic rock, 

has a thin mantle of till at higher elevations and 

stratified drift and alluvial sand in valleys. Fractures, which initially were identified as linear 

features on aerial photographs, were located by a 

systematic magnetometer survey. To confirm the 

results of this work, joints were mapped at outcrops. 

Magnetic anomalies were classified according to their origin to separate those caused by 

fracture zones from those resulting from magnetic 

mineralization or cultural interference. Most of 

the photolineaments caused by fracture zones were 

found to have strong positive magnetic anomalies. 

The azimuth of each anomaly was defined in the 

field by performing a continuous circular survey 

about the point of greatest intensity. Orientations 

thus determined were found to correspond to the 

directions of the photolineaments within ± 10°. 

The joint outcrop mapping data were not analyzed 

statistically, although "slight positive correlation" 

seemed to occur between the areas of high joint 

density noted in the field and areas of "fracture 

6 

trace concentration" defined by magnetic and photographic methods. 

Jammallo, J.M., 1984b, Use of magnetics to enhance 

identification of bedrock fracture trace zones for 

well locations: National Water Well Association 

Annual Eastern Regional Groundwater Conference, 1st, Newton, Mass., 1984, Proceedings, p. 

273-287. 

This talk summarized the results reported in 

greater detail by Jammallo (1984a). 

Kerschner, D. R., 1980, The location of fractured 

zones in bedrock by earth resistance, seismic 

refraction, and soil temperature surveys [ abs. ]: 

Geological Society of America, Abstracts with 

Programs, v. 12, no. 2, p. 45. 

This study used seismic-refraction, resistivity, and subsurface-temperature measurements to 

locate fractures in bedrock overlain by till. Fracture zones were denoted as areas of lowered seismic velocity and resistivity. In addition, the temperature 4ft below land surface, near the fracture 

zone, was more stable over the course of the 

experiment than that in the surrounding area. 

This effect was attributed to moist material within 

the fracture zone acting as a heat sink. The results 

from each of the three methods were in close 

agreement. 

Kirk, K.G., and Rauch, H.W, 1977, Location of 

fracture zones by electrical resistivity surveying 

with the tri-potential resistivity technique [ abs.]: 

Eos, Transactions of the American Geophysical 

Union, v. 58, no. 6, p. 392. 

The tri-potential resistivity technique integrates data from three commonly used resistivity 

sounding arrays: CPPC (current-potentialpotential-current electrode arrangement), CPCP 

(current-potential-current-potential electrode 

arrangement), and CCPP (current-currentpotential-potential electrode arrangement). This 

method was applied to locate fractures in shalesandstone rocks at an underground coal gasification plant in West Virginia. Fracture zones and 

their corresponding resistivity anomalies were 

delineated by plotting apparent resistivities and 

percentage residual resistivities. Percentage residual resistivity is equal to (RcrPc-RccPP-RcPcP) X 
(100/RcPPc), where RcPPc is equal to apparent 

resistivity measured by the current-potentialpotential-current electrode arrangement, RccP P is 

equal to apparent resistivity measured by currentcurrent-potential-potential electrode arrangement, 

and ReP cp is equal to apparent resistivity measured by the current-potential-current-potential 

electrode arrangement. 

Six fracture zones were located, four of 

which correspond to mapped photolineaments. 

The percentage-residual-resistivity measurement 

was reportedly able to detect the location, surface 

width, and minimum depth of the fracture zones. 

Leonard-Mayer, P.J., 1984a, A surface resistivity 

method for measuring hydrologic characteristics 

of jointed formations: U.S. Bureau of Mines 

Report of Investigations 8901, 45 p. 

The azimuthal-resistivity method may be 

used to determine the strike direction of the dominant set of fractures or joints within bedrock. In 

this technique, Wenner, Lee, and Wenner-Lee 

arrays are rotated about a fixed point, and currentpotential readings are taken at fixed intervals of 

rotation (commonly 10° ). The resulting apparent 

resistivity readings, when plotted on polar coordinate axes, approximately define an ellipse. Strike 

direction of fractures and joints may be determined from the graph by noting directions of high 

apparent resistivity. This method assumes that 

joints or fractures may be treated as thin layers 

having resistivities that contrast with those of the 

surrounding rock. 

This method was applied in carbonate rocks 

at four sites in Minnesota and Wisconsin and in 

shale at a coal mine in Pennsylvania. Wenner and 

Wenner-Lee arrays were used in all surveys. 

Because structural patterns in the rocks at each of 

the sites are known from previous work, results of 

the surface geophysical surveys could be confirmed. The Wisconsin sites also were examined 

in a separate study by Taylor (1982, 1984), and 

the Minnesota site was the subject of a similar 

survey by Technos, Inc. (1985). 

The resistivity surveys were notably successful in locating water-filled joints and fractures 

but could not locate those filled with air. Water 

within joints and fractures creates a zone of 

increased conductivity (decreased resistivity). In 

air-filled fractures, the direction of maximum 

apparent resistivity varies over time. This effect is 

attributed to differential drying of the fractures in 

the rock. At the Pennsylvania site, survey results 

7 

were in good agreement with fracture orientation, 

whereas "the effect of joints was much less obvious." A horizontal-resistivity survey was run 

along the length of a valley at this site by using a 

Wenner-Lee array having a constant survey orientation. Zones of low apparent resistivity encountered along this line are thought to represent zones 

of increased fracturing. 

Water flowing from a river through fractures 

and into the mine at the Pennsylvania site caused 

measurable streaming potential. Drops in the 

streaming potential were found to correspond well 

with fracture and joint strike determined by the 

azimuthal resistivity method. 

Leonard-Mayer, P.J., 1984b, Development and use of 

azimuthal resistivity surveys for jointed formations, in Nielsen, D.M., and Curl, M., eds., 

National Water Well Association/D. S. Environmental Protection Agency Conference on Surface 

and Borehole Geophysical Methods in Groundwater Investigations, San Antonio, Texas, 1984, Proceedings: Worthington, Ohio, National Water 

Well Association, p. 52-91. 

This talk summarized the results reported in 

greater detail by Leonard-Mayer (1984a). 

Mair, J.A, and Green, AG., 1981, High resolution 

seismic reflection profiles reveal fractures within a 

homogeneous granite batholith: Nature, v. 294, p. 

439-442. 

This paper summarizes the results reported 

later in greater detail by Green and Mair (1983 ). 

Mallik, S.B., Bhattacharya, D.C., and Nag, S.K., 

1983, Behaviour of fractures in hard rocks-A 

study by surface geology and radial VES method: 

Geoexploration, v. 21, p. 181-189. 

The radial VES (vertical electrical sounding) method was employed to detect fractures 

within amphibolites, metabasics, and granites at 

five sites in West Bengal, India. This study 

employed a Schlumberger array, which was 

rotated about each sounding station. Apparentresistivity measurements were made at 45° intervals and were plotted on polar diagrams. In a 

perfectly isotropic medium, the resulting plot 

would be circular. Apparent resistivities from 

these sites plotted as ellipses; the ellipsoid plots 
indicate anisotropic conditions and rock fractures. 

The orientation of the major axis of an ellipse 

indicates the strike direction of the corresponding 

fracture. 

To confirm the results of the VES survey, 

fracture orientations were mapped at about 100 

outcrops. The results were plotted on an equalarea net and were found to be in good qualitative 

agreement with the VES data. Both methods 

detected fracture systems striking in similar directions. The paper does not discuss the specific 

quantitative accuracy of the VES technique. 

Moore, D.L., and Stewart, M. T., 1980, Geophysical 

signatures to fracture traces in west-central Florida [ abs.]: Geological Society of America, 

Abstracts with Programs, v. 12, no. 4, p. 202. 

Infrared aerial and satellite photographs 

were used to locate fracture traces in carbonate 

rocks in west-central Florida. The fracture zones 

are approximately 1 to 3 km long and 200 to 300 m 

wide. The traces were successfully located in the 

field by using seismic-refraction and electricalresistivity techniques. Magnetic surveys were 

unsuccessful, and highly accurate gravity surveys 

were found to require" further investigations ... to 

determine their practical value" in this application. 

Ogden, AE., and Eddy, P.S., Jr., 1984, The use of 

tri-potential resistivity to locate fractures, faults 

and caves for siting high yield water wells, in 

Nielsen, D.M., and Curl, M., eds., National 

Water Well Association/U.S. Environmental Protection Agency Conference on Surface and 

Borehole Geophysical Methods in Groundwater 

Investigations, San Antonio, Texas, 1984, Proceedings: Worthington, Ohio, National Water 

Well Association, p. 130-149. 

In the tri-potential resistivity method, three 

different current-potential readings are taken at 

each survey station. In addition to the standard 

CPPC array, the CCPP and CPCP arrays are 

moved in a lateral traverse having a constant 

electrode spacing throughout the traverse. 

This method was applied to locate fractures, 

solution cavities, and faults in carbonate rock in 

Arkansas. Fractures and solution cavities located 

by resistivity surveys were confirmed either 

directly by well logs or by observation of outcrops 

or indirectly by noting unusually productive wells 

in the vicinity of the fractures. The following 

8 

general relations were observed in this study: (1) 

Water-filled fractures and caves caused apparent 

resistivity to decrease in the CPPC and CPCP 

configurations and to increase in the CCPP configuration. (2) Air-filled fractures caused apparent 

resistivity to increase in the CPPC and CPCP 

configuration and to decrease in the CCPP configuration. (3) Air-filled caves caused an increase in 

apparent resistivity in all three configurations. The 

authors note that this technique may be used to 

detect fracture zones not mappable from aerial 

photographs. 

Palmer, S.P., 1982, Fracture detection in crystalline 

rock using ultrasonic reflection techniques: Berkeley, Calif., University of California, Berkeley, 

PhD thesis, 338 p. 

This article describes the use of 

high-frequency, seismic-reflection techniques to 

detect fractures within granite in field and laboratory settings. Measurements were made by using 

both P- (compressional) and SH- (horizontally 

polarized shear) waves. 

The laboratory experiments used small 

piezoelectric plates as ultrasonic sources and 

receivers. These plates were attached to the surface of experimental specimens by epoxy. The 

sound sources were excited with a step-voltage 

pulse. The resulting seismic waves were transmitted through the granite slab to the receivers. 

Signals from the receivers were processed by 

using a variety of techniques, including deconvolution and direct-array synthesis. 

Fractures present within the rock were 

detected as hyperbola-shaped SH-wave reflections. Dip angles of the fractures were calculated 

from SH-wave velocity, source-receiver separation 

distance, and SH-wave arrival times at two separate receivers. Interference from Rayleigh waves 

made detecting fractures with unprocessed P-wave 

signals difficult. The author suggests that both Pand SH-wave reflection measurements are needed 

to reliably determine whether fractures are filled 

with air or water. 

Field work was performed in a granite 

quarry in Madera County, Calif. Only SH waves 

were measured. The piezoelectric source and 

receivers were attached to the rock surface by 

1/2-inch bolts and a piece of lead foil coated on 

both sides with a sticky resin. The rock surface in 

the contact area was ground smooth to provide 

better acoustical coupling. Because of its bulk, the 

signal processing equipment could not be brought 
into the field. Instead, receiver signals were 

recorded on tape in analog form and were later 

played back and processed in the laboratory. 

SH waves were found to be totally reflected 

by fractures. This phenomenon prevented the 

detection of fractures beyond the one nearest to the 

SH-wave source. In addition, water saturation 

increased attenuation of SH waves. These effects 

were confirmed by further laboratory experiments. 

Park, Stephen, and Simmons, Gene, 1982, Crack 

induced velocity anisotropy in the White Mountains, New Hampshire: Journal of Geophysical 

Research, v. 87, no. 84, p. 2977-2983. 

Azimuthal variations in seismic P-wave 

velocity can be used to detect fractures in rock. 

Such variations may be observed by using a series 

of rotated seismic lines that radiate from a common 

endpoint. This technique was tested at four sites in 

the White Mountains of New Hampshire. The 

sites are underlain by granite, quartz syenite, and 

volcanic rocks having discontinuous overburden 

up to 3 m in thickness. Measurements were made 

by using a 12-channel seismograph. Geophone 

spacing was 6 m, and rotation between lines was 

20°. A 70-kg dropped weight and a sledgehammer served as sound sources. 

Fracture orientations measured by this 

method were within 30° of the actual orientations 

measured directly. The authors suggest that this 

relatively large discrepancy may have been caused 

by microcracks having a preferred orientation 

different from that of the main fracture system. 

This method was unable to distinguish the effects 

produced by the fractures from those related to the 

much smaller microcracks. The authors suggest 

that better results might be obtained by combining 

measurements of S-wave velocity anistropy with 

measurements of P-wave velocity anisotropy. 

Soonawala, N. M., and Dence, M. R., 1981, Geophysics in the Canadian nuclear waste program -A 

case history: Society of Exploration Geophysicists 

Annual International Meeting, 51st, Los Angeles, 

Calif., 1981, Proceedings, p. 83-98. 

A variety of airborne, ground-based, and 

borehole-geophysical surveys was performed at 

the planned site of an underground laboratory in a 

granitic pluton in the Canadian Shield in Canada. 

The objectives of the surveys were to define the 

9 

size of the pluton, to identify and locate fractures 

and other structural discontinuities within it, and 

to predict the pluton's long-term tectonic stability. 

A separate, high-resolution, seismic-reflection 

survey also was performed at a nearby site within 

the pluton (Mair and Green, 1981; Green and 

Mair, 1983). 

Fractures visible in outcrops within a 3. 8-

km2 area were mapped. A strong correlation was 

noted between the mapped fracture traces and 

results of the ground-based gradient resistivity 

survey. Areas having low-fracture density were 

found to coincide with areas of high resistivity 

(greater than 10,000 ohm-m). Areas having highfracture density coincided with resistivity lows 

(less than 2,000 ohm-m). 

Although highly conductive overburden hindered very low frequency (VLF) surveys, some 

trends on the VLF map may indicate major vertical fracture zones. These trends agree "reasonably well" with mapped fracture traces and results 

of resistivity surveys. 

Stephansson, Ove, Lande, G., and Bodare, A, 1979, 

A seismic study of shallow jointed rocks: International Journal of Rock Mechanics and Mining 

Sciences & Geomechanics Abstracts, v. 16, p. 

319-327. 

This paper develops a theory for seismicwave propagation at shallow depths in jointed 

rocks. According to the theory, point-source elastic waves will propagate around the tip of an open 

joint, where the waves will be refracted according 

to Huygen' s principle. This propagation causes 

the velocity curve to be displaced along the time 

axis of a traveltime diagram. The resulting intercept time is used with wave velocity and joint 

spacing to calculate depth to the joint. 

The theory was applied to determine the 

depth of artificial joints in concrete-block laboratory models and of natural joints at two sites in 

Sweden. The concrete blocks, each of which 

contained from 2 to 20 joints, were tested by using 

a pulse generator having a swinging metal head as 

a sound source. According to the authors, "the 

calculated depth of jointing is in good agreement'' 

with actual joint depth. 

Field tests were performed by using an 

explosive-filled, hollow-cylinder energy source. 

Experimentally determined depths of joints within 

a granitic gneiss were less than the actual depths 

measured directly on the face of a pit within the 

gneiss. This effect was attributed to deformation of 
the joints by a horizontal stress field within the 

rock body. At the other field site-an underground 

magnetite mine-the theoretically determined 

joint depth averaged 0.5 m, which is within the 

0.3- to 0.8-m depth range where the majority of 

joints were actually found. 

Taylor, R W., 1982, Evaluation of geophysical surface 

methods for measuring hydrological variables in 

fractured rock units: U.S. Bureau of Mines 

Research Contract Report, contract H0318044, 

147 p. 

Fractured bedrock was examined at two sites 

in southeastern Wisconsin by using the azimuthal 

resistivity technique, together with seismicvelocity and attenuation measurements. The sites 

are underlain by a Silurian dolomite, which 

unconformably overlies an Ordovician sandstone. 

At one of the sites, an oolitic iron formation is 

present between the shale and the dolomite. A thin 

(0- to 5-ft thick) layer of till overlies the bedrock. 

These sites were studied also by Leonard-Mayer 

(1984a, b) and by Taylor (1984). 

The azimuthal resistivity surveys were performed by using Wenner and Lee arrays rotated 

about a fixed point. Apparent resistivity readings 

were taken at 10° intervals, and constant a spacings were maintained. The results were plotted as 

apparent resistivity ellipses. The major axes of the 

ellipses correspond with the direction of primary 

joint strike within approximately so, whereas the 

secondary joint set had no effect on the resistivity 

ellipse. 

Vertical movement of rainwater through the 

ground was detected by continuously monitoring a 

depth-sounding array. This apparatus incorporated a microcomputer and permanently emplaced 

electrodes. 

Seismic data were collected by using a 6-

channel seismograph and a sledgehammer sound 

source. P-wave first-arrival times and attenuation 

of P-wave first breaks and Rayleigh wave peaks 

were recorded as a function of azimuth. These 

measurements did not provide any useful information. 

The authors concluded that, by analyzing the 

electrical resistivity measurements, they were able 

to determine the primary strike of joints without 

further field work. The seismic measurements 

were judged to be of no value for this application. 

Taylor, R W., 1984, The determination of joint orientation and porosity from azimuthal resistivity measurements, in Nielsen, D.M., and Curl, M., eds., 

National Water Well Association/U.S. Environmental Protection Agency Conference on Surface 

and Borehole Geophysical Methods in Groundwater Investigations, San Antonio, Texas, 1984, Proceedings: Worthington, Ohio, National Water 

Well Association, p. 37-49. 

At two sites in Wisconsin, azimuthal resistivity surveys were used to determine strike and 

porosity of joints in a Silurian dolomite over lain by 

approximately 2m of till. These sites were examined also by Taylor (1982) and by Leonard-Mayer 

(1984a, b). The major axis of the resistivity ellipse 

defined in this survey corresponded with the primary strike direction of the joints, as previously 

determined by other means. Joint porosities determined from the resistivity survey were within 

approximately 2 percent of the porosities as determined by gravity and seismic methods. The author 

concluded that the azimuthal resistivity method can 

be used successfully to determine the geometry 

and porosity of joint patterns within bedrock. 

Technos, Inc., 1985, Hydrogeologic investigation of 

the Ironwood Landfill, Spring Valley, Minnesota: 

10 

Miami, Fla., Technos, Inc., 88 p. 

EM (electromagnetic conductivity) and 

resistivity-sounding surveys were used to evaluate 

fluid flow through a fractured rock aquifer at a 

hazardous-waste landfill near Spring Valley, 

Minn. This landfill was the site of similar work by 

Leonard-Mayer (1984a, b). The study area is 

underlain by Ordovician and Devonian shales and 

carbonates that are covered by discontinuous 

unconsolidated sediments up to 15 ft in thickness. 

The upper 1 to 10 ft of bedrock is weathered to 

sand- and silt-sized particles, whereas the deeper 

units are cut by fractures and solution features. In 

addition, extensive karst topography was observed 

near the site. 

The EM surveys traversed a total of 15 

linear miles and penetrated to depths of 20, 50, 

and 100ft. Nine resistivity soundings were made 

by using a Wenner array. Fractures were recognized as linear areas of increased conductivity 

(decreased resistivity) in both the EM and 

resistivity-sounding surveys. Water within the 

fractures caused the increased conductivity. This 

effect was further enhanced by the presence of 

landfill leachate within the water. Many of the 

linear anomalies observed in this survey were 

correlated with previously observed photolinea-
ments or with other features that indicate fracture 

zones. 

Ulriksen, C.P.F., 1982, Application of impulse radar 

to civil engineering: Hudson, N.H., Geophysical 

Survey Systems, Inc., 179 p. 

Impulse radar has been used by engineers 

and geophysicists for applications as widely varied 

as detecting salt damage in highway concrete and 

detecting fractures in bedrock. This type of radar 

transmits energy over a wide spectrum of frequencies rather than over a single frequency. Subsurface targets are located by their contrasting electrical properties. Highly resistive materials, such 

as most types of rock, are relatively transparent to 

radar waves and allow deep penetration. Radar 

waves will not penetrate highly conductive materials such as clay, shale, metallic ores, or rock 

having conductive ground water. 

This technique was successfully applied to 

detect fractures in a granodiorite in Sweden. Two 

fracture zones were detected at a depth of 10 m, 

and their locations were confirmed by borehole 

observations. Impulse radar has been used also to 

detect a horizontal bedding plane approximately 3 

m beneath the surface at a quarry in Sweden. The 

lithology of the rock is not specified. The radar 

record from this site is strikingly similar to a 

photograph of the quarry face. 

Wire, J.C., Hofer, J.K., and Moser, D.J., 1984, 

Ground magnetometer and gamma ray spectrometer surveys for groundwater investigations in bedrock, in Nielsen, D.M., and Curl, M., eds., 

National Water Well Association/U.S. Environmental Protection Agency Conference on Surface 

and Borehole Geophysical Methods in Groundwater Investigations, San Antonio, Texas, 1984, Proceedings: National Water Well Association, p. 

288-315. 

This paper describes how ground magnetometer and gamma-ray spectrometer surveys 

were used to locate faults, contacts, weathering 

zones, and fracture zones within bedrock at several sites in California. Water migrating through 

bedrock fractures oxidizes magnetic minerals and 

decomposes rock-forming minerals. The effects 

of these processes are revealed in magnetometer 

surveys as magnetic lows. The alteration zone also 

becomes depleted in some radioactive elements; 

this depletion causes anomalous total gamma-ray 

counts. Surveys of this type are reportedly most 

useful in felsic igneous and metamorphic rock 

and may be useful also in fractured sandstone. 

Results in fractured shale, or in more complex 

sedimentary environments such as dipping beds, 

are "more difficult. .. to evaluate." 

Surveys performed at a site in the Sierra 

Nevada batholith revealed magnetic and gammaray lows that suggest the presence of a fracture 

zone. This information was supplemented by 

observations at outcrops and by geological maps. 

A VLF survey was used with a resistivity sounding 

survey to locate a productive well within the fracture zone. 

Wright, C., Lam, C. P., and Johnston, M., 1980, 

Seismic wave velocities in a rock body at Chalk 

River, Ontario, and their relationship to fractures 

[abs.]: Eos, Transactions of the American 

Geophysical Union, v. 61, no. 17, p. 361. 

11 

This survey detected fractures within crystalline rock at Chalk River, Ontario, by measuring 

seismic P- and S-wave velocities within the rock. 

Sound sources included a mechanical hammer 

and a shear wave gun. Surface and borehole 

geophones were used for recording. The surveys 

consisted of three shallow reflection lines up to 1. 3 

km long. Different seismic velocities noted were 

attributed to wave propagation through fractured 

gneiss and quartz monzonite and thin sheets of 

gabbro. 

FOREIGN LANGUAGE REFERENCES 

The follo.ving papers were published in a foreign 

language, and fully translated versions of them were 

not available. Foreign language versions are available 

through the inter library loan system. 

Aleksandrov, B. L., 1973, Eksperimental' nyye issledovaniya vliyaniya fil' trtsii rastvora v treschinakh 

na soprotivleniye karbonatnoy parody [Experimental studies of the influence of movement of 

solutions through fractures on [electrical] resistivity of carbonate rocks]: Vyssdh. Uchebn. Zaved., 

Izv., Neft' Gaz N. 6, p. 21-25. [In Russian.] 

Bro, Maurice, and Hubert, Christian, 1980, Recherche des aqiferes de fracture dans les series 

schistoso-greseuses au Maili a 1' aide des techniques geophysiques [Exploration for aquifers in 

the fractured schistose sandstone formations of 
Mali using geophysical techniques]: Int. Geol. 

Cong. Abstr. -Congr. Geol. Int., Resumes 26, v. 

3, p. 1092. [In French.] 

Faillat, Jean-Pierre, Leblond, Pierre, and Prevot, 

Jean, 1980, &sai d'adaptation de la methode des 

resistivities aux recherches d' eau dans les terrains 

cristallins fissures et fortement alteres de Cote 

d' Ivoire [Application of the resistivity method to 

water exploration in the highly altered fissured 

crystalline terranes of the Ivory Coast]: Int. Geol. 

Cong. Abstr. -Congr. Geol. Int., Resumes 26, v. 

3, p. 1109. [In French.] 

Gershanovich, I.M., 1975, Razvedka mestorozhdeniy 

podzemnykh vod v tresch inovatykh porodakh 

geofizicheskiimi metod ami [Geophysical surveys 

of ground water in fractured rocks]: U.S. S. R, 

Izd. Nedra. [In Russian.] 

Lachaud, J.C., 1983, Role de la geophysique par 

methode electrique appliquee ala prospection des 

eaux souterraines en milieu fissure [Role of 

geophysics (electrical method) applied to prospection of ground water in fractured media]: Eau 

l'Industrie, Les Nuisances, v. 71, p. 37-40. [In 

French.] 

Lokin, Petar, and Jevremovic, Dragutin, 1977, 

Metodologija ispitivanja ispucalosti neotkrivenih 

stenkskih masa [Methods for the investigation of 

fractures in covered rock masses]: Zb. Rad., 

Rud-Geol. Fak., Univ. Beogradu 20, p. 311-324. 

[In Russian, with English summary.] 

Stephansson, Ove, Lande, G., and Bodare, A, 1978, 

Seismik for ytuppsprucket berg [A seismic study 

of shallow jointed rocks]: fuerdrag och diskussioner vid Bergmekaniskt diskussionsmote: Stiftelsen Bergteeknisk Forskning-BePo, p. 217-234. 

[In Swedish, with English Summary.] 

Vaubourg, P., 1979, Developpement des recherches 

d' eau souterraine en milieu fissure; resultats obtenus en Bretagne (France) [Development of methods of investigating ground water in fractured 

rocks; results in Brittany, France] [and] Methodes 

d' evaluation des ressources en eau souterraine 

[Methods for evaluation of ground-water 

resources]: Int. Assoc. Hydrogeol. Mem., v. 15, 

no. 1, p. 188-191. [In French with Russian 

Summary.] 

The following references could not be obtained 

through the interlibrary loan system. 

Bjelm, L., rollin, S., and Svensson, C., 1982, Geo 

radar som undersokningsmetod [ Georadarlike 

investigation method] BFR project no. 800141-9, 

Coden: LUTVDG/(TVTG-3002)/1-71!1982. 

[In Swedish.] 

Brion, M., and Lachaud, J. C., 1979, Experimentations de methodes a Ia recherche d' eau dans les 

roches cristallines fracturees [Experimental application of geophysical methods to water exploration 

in fractured crystalline rocks]: Interafrican 

Comm. Hydraul. Stud., Liaison Bulletin, v. 

37-38, p. 14-23. [In French.] 

Glushko, V.T., Vinogradov, V.V., and Yalans'kiy, 

AO., 1973, Doslidzhennya masivu girs'kikh 

porid u zoni nepruzhnikh deformatsiy na osnovi 

ul' trazvukovogo metodu [Ultrasonic surveys of 

the brittle deformation zone of a rock massif]: 

Akad. Nauk Ukr. RSR, Dopov., Ser. B, no. 7, p. 

613-616. [In Ukrainian, with English and Russian summary.] 

Ikeda, K., 1980, Property and seismic wave velocity of 

fractured zones: Buts uri-Tanko, v. 33, no. 3, p. 

34-41. [In Japanese, with English summary.] 

12 

SUMMARY 

During the past decade, the number of published 

reports on the application of surface geophysical techniques to detect fractures in rock has increased. This 

bibliography contains only 8 references published from 

1972 through 1978, but 10 are listed in 1984. No 

references before 1972 were located. Many of the early 

articles listed were published in foreign languages, 

notably Russian, whereas the majority of the more 

recent articles are in English. 

The most widely used techniques for fracture 

detection have been the various D. C. resistivity, 

seismic-reflection, and seismic-refraction methods. 

These methods have been used in a wide variety of 

geologic settings, in straight line and in rotating-array 

surveys. In the straight line surveys, measurements are 

made along a line having a constant azimuth. Fractures 

or fracture zones are detected as lateral anomalies in 

the geophysical property being measured. In rotatingarray surveys, the arrays are rotated about a fixed point, 

and geophysical measurements are made at fixed intervals of rotation. Fractures or fracture zones are detected 

as directional variations in the geophysical parameter 

being measured. The most common rotating-array 

method has been the azimuthal-resistivity survey. 

A number of other surface-geophysical techniques have been used to detect and characterize fractures, including magnetometer and gravity surveys, 

VLF surveys, ground-penetrating radar, gamma-ray 

spectrometry, and subsurface temperature measurements. None of these methods have been as widely 

applied as the various D. C. resistivity and seismic 

techniques. 
Although the use of surface geophysical methods 

to detect bedrock fractures has increased, most of the 

reported studies are experimental in nature. No one 

has reported widespread use of these methods in a 

routine production mode. Most of the surveys currently 

being performed are still designed to improve understanding of a particular method or to prove that the 

method works, rather than to acquire data to help solve 

a real problem in the field. 

REFERENCES CITED 

Aamodt, L, Albright, J., Potter, R, Aki, K., and Fehler, M., 

1977, Seismic methods for defining fractures of a hot dry rock 

geothermal system [ abs.]: Eos, Transactions of the American 

Geophysical Union, v. 58, no. 6, p. 1187. 

Bazinet, Robert, and Legault, Jean, 1985, Scalar audiomagnetotellurics: A tool in the evaluation of nuclear waste disposal 

sites: Society of Exploration Geophysicists Annual International Meeting, 55th, Washington, D. C., 1985, Expanded 

abstracts of the technical program with author's biographies, 

p. 149-150. 

Green, AG., and Mair, J.A, 1983, Subhorizontal fracture zones 

in a granitic pluton: Their detection and implications for 

radioactive waste disposal: Geophysics, v. 48, no. 11, p. 

1428-1449. 

Mair, J.A, and Green, AG., 1981, High resolution seismic 

reflection profiles reveal fractures within a homogeneous 

granite batholith: Nature, v. 294, p. 439-442. 

Paillet, F. L, 1985, Problems in fractured-reservoir evaluation and 

possible routes to their solution: The Log Analyst, v. 26, p. 

26-41. 

Soonawala, N.M., and Dence, M.R, 1981, Geophysics in the 

Canadian nuclear waste program-A case history: Society of 

Exploration Geophysicists Annual International Meeting, 

51st, Los Angeles, Calif., 1981, Proceedings: Tulsa, Clclahoma, Society of Exploration Geophysicists, p. 83-98. 

Stephansson, Ove, Lande, G., and Bodare, A, 1979, A seismic 

study of shallow jointed rocks: International Journal of Rock 

Mechanics and Mining Sciences & Geomechanics Abstracts, 

v. 16, p. 319-327. 

Wright, C., Lam, C.P., and Johnston, M., 1980, Seismic wave 

velocities in a rock body at Chalk River, Ontario, and their 

relationship to fractures [abs.]: Eos, Transactions of the 

American Geophysical Union, v. 61, no. 17, p. 361. 

GLOSSARY 

Acoustic coupling. The efficiency with which seismic energy is 

transmitted to a geophone. 

Analog. (1) A continuous physical variable, such as voltage 

produced by a geophone, which bears a direct relation to 

another variable, such as motion of the Earth produced by a 

seismic wave, so that one is proportional to the other. (2) 

Continuous, as opposed to discrete or digital. 

Array. (1) Electrical. The arrangement of electrodes used in 

electrical surveys. Also called configuration. There are many 

different arrays, including Wenner, Lee, Schlumberger, gradient, dipole-dipole, and so on. (2) Electromagnetic. An 

arrangement of antennas. (3) Seismic. The arrangement or 

pattern of a group of geophones or source points. 

Aspect ratio. The ratio of a fracture's length to its width. 

Apparent formation factor. The ratio of the measured resistivity 

of a 100-percent saturated formation to the resistivity of the 

water with which the formation is saturated. 

Apparent resistivity. The resistivity of homogeneous isotropic 

ground that would give the same voltage-current relation as 

that measured in the field. 

Attenuation. A reduction in amplitude or energy of a seismic or 

electromagnetic wave caused by the physical characteristics of 

the transmitting media or system. 

Audiomagnetotelluric method (AMT). A method in which subsurface resistivity is determined by simultaneously measuring 

the orthogonal components of naturally occurring horizontal 

electric and magnetic fields as a function of frequency. This 

method uses energy in the audio (10 to 10,000 Hz) range. The 

energy is produced as a result of lightning discharges. 

Azimuthal resistivity array. A dipole-dipole array that is rotated 

about the survey point to map variation with direction of 

apparent resistivity. 

Borehole televiewer. A well log in which a pulsed, narrow 

acoustic (sonar) beam scans the borehole wall in a tight helix 

as the tool moves upward. The amplitude of the reflected wave 

is displayed on a cathode ray tube and reveals fractures and 

other discontinuities in the side of the borehole. 

Bulk modulus (K). The ratio of stress to strain in a system under 

simple hydrostatic pressure. 

Conductance. For direct current, the reciprocal of resistance, for 

alternating current, the resistance divided by the impedance 

squared. Measured in siemens (S), or mhos, which are the 

inverse of ohms. 

Conductivity (specific conductance). The ability of a material to 

conduct electrical current, measured in S/m or mhos/m. In an 

isotropic material, equals the inverse of resistivity, in ohm/m. 

Critical angle. The angle of incidence at which the refracted ray 

grazes the surface of contact between two media of differing 

seismic velocities. (It is significant only when V2 is greater 

than vl.) 

Cultural interference. Interference with geophysical measurements due to manmade sources, such as powerlines, buried 

pipelines, fences, and so on. 

Deconvolution. A process designed to restore a waveshape to the 

form it had before it underwent linear filtering. 

Depth sounding. Measurements of a seismic or electromagnetic 

property as a function of depth. 

Digital. The representation of information as a series of discrete 

numbers (rather than in analog form, where information is 

represented as a continuous flow of the quantity constituting 

the signal). 

Fan shooting. Aseismic-refraction technique in which geophones 

are located along the arc of a circle. 

Forward modeling. Prediction of the geophysical measurements 

that would be observed by a given technique by using a 

hypothetical Earth model. 

Fracture. A break in rock along which no appreciable movement 

has occurred. 

13 

Gamma-ray spectrometer. A device that measures gamma rays 

produced by radioactive elements. By measuring the energy 

levels of gamma rays, the device can determine which element 

is the source of the rays. 

Geophone. A sensitive device used to transform seismic energy 

into electrical voltage for input to a seismograph. 

Gravity survey. A survey that measures the strength of the 

gravitational field at various points in an area. 

Ground-penetrating radar. A system that transmits pulses of 

radar energy into the ground to map geologic structures. 

Huygen's principle. A concept stating that every point on an 
advancing wavefront can be regarded as the source of a 

secondary wave. 

Inverse modeling. A technique that determines an Earth model 

that can produce geophysical measurements observed in the 

field. 

Joint. A fracture in rock, generally more or less vertical or 

transverse to bedding, along which no appreciable movement 

has occurred. 

Magnetometer. An instrument to measure the strength of a 

magnetic field. It measures the vertical or horizontal component of a field or the total field. 

Photolineament. A linear feature visible on aerial or satellite 

photographs that differs significantly from the patterns in the 

surrounding area. It is presumed to reflect a subsurface 

feature. 

P wave (compressional wave). An elastic body wave in which 

particle motion is in the direction of propagation. 

Rayleigh wave. (1) A type of seismic wave propagated along the 

free surface of a semi-infinite medium. Particle motion near 

the surface is elliptical and retrograde in the vertical plane 

containing the direction of propagation. (2) A wave similar to 

(1), but the medium is not semi-infinite. (3) A tube, or surface 

wave, that propagates within a borehole. 

Reflector. (1) Seismic. A contrast in acoustical impedance 

between two subsurface units that causes acoustic energy to be 

reflected. (2) Electromagnetic. A contrast in electrical properties that causes electromagnetic waves to be reflected. 

Refractor. A layer having higher seismic velocity than that of 

overlying layers through which a seismic wave travels and is 

refracted. 

Residual resistivity. The difference between the locally observed 

resistivity and the regional resistivity. 

Resistance. Opposition to the flow of direct current, measured in 

ohms. The inverse of conductance. 

. ' 

Resistivity (specific resistance). The property of a material that 

resists the flow of electrical current, measured in ohm-meters. 

The inverse of conductivity. 

Scalar. A number that is not associated with a specific direction. 

Seismic-reflection method. A seismic method in which measurements are made of the arrival times of seismic waves that have 

been reflected from interfaces where changes in acoustical 

impedance occur. 

Seismic-refraction method. A seismic method that incorporates 

seismic waves that enter a high-velocity medium near the 

critical angle and travel through that medium nearly parallel 

to its surface. The measured arrival times of the refracted 

waves are an indicator of the depth to _each refractor. 

Seismic velocity. The propagation rate of a seismic wave, without reference to direction. 

Streaming potential. Voltage resulting from flow through the 

ground of fluid that contains ions. 

Synthetic seismogram. An artificial seismic record created by 

assuming that a particular waveform travels through a hypothetical model of the Earth. 

Tensor. A set of quantities that relates different vector fields 

within a vector. Usually expressed as a matrix. 

Total-field ground magnetometersurvey. Aground-based magnetometer survey in which the total magnetic field is measured 

rather than its horizontal or vertical components. 

Traveltime diagram (time-distance diagram). A plot of the 

arrival time of refraction seismic waves as a function of the 

distance from the shotpoint to the geophone. 

Tri-potential resistivity. A resistivity survey method in which 

three different electrode arrays are used together. 

Vector. A quantity having both a magnitude and a direction. 

Vertical profile. Measurements of the response of a geophone at 

various depths in a borehole to shots on the surface . 

nUS. GOVERNMENT PRINTING OFF •.. !- 1987 - 181-405 - 2:: '4oo· 



Lewis and Haeni-SURFACE GEOPHYSICAL TECHNIQUES TO DETECT BEDROCK FRACTURES -BIBLIOGRAPHY-U.S. G