ALBERT

Notes: The purpose of the automatic gain control in seismic amplifiers is to balance the slow decrease of the signal in such a manner that its energy does not exceed the capacity of the recording system. At the same time the interesting seismic content of the signal has to be preserved as undistortedly as possible. At first, the technical data of AGC circuits are calculated. The characteristic curves of circuits with one, two, and three time constants are computed. In circuits with two and more time constants an oscillating of the AGC is possible. In order to guarantee aperiodic operation, the ratio of the time constants must not fall below a certain value. As long as these technical conditions are complied with, the free choice of the largest time constant remains open and can be accommodated to the geophysical conditions.From the endeavour to balance the slow decrease of the signal as well as possible, an upper limit for the choice of the time constants can be derived. A lower limit is obtained from the condition that the seismic content of the signal has to be preserved. The determinant time constant should lie between the two limits and differ from them as much as possible.Finally, the problem of the amplifier “squeezed” by energy pulses is touched.

Notes: Book Review in This Article:P. F. Shokin, Gravimetry (Apparatus and Methods for Measuring Gravity)

Notes: The paper deals with quantitative seismic measurements near underwater explosions. The blastings were carried out in an artificial small pond, the records were taken in adits, situated vertically below the charge. The range of charges extended from one detonator to 200 g of Ammon-Gelit explosive.Conventional seismic scaling by comparing amplitude and size of charge does not yield a simple power law, the exponent being larger for smaller charges and vice versa. This result is due to the different frequency-spectra of the seismic pulses, as shown by harmonic analysis. In contrast to this, the seismic energy as calculated from the records is directly proportional to the size of charge over the whole range.During the Lago Lagorai experiments in 1962 some quantitative seismic measurements near the shot point were also carried out. The relevant results are compared with the preceding ones and some differences are discussed.Some conclusions can be drawn:〈list xml:id="l1" style="custom"〉1The normal methodes, investigating the amplitude only, gives in many cases no clear description; this is especially true for nearby measurements with widely varying frequencies. Therefore it is suggested to extend conventional seismic scaling by including information on the frequency-spectrum and the kinetic energy of the seismic signal.2In order to get clear experimental data for theoretical investigations, it is necessary to extend the recording over a half-space, i.e. in adits or boreholes.3Influences of shape and size of the lake, in which the shots are fired, should be taken into account, too.

Notes: The magnitude of the streaming potential due to the passage of a liquid through a porous medium is examined, under conditions similar to those found in an aquifer under the action of a pumping well. Three models simulate flow in channels, conduits, and unconfined aquifers for several grain sizes of sands and for several resistivities of fluids. The ratio of the streaming potential to the pressure difference is constant for a selected sand and fluid, decreases as grain size increases, is essentially independent of the geometry of the flow, increases slightly as the permeability decreases, and decreases as the salt concentration increases. Extremely low streaming potentials can be expected near a pumping well.

Notes: Book received in this Articles:P. E. Potter and F. J. Pettijohn, Paleoccurrents and Basin Analysis

Notes: Book Review in This Article:Robert L. Miller and James Steven KahnYe. P. Fedorov, Nutation and Forced Motion of the Earth's Pole. Translated from the Russian by Bertha Swirles Jeffreys, Foreword by Sir Harold Jeffreys.

Notes: Case history of the use of fan filtering for improving reflection continuity without destroying their character. The field technique is described: wide-band, large dynamical range recording with a programmed gain control and a very slow A.G.C., small distance between trace centers, high cutoff wave-number.Although the total amount of mixing due to fan filtering is rather high, a broad spectrum was obtained and inverse convolution filtering was used to improve trace resolution.

Notes: Graticules are known for the calculation of the magnetic field of homogeneously magnetized “two-dimensional” structures. For bodies whose lateral dimensions are comparable with the dimensions of the cross section and/or the distance between the point of observation and the structure, these graticules allow an approximative computation of the field in the plane of symmetry only. The degree of approximation can be improved by means of end corrections, but the amount of work involved increases rapidly. Moreover, even with end corrections the applicability of the graticules is still restricted to cases of rather simple geometry.In this paper, a set of graticules is proposed which already incorporates all end corrections. The set consists of three graticules, and it can be shown that at any point of observation lying outside the body each graticule needs be applied once only in order to calculate any component of the magnetic field produced by a homogeneously magnetized cylinder of arbitrary cross section, finite lateral extension and arbitrary spatial orientation.Curves and tables have been prepared, which allow the construction of the graticules under consideration. The application is illustrated by a hypothetical example. Possibilities for further improvements of the method are discussed.

Notes: By this method an approximation of gravity-anomaly of an inhomogeneous mass with any form is calculated. The mass is inbedded in a homogeneous medium. The density of the medium differs from the density-distribution of the mass.

Notes: Book Review in this Article:H. Israel and A. Krebs, Nuclear Radiation in GeophysicsB. A. Tkhostov, Initial Rock Pressures in Oil and Gas DepositsJohn S. Steinhart and Robert P. Meyer, Explosion Studies of Continental Structure

Notes: Pour caractériser les anomalies de la carte initiate et de la carte transformeé, on définit des indices de netteté désingés respectivement par I0 et I et on étudie le rapport I/I0 pour diverses formules appliquées à trois anomalies typiques (sphère, anticlinal, faille). Les courbes obtenues permettent d'introduire, par analogie avec les circuits électriques, des notions telles que profondeur de coupure et pente.

Notes: In the case where a medium of velocity α1 is underlain by a medium of higher velocity α2, no propagation of compressional elastic wave energy into the lower medium takes place at angles of incidence exceeding a certain critical value. This so-called critical angle –which is a measure of the actual velocity-contrast –is furthermore marked by a sharp increase in the amount of reflected compressional energy. An investigation has been made to find out whether this critical-angle effect might be usable as a velocity-contrast indicator in seismic exploration.Model experiments confirmed the expectation that this effect should be manifest at the surface under ideal conditions.Two small-scale field set-ups showed that the effect is actually measurable in the field (in one case after applying corrections for planting variations).Finally a seismic line along the shore of the North Sea provided the data for contrast analysis over a considerable distance along the base of the Tertiary. Comparison of the measured changes in contrast and subcrop velocities obtained at those locations where subsurface data from independent sources were available, showed good agreement.It is concluded that critical-angle shooting may be used to indicate subcrop changes along a reflector, or even to obtain the same sub-stratum velocity as is sought in conventional refraction work, at considerably shorter operating distances.

Notes: Nach einer kurzen Einführung über das Prinzip der Vibratortechnik werden Ergebnisse vibratorseismischer Arbeiten auf Platten (Eis, Betonplatten, Straßendecken) mitgeteilt. Der Auswertung wurden Biegewellen zugrunde gelegt und die ermittelten experimentellen Ergebnisse mit theoretischen Dispersionskurven verglichen.

Notes: Using optimum filter theory as a starting point, we describe a method for the design of practical multi-trace seismic data processing systems. We assume the inputs to be the superposition of signal, coherent noise, and incoherent noise. The signal and coherent noise moveouts are described statistically by their probability densities. Our approach is to split the system into two stages. The first stage achieves optimum noise suppression but distorts the signal. The signal distortion is reduced in the second stage by an optimum finite memory inverse filter.The system that is obtained using our method of design depends upon the form of the probability density functions. We show two examples, ghost suppression and velocity filtering. In ghost suppression we choose a model with moveouts known exactly, which corresponds to delta functions for the probability densities. In velocity filtering the signal and coherent noise moveouts are equally probable within non-overlapping ranges.The resulting system in each case is both simple and effective. In ghost suppression a simple shift and subtract cancels the coherent noise. The signal distortion is reduced by an inverse filter. The velocity filter system consists of differentiated moving averages applied to each trace, followed by a 90° phase shift and a low pass filter.

Notes: A graphical method of interpreting refraction data is presented based upon wave front construction in which different overburden velocity distributions can be used. The wave fronts are constructed with the aid of an Isochron Chart. By using two or more Isochron Charts, the effect of velocity variations above the refractor of interest can be allowed for.

Notes: This study is an attempt to find a phenomenological model which will behave in a manner similar to that of common earth materials in regard to the dependence of attenuation and phase velocity on frequency.An analysis of two commonly employed rheological models, Maxwell's and Kelvin-Voigt's and their variants, is presented indicating that these models are too simple to conform phenomenologically to the behavior of rocks. It is shown that a linear combination of the Maxwell and Kelvin-Voigt models, known as the standard linear solid, comes closer to giving an adequate description of the behavior of some earth materials, than either one of the two models.A method of determining the viscoelastic constants of a solid is presented provided that its attenuation and dispersion curves are known. The viscoelastic constants (relaxation times and/or viscosity coefficients) of the solid are determined by superimposing the experimental curves on master curves, and reading the constants off the theoretical curves.An analysis of published experimental data is presented, indicating that the present model is capable of accounting for at least some attenuation and dispersion phenomena.

Notes: Normally only operational checks are made on geophones in the field because of the lack of suitable test equipment. The test method described here was developed to enable accurate (better than 1 %) measurements to be made, in the field, of all geophones in common use which have natural frequencies of i c/s or greater.The portable field instrument is simple to operate and can be used to test refraction and reflection geophones, either singly or in series strings.

Notes: An analytical expression for the time-distance curve of seismic waves travelling in a medium consisting of intrinsically anisotropic layers with arbitrarily dipping plane interfaces can be given in terms of the “co-ordinates” of the interfaces (length h of the perpendicular from the shotpoint to the interface, strike ν and dip α of the interface) if for each layer the velocity is given as a function of the orientation of the wave normal. The interpretation of the time-distance curve is understood as the inverse process, namely finding an expression for the co-ordinates in terms of some characteristics of the time-distance curve, e.g. intercept times and apparent velocities. In addition, it is useful to know where the “limiting ray”, which is the ray connecting shotpoint and last geophone, enters and leaves a specific layer, for it is only on the medium between these two points that information can be obtained by interpretation. As ray and wave normal do not generally coincide in anisotropic media, the location of these points cannot be calculated from the co-ordinates and the direction of the wave normal without recourse to the functional dependence between the directions of ray and wave normal.An analytical solution of this problem would involve the solution of a number of equations, implicitly containing several parameters. Successive approximation would be rather cumbersome. Instead, a graphical method is proposed which yields all pertinent information without calculation.

Notes: This article deals with the effect that the Königsberger ratio, the ratio of remanent to induced magnetization, has in modifying the dipping-dyke equation. Many reversed dykes are found on aeromagnetic maps and their presence indicates that remanent magnetism must often play a significant part in the magnetic expression of normally-polarized dykes. The methods for the measurement of remanent magnetization and susceptibility (k) are outlined, and the relationship between k and volume % magnetite (V) is discussed. It is proposed that a good approximation is k= 0.15 (x−1 - x), where x=1-V/100. The general equation for the dipping dyke, which includes the contribution of remanent magnetization, is given. A method of obtaining k from the magnetic map is also derived.

Notes: This paper deals with transient response of resistive formations to pulse sources. Computation of solutions of equations such as:〈displayedItem type="mathematics" xml:id="m1"〉1〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR325:GPR_325_m1"/〉is linked to computation of solutions of equations such as:〈displayedItem type="mathematics" xml:id="m2"〉2〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR325:GPR_325_m2"/〉It can be used in the case where several media exist, the conductivities of which are σ1 σ2.The method consists in establishing a correspondence between the case to be dealt with and a fictitious region of space with the same interfaces, in which the propagation of a disturbance obeys Equation (2).Velocities C1 C2. are related to conductivities by the condition〈displayedItem type="mathematics" xml:id="m3"〉3〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR325:GPR_325_m3"/〉At the interfaces, the distribution of incident energy between transmitted and reflected energy is related to the ratio of characteristic impedances, i.e.〈displayedItem type="mathematics" xml:id="mu1" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR325:GPR_325_mu1"/〉in the real case (ω is the angular frequency) and C1/C2 in the fictitious case.These ratios are the same because of Equation (3).Time variation g(θ) of solution of (1) in a given point is computed from time variation of solution of (2) at the same point by means of the transformation〈displayedItem type="mathematics" xml:id="m4"〉4〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR325:GPR_325_m4"/〉(in which τ is the actual time and T the time unit).Equation (4) originates from a formula of symbolic calculus, that allows the Laplace transform of F(Vp) to be calculated from the known Laplace transform of F(p). This correspondence is the one that allows passage from 〈inlineGraphic alt="inline image" href="urn:x-wiley:00168025:GPR325:GPR_325_mu2" location="equation/GPR_325_mu2.gif"/〉 in (1) to 〈inlineGraphic alt="inline image" href="urn:x-wiley:00168025:GPR325:GPR_325_mu3" location="equation/GPR_325_mu3.gif"/〉 in (2)Equation (4) becomes considerably simpler when the response 〈inlineGraphic alt="inline image" href="urn:x-wiley:00168025:GPR325:GPR_325_mu4" location="equation/GPR_325_mu4.gif"/〉 to the unit impulse consists (as happens most often) of the sum of a finite or infinite number of pulses 〈inlineGraphic alt="inline image" href="urn:x-wiley:00168025:GPR325:GPR_325_mu5" location="equation/GPR_325_mu5.gif"/〉 The results is then a sum of functions such as:〈displayedItem type="mathematics" xml:id="mu6" numbered="no"〉〈mediaResource alt="image" href="urn:x-wiley:00168025:GPR325:GPR_325_mu6"/〉Hence, this procedure appears as an extension to systems that obey Equation (1) of the image theory very often used when Equation (2) is applied.

Notes: The exact responses of plane interfaces to incident spherical compressional waves are calculated by an electronic computer. The reflected part of the response is shown for various positions of the ‘shot’ and of the ‘receiver’ as well as for various velocity contrasts. This makes it possible to study some features of the reflection process, especially the behaviour beyond the critical angle.

Notes: The problem of three-dimensional migration is solved for arbitrary, three-dimensional, continuously differentiable velocity functions v=v (x4) by means of series.The derived formulae are applied to numerical examples.The possibility of approximating real, discontinuous velocity distributions by continuous functions is mentioned and illustrated by an example.The application of electronic computers, which is necessary due to the complexity of the formulas, is discussed.

Notes: Increased activity in the fields of ground-water geology and hydrology has focused attention on the academic preparations required of a geologist or engineer planning to enter the field of ground water. In an effort to improve understanding of the educational facilities available in the United States and Canada, the Research Committee of the Technical Division of the National Water Well Association is periodically inquiring into the status of these facilities.To arrive at a better understanding of the formal course work in ground water, a seven-item questionnaire was circulated to appropriate educational institutions in May 1960. A report, “Educational and Academic Research Facilities in Ground-Water Geology and Hydrology in the United States and Canada”, was published in May 1961 summarizing the information obtained from returned questionnaires. A similar survey was made in May 1963 to obtain data on advancements in educational facilities in ground water since 1960.This report, a contribution of the Technical Division of NWWA, is based on questionnaires completed in 1963 and provides statistical data on university and college facilities in the field of ground water. Detailed information is presented on 1) course work, 2) textbooks, 3) degrees granted, 4) descriptions of departments offering course work, 5) course instructors and 6) student training and employment. Recent advancements in educational facilities are summarized. It is hoped that the statistical and descriptive information embodied in this report will provide a suitable background for those who wish to assess the adequacy of available educational facilities in ground-water geology and hydrology.

Notes: This paper describes the new percussion-reverse circulation system, designed and developed in Italy for water-well drilling. In a special reverse circulation rig, the percussion bit, consisting of a tube with external welded blades, slides up and down on the outside of the hollow drill pipes, while the hollow drill pipes remain still. The field of application of the reverse circulation method is thus enormously enlarged; either hard, cemented formations or soft, unconsolidated deposits, as well as big boulders of any size are bored much faster and more efficiently than with any other method of drilling, provided that a sufficient source of water is available.

Notes: My subject does not deal directly with either wells or ground water - it does report to you the present (October, 1963) status of construction of one of the world's greatest projects in water resource development. What is the California State Water Project? What areas will it serve? What progress is being made? The answers are the story told in this paper.The magnitude of the project is measured in terms of quantity of water, money and time. The amount of water is four million acre-feet, estimated to meet the needs of the deficient areas it will serve until at least 1990. The cost is $1,750,000,000. The time is nine years from now to begin the delivery of water to the southernmost communities on the State's system.

Notes: Predictions of where and how a fluid waste may travel from disposal site to the water table require detailed information on the physical characteristics, location, and extent of all pervious and impervious materials in the unsaturated zone. Principles concerning the flow system in the unsaturated zone indicate the importance of choice of disposal technique in predicting the time required for the fluid waste to traverse the distance to the water table. With appropriate data on the location, extent, and physical properties of water-bearing materials and on the boundaries of the saturated zone flow system, it is possible to analyze the relative merits of a variety of waste disposal techniques and to describe the probable consequences of each. Environments of consolidated rocks, such as granites, sandstones, and limestones, pose problems in addition to those related to unconsolidated or granular porous media in defining the fluid-flow regimes that involve joint patterns, fracture patterns, solutional openings, and the rock structure.The consequences of ground-water contamination can be just as damaging to water users as the pollution of surface streams. In fact it can be argued that the consequences are far more damaging because they persist over much longer periods of time after the contaminating source has been eliminated. It would appear prudent, therefore, to guard against contamination of the ground-water resource in the first instance, rather than to engage in long expensive rehabilitation measures after the damage has been done.In 1960 Graham Walton presented data concerning contamination, by sewage or other man-made wastes, of surface and underground waters. The circumstances attending the reported incidents of contamination, especially those involving ground-water supplies, have aided materially in the choice of a few principles and ideas that will identify the role of some significant hydrologic factors in the underground movement of fluid wastes.Walton's discussion of ground-water contamination refers often to physical settings into which fluid wastes are discharged at or near the land surface into cesspools, tile-drain fields, and holding ponds. Furthermore, most reported instances of ground-water contamination have taken place in relatively humid

Notes: Future water-level declines in deep sandstone wells penetrating the Cambrian-Ordovician Aquifer, the most highly developed aquifer for large ground-water supplies in the Chicago region, are considered. The Cambrian-Ordovician Aquifer is encountered at an average depth of about 500 feet below the land surface at Chicago; it has an average thickness of 1000 feet and is composed chiefly of sandstones and dolomites. Recharge is received from overlying glacial deposits in areas averaging 47 miles west of Chicago and from leakage through a shale confining bed.Geohydrologic conditions are simulated by a model aquifer, i. e., a semi-infinite rectilinear strip of sandstones and dolomites 84 miles wide and 1000 feet thick. The model aquifer is bounded by a recharge boundary 47 miles west of Chicago and by two intersecting barrier boundaries 37 miles east and 60 miles south of Chicago, and is overlain by a confining bed consisting mostly of shale averaging 200 feet thick. The hydraulic properties of the model aquifer and its confining bed, the image-well theory, and appropriate ground-water formulas are used to construct a mathematical model which provides a means of evaluating the practical sustained yield of the aquifer and predicting future water-level declines. Records of past pumpage and water levels establish the validity of this mechanism as a model of the response of the aquifer to heavy pumping.Pumpage from deep sandstone wells concentrated in six pumping centers has increased from 200,000 gallons per day (gpd) in 1864 to 96.5 millions of gallons per day (mgd) in 1961. As a result of heavy pumping, water levels in deep sandstone wells declined more than 650 feet at Chicago between 1864 and 1961.The maximum amount of water that can be continually withdrawn from existing pumping centers without creating critical water levels or exceeding recharge is estimated to be about 46 mgd. Withdrawals from the Cambrian-Ordovician Aquifer have exceeded the practical sustained yield since 1959. It is estimated that about 65 mgd could be obtained by shifting one existing pumping center toward the west and by adding 2 new pumping centers north and northwest of Chicago.Unless lake water is made available to those areas with short supply a pumpage increase from 96.5 mgd in 1961 to 243 mgd in 2010 can be expected. Using this pumpage increase and taking into consideration dewatering of portions of upper units of the aquifer, declines in nonpumping water levels that may be expected between 1963 and 2010 at existing pumping centers were computed by using the mathematical model.Pumping water levels in most pumping centers will be at critical stages a few feet above the top of the lowermost and most productive unit of the aquifer by 2010.

Notes: Much underground gas storage depends on the presence of ground water for its effectiveness. Many of the techniques of the geohydrologist are useful in exploration, design, and development of underground storage fields for natural gas. Both local and regional geologic and hydrologic conditions are pertinent to gas storage effectiveness. Behavior of water in aquifers and their caprock zones can be used to predict behavior with gas. Leakage has been common in underground gas storage.Conflict between the public interest in gas storage and water resource development as both are expanded in the future is to be anticipated. There are many problems yet remaining in the development of underground gas storage to insure the complete effectiveness of design and operation.

Notes: Hydrogeologic studies in foothill watersheds have included diamond-core drilling, installation of observation wells, and pumping tests. Detailed study of recovered cores has provided reasonable estimates of porosity. Pumping tests of the two-inch diameter wells have given estimates of the transmissibilities ranging from 6 to 600 gallons per day per foot. Test data from several wells indicate that the hydraulics of water movement in jointed rock systems is not governed by the usual mathematical models.

Notes: It is of the utmost importance that ground-water users understand the basic concept that all the ground water within a single set of hydrologic and geologic boundaries is part of a single hydrologic system. It is therefore worthwhile for all ground-water users to understand the manner in which ground water moves through the pore spaces of saturated rock and to understand the various configurations of the water table brought about by the pumping of water table wells. The movement of ground water is illustrated in two hydraulic models which were constructed in order to bring ground-water flow into surroundings where it can be visually observed. The models consist of watertight plexi-glass cases containing a porous consolidated mixture of sand and epoxy resin, which simulates a true sandstone. The models are used to study cones of depression produced by pumping wells. Photographic histories of several ground-water flow conditions are illustrated.

Notes: The hydrology of ground-water recharge depends upon the physical and chemical characteristics of both soil and water. These characteristics must be measured and related to subsurface storage space and water movements to determine the feasibility of a site for recharge and to select appropriate methods and systems of recharge. Then water may be efficiently stored underground to be used independently or conjunctively with releases from surface storage reservoirs.

Notes: Flow-distribution curves, constructed from velocity graphs of current-meter traverses, can be used to locate water-bearing and nonwater-bearing zones in an aquifer or in separate aquifers in a well and to determine the quantity of water entering between various depths. Current-meter traverses in artesian wells in northeastern Florida show the applicability of flow-distribution curves.The velocities recorded in the uncased portion of a well by a deep-well current meter reflect either changes in the cross-sectional area of the bore at the different depths or movement of different quantities of water through the well at these depths. Reasonably accurate measurements of the flow at certain depths in the uncased portion of a well can be determined by constructing flow distribution curves. These curves are constructed by utilizing points of maximum velocity, which are assumed to be levels having the minimum diameter of the well.Artesian wells in northeast Florida are generally cased to the top of the Floridan aquifer through 500 to 600 feet of clay, marl, and dolomite of Miocene to Recent age. The wells are completed open hole in the Floridan aquifer to depths of from 650 to 1,400 feet. Current-meter traverses were run in four wells in the vicinity of Jacksonville.Flow-distribution curves constructed from the velocity graphs indicate three separate water-bearing zones occur in the aquifer. The first water-bearing zone lies from about 600 to 800 feet below the land surface; the second, from 900 to 1,200 feet; and the third lies below 1,280 feet. These water-bearing zones are separated by relatively impermeable non-water-bearing zones. Bar graphs constructed from the flow-distribution curves show that the first water-bearing zone yields from less than 10 to as much as 35 percent of the water; the second water-bearing zone yields more than 50 percent of the water; and the third water-bearing zone yields about 20 percent of the water with a penetration of only 50 to 70 feet. The flow-distribution curves from current-meter traverses made while there was no surface flow indicate internal leakage of less than 70 gallons per minute in wells 2 and 4 while the wells were not discharging at the surface. Leakage probably does not occur between these zones while the wells are discharging.

Notes: The writer reviews some of the best known features of mechanical dispersion and the influence of molecular diffusion on breakthrough curves obtained for saturated and nonsaturated samples of porous medium. Miscible flow is also considered as flow of a non-homogeneous fluid in a porous medium. Special concepts of head, as introduced by Lusczynski, are reviewed and modified in order to facilitate the determination of the velocity field in the zone of dispersion. The method described is applicable in principle to the migration of water in building materials exposed to sea water.

Notes: The Savannah area obtains most of its water supply from the principal artesian aquifer. The aquifer consists of limestones of middle and late Eocene age. Unflushed salty water is present in the lower water-yielding zones of the aquifer in the eastern part of the area and sea water is entering the upper water-yielding zones in the northeastern part of the area. The salty water in the lower zones and the upper zones is moving slowly toward Savannah because a cone of depression created by pumping has reversed the natural hydraulic gradient.

Notes: Eighty-one state agencies are engaged in hydrologic investigations. Many of these agencies have vigorous programs involving many phases of water resources; a few merely administer state funds in state-federal cooperative programs. The scopes of activities differ from state to state and include observation-well measurement, stream gaging, areal investigation, site investigation, statewide compilation, drilling test wells, cooperation with the U. S. Geological Survey, providing geologic support for hydrologic investigations, basic research, studying special problems, and publication of hydrologic reports.

Notes: Alluvial aquifers underlying Cigli Air Base near Izmir, Turkey are moderarely permeable (Pf= 1,600 gallons per day per square foot) but contain brackish waters. To circumvent the need for construction of an expensive electro-dialysis treatment plant, an area several miles to the north was explored for water of good quality to meet the base requirement of 600 gallons per minute.Forty-eight vertical resistivity soundings were made along six traverses. Profiles thus obtained delineated an area favorable for testing. Test drilling at or near three recommended locations resulted in three supply wells completed in an 11 to 23 foot thick gravelly sand 260 or more feet deep.The aquifer is artesian and tests indicated a field coefficient of permeability (Pf) in the range 5,000 to 8,500 gallons per day per square foot with declines to the south. Step-drawdown test data suggested that the design capacity of the three wells, from north to south, be 800, 500, and 400 gallons per minute, respectively.Water sampled during pumping tests is chemically good, with a maximum 490 parts per million total solids and a maximum 50 parts per million chlorides. The danger of salt-water encroachment is present, however, and well waters are being sampled routinely so that encroachment may be detected early and consequent remedial action taken.

Notes: The Hele-Shaw viscous flow model has been found to be a useful device in analyzing and studying certain types of ground-water flow problems. The discussion includes the theory of the Hele-Shaw model, scaling considerations, construction techniques, and examples of problems adaptable to this model such as recharge pits, seepage of saline water, tidal fluctuations and others.

Notes: Electric analog computers are playing an important role in the forecast of consequences of developing nonhomogeneous aquifers in Illinois having highly irregular shapes and boundaries and a wide variety of head and discharge controls. Analog computers are versatile and simple equipment, of low to moderate cost, with which ground-water development schemes can be rapidly and accurately tested and the relative merits of alternate choices of development can be appraised.The electric analog computer used by the Illinois State Water Survey consists of an analog model and excitation-response apparatus, i.e., waveform generator, pulse generator and oscilloscope. Analog models are regular arrays of resistors and capacitors and are scaled-down versions of aquifers and confining beds where present. Resistors are inversely proportional to the coefficients of transmissibility and vertical permeability aquifers and the coefficients of leakage of confining beds. Capacitors store electrostatic energy in a manner analogous to the storage of water in the aquifer. The behavior of the electrical network is described by an equation which has the same form as the finite-difference equation for nonsteady state two or three-dimensional flow of ground water. Electrical units (voltage, coulombs, amperes and seconds) and corresponding hydraulic units (feet, gallons, gallons per day and days) are connected by 4 scale factors.Excitation-response equipment force electrical energy in the proper time phase into the analog model and measure energy levels within the energy-dissipative resistor-capacitor network. Oscilloscope traces, i.e., time-voltage graphs, are analogous to time-drawdown or time-recovery graphs and describe drawdown or recovery conditions after a step function-type change in discharge. A catalog of time-voltage graphs provides data for construction of a series of water-level change maps. Close agreement of water-level declines determined with an analog computer and analytical methods for 3 selected idealized aquifer situations is noted with satisfaction.An electric analog model for the East St. Louis area was assembled. The sand and gravel aquifer in the East St. Louis area has an average thickness of 120 feet, an average width of 7 miles and an average length of 30 miles. The analog model for the aquifer consists of a regular array of 2800 resistors and 1350 capacitors. The scale of the model is 1 inch equals 2000 feet. Values of resistors range in magnitude from 2.2 megohms to 33,000 ohms; capacitors are 2500 micromicrofarads. The effects of the Mississippi River were simulated by terminating the portion of the electrical network along the river in an open circuit. Resistors large in magnitude were connected to terminals along the edge of the aquifer and to ground to simulate small amounts of sub-surface flow through bluffs. The accuracy and reliability of the electric analog computer was established by comparing past records of water-level declines and values of water-level declines determined with the analog computer. The electric analog computer was used to evaluate the practical sustained yields of existing pumping centers, to predict the effects of a selected scheme of development and to deter-mine the potential yield of the aquifer under assumed pump-ing conditions.An electric analog model for the Champaign-Urbana area was assembled. The sand and gravel aquifers in the Champaign-Urbana area are contained in the Mahomet buried bedrock valley which extends across the central part of Illinois from the Indiana border to the Illinois River Valley. The Mahomet buried bedrock valley averages about 12 miles wide in the Champaign-Urbana area and is largely filled with glacial drift ranging in thickness from 50 to 440 feet. Sand and gravel are encountered within the glac-ial drift at depths between 60 and 120 feet (upper aquifer), 140 and 170 feet (middle aquifer) and below a depth of 200 feet (lower aquifer). The upper aquifer is thin and discontinuous; the middle aquifer has an average thickness of 43 feet; and the lower aquifer often exceeds 100 feet thick. Till averaging 120 feet thick (upper confining bed) overlies the middle aquifer; about 30 feet of till (lower confining bed) separates the middle and lower aquifers. The analog model for the complex aquifer system consists of a regular array of 7500 resistors and capacitors. The scale of the model is 1 inch equals 1 mile. Values of resistors range from 1 to 68,000 ohms; values of capacitors range from 10e6 to lo-' farads. The analog model consists of 2 horizontal arrays of resis-tors and capacitors (lower and middle aquifers) and 1 hori-zontal ground wire array (water table) interconnected by two vertical arrays of resistors (lower and upper confining beds). The accuracy and reliability of the electric analog computer are being assessed. The computer will be used to predict the effects of future ground-water development and the practical sustained yields of existing pumping centers in the Champaign-Urbana area.

Notes: Transmissibility (T) may be estimated from the results of routine pumping tests of water wells when only discharge (Q), drawdown (s) and aquifer thickness (m) are known:

Notes: The following is a listing of abstracts of papers presented at recent meetings or appearing in other publications which are of interest to those in the field of ground water.Abstracts of papers presented during the 1963 National Water Well Exposition - San Francisco, California, September 29-October 3, 1963 (as published in the Water Well Journal, Vol. 17, No. 9).Analysis of Current Meter Data by Flow-Distribution Curves, Leve, Gilbert W., Geologist, U. S. Geological Survey, Jacksonville, Florida

Notes: This paper describes an electric log and what it can do for water well contractors and ground-water hydrologists. Electric logs furnish data on depth of hole, where casing should be set and perforated, static water levels, relative water-yielding properties of aquifers, water quality, character of formations encountered, etc. The electric log is a permanent record of a water well which can assist in planning future repair work.

Notes: In 1957, the High Plains Research Foundation, Plainview, Texas, initiated a full scale program to investigate all factors affecting the recharge of surface water to the ground-water formation. Some of the factors being investigated and studied are: rate of recharge, effects of solids contained in the lake water being recharged, maintenance practices, and evaluation of different filtering materials. This program was started because of concern about the declining water table and the potential of the lakes as a means of recharging the formation.Artificial ground-water recharge in the High Plains is accomplished by injecting water collected in playa lakes into a well constructed for this purpose. Either by gravity or pumping, water is placed back into the underground formation through the well casing in reverse of the pumping process. These wells can be used for irrigation crops as regular irrigation wells.

Notes: The determination of aquifer transmissibility by the bail-test method can be considerably simplified if proper attention is paid to the regular spacing of bailer cycles. The transmissibility calculation will then depend on the evaluation of the difference between two numbers, instead of on the evaluation and summation of a large set of numbers, one number for each bailer cycle. The mathematical development on which this method is based is given briefly and a table listing the sums of the reciprocals of the natural numbers, which is used in the simplified determination, is also presented.The formula for the recovery of the water level after repeated bailing of a well completed in a confined aquifer (Skibitzke, 1958) may be written (Ferris et al., 1962):

Notes: The modern water well contractor is a combination structural engineer, mechanic, geologist and sanitarian. Contractor's skills and accumulated knowledge should be assembled within an area and used as the basis for design and water well specifications. Engineering a water well should have the primary objective of obtaining an adequate supply of potable water, with equal importance placed upon the protection of the source of supply.The drilling of a test bore should be included in the design of every water well. A properly drilled and accurately logged test bore can determine exact design features and equipment requirements. In an area where formation samples may be deceiving and where a more accurate log is required, it is possible to contract for an electric log of the test bore. When it is essential to obtain truly representative samples in an uncontaminated form, core samples may be taken as the test bore is being drilled.Well drillers have the right in most places to procure water for the consumers in the quantities available, and along with this right, they have the obligation of preventing contamination or depletion of the source of supply. It is the well drilling contractor's position to either directly design his projects or consult with the designing agent, making recommendations that will enhance quality rather than convenience or economy.The water well driller should acquaint his customer with modern construction procedures and modern water well design just as he has become aware of building codes and architectural specifications in the construction of buildings and homes. Contractors must keep pace with the achievements of technical people associated with the water well industry by self-education and incentive. The water well industry should be, and is, proud of its responsibility.The design and construction of a water well is no longer limited to the procurement of underground water, but also entails certain obligations on the part of the designer or contractor. Every industry, particularly those who produce consumer goods, have certain responsibilities, but none of their products are as absolutely essential to the existance of life or have a more important role in the social and economic welfare of mankind than the product of the water well drilling industry.No other group has more knowledge of the vast underground water resources or the importance of the

Notes: “Hidden recharge” is defined as subsurface percolation of water from basin-margin mountains directly into aquifers of the valley basins. It is an important, and sometimes neglected, item in hydrologic equations. Locally, geologic conditions permit inter-basin circulation of ground water. The concept that ground-water basins necessarily terminate at the contact between alluvium and hardrock is not tenable.

Notes: The problem of integrating or coordinating surface water and ground-water use is becoming serious in many areas where the two supplies are hydraulically connected. Because surface waters were generally developed first in the West, later development of connected ground-water supplies has tended to devaluate the prior appropriations on the streams. Legally, those withdrawing such ground water may be in jeopardy. However, the highest beneficial use of the total water resources can only be obtained through a combined or integrated use of both surface and ground water. A simple hypothetical stream-aquifer situation is used to illustrate the influence of ground-water pumping upon surface flows and water available for diversion. One example of a possible solution is presented. Legal and economic factors must also be considered in designing the best physical situation.

Notes: Resistance network analogs (R-analogs) permit solution of ground-water flow systems in media that may be uniform or non-uniform, isotropic or anisotropic, and saturated or unsaturated. Two-dimensional as well as axisymmetric systems can be represented on the analog and complex boundary conditions can easily be simulated. Only steady-state systems can be analyzed with the R-analog. However, systems with moving water tables whereby the rate of movement of the water table is controlled by the flow system below the water table can be solved as a succession of steady states. To capitalize on the special feature of R-analogs, i.e. essentially unlimited opportunity for control of the resistance between any two nodes, use of calibrated variable resistors is desirable. R-analogs are specially adapted to obtain solutions of individual flow systems, of which a vertical cross section is simulated on the analog. In the analog model, resistances are inversely proportional to hydraulic conductivities or transmissibilities, electric current rates are proportional to rates of water flow, and electric potentials are proportional to the sum of pressure head and elevation head. R-analogs may be used to analyze the flow system of a pumped well, a groundwater recharge facility, a series of parallel drains, a seeping dam, a surface stream feeding the ground water, etc. Examples are presented of flow problems involving free-surface development, simultaneous occurrence of saturated and unsaturated parts of the medium, moving water tables, and determination of transmissibility distribution and safe yield of ground-water basins. The application of R-analogs in developing realistic cause-and-effect relationships for use with resistance-capacitance analog models of entire ground-water basins, is discussed and exemplified.

Notes: Numerous articles have been written in the past on the methods and techniques of resistivity and seismic exploration in ground-water studies, however, few articles ever show why a specific type of survey was chosen and what the results or relative costs of such a survey were. In this paper, the authors have attempted to illustrate why particular techniques are chosen and indicate the actual results of the study. In addition, the general cost of the study is mentioned so that one might compare the cost versus other savings or benefits on the project.The four studies indicate that savings on projects may vary from many thousands of dollars to good will depending on the nature of the problem to be solved.

Notes: Describes investigation made to determine cause of excessive corrosion of construction materials of wells supplying domestic water to communities bordering atomic energy plant in South Carolina. Corrosion resulted from natural corrosiveness of soft water with high carbon dioxide and oxygen contents. No effect from atomic energy plant was indicated.

Notes: Water-bearing properties of crystalline rocks are dependent on the occurrence of joints and faults and the extent of weathering. Interstitial openings caused by weathering are mostly at depths of less than 100 feet. Joints are less abundant and openings along joint planes are smaller as depth increases. Openings along fault surfaces also tend to close with depth. These geological observations which indicate a decrease in rock permeability with depth are verified by a study of well yields and water-injection tests. Mean yields per foot of well are 0.23 to 0.30 gpm at 100 feet but only 0.013 to 0.04 gpm at 1000 feet. Mean injection rates per foot of drill hole under 100 psi pressure are 0.11 to 0.4 gpm at 100 feet but only 0.014 to 0.038 gpm at 1000 feet. Median values of both well yields and injection rates are from one-half to one-third of the mean values. Geologic structure is more important than rock type in determining yields and injection rates. The decrease in rock permeability with depth indicates an increase in the unit cost of water with depth. The optimum depth of a well is, therefore, determined largely by economic factors. Unless geologic factors are favorable, wells in crystalline rocks should be less than 600 feet deep. In general, domestic wells should be less than 150 to 250 feet deep.

Notes: This paper is essentially a summary of observations and conclusions of a 3 year hydrologic study (Skinner, 1963) in Prospect Valley, Colorado. A general description of the area is presented, including a brief review of the geology and hydrology with special emphasis on the surface and ground-water supplies for irrigation. The effects of an artificial ground-water recharge operation on ground-water levels and ground-water quality are discussed. Based on historical water deliveries some water resource management aspects are proposed involving conjunctive use of surface and ground-water supplies.

Notes: The great and continued expansion in the utilization of ground water has resulted in an ever increasing need for professional people to enter the field of ground-water resource evaluation and management. Prominent scientists and educators have indicated that the small number of graduates each year is inadequate to meet the current needs much less the future demands for ground-water geologists and engineers. It has been suggested that this deficiency is due in part to the lack of suitable programs of university and college instruction. However, statistical data on the educational and academic research facilities in ground-water geology and hydrology outside the United States and Canada have not been available for study. Statistical data for institutions in the United States and Canada were published in May 1961 (Hackett and Walton, 1961).To obtain data on formal course work and research facilities, the Research Committee of the Technical Division of the National Water Well Association circulated a Questionnaire to appropriate educational institutions outside the United States and Canada in March 1963. This paper is based on completed questionnaires and provides statistical data on university and college activities in the field of ground water. It is hoped that the statistical and descriptive information embodied in this report will provide a suitable background for those who wish to assess the adequacy of available educational and academic research facilities relating to ground-water hydrology and geology.In March, 1963, the Research Committee of the Technical Division of the National Water Well Association mailed a questionnaire on educational facilities in ground-water geology and hydrology to some two hundred foreign institutions of higher learning. By October 1963, some fifty institutions had replied to the questionnaire which was a simplified version adapted from a prototype drafted by James E. Hackett and William C. Walton (1961), and used to make a similar survey on U.S. and Canadian universities. The contents of the questionnaire are given in Table 1.While the response to the questionnaire may seem small at first sight, since only 25 percent of the polled institutions replied, the initiative taken was worthwhile and some interesting conclusions may be drawn from the result. In the first place, the relatively poor participation may be explained, to a large extent, by the fact that a great number of the foreign institu-tions that were questioned do not have a specific interest in ground water. Furthermore, the questionnaires were sent to the schools of engineering or the departments of geology of the institutions, in the hope that there would be an exchange at the local level. This was accomplished in some cases, as may be seen from a summary of the main results in Table 2, but not always. On the other hand, although English is a major international language, it is still not mastered by all foreign scientists and engineers. This may explain why some individuals may have been reluctant in answering to the request for information. We should also realize that the pattern of higher education in some countries is different from ours, which again leads to difficulties in filling out a questionnaire tailored to our needs. It was very rewarding for us to see that France had the largest participation rate (60 percent) of all countries. Probably this is due to the fact that this country apparently emphasizes the subject of hydrogeology more than any other but also, we believe, because we had sent a special French questionnaire to the French institutions. Also, as a result of this policy, the answers were more detailed than those of most of the other participants. It is safe to assume that, if we had written in the native tongue of each country, we would have received more complete answers.Table 2 has been divided somewhat arbitrarily into five classes, according to the strength of the curriculum in subjects related to ground water.Class I: unusually strong programClass II: strong programClass III: significant programClass IV: small programClass V: no programIt is very difficult to draw a well defined boundary between these classes and between some institutions in particular cases, and the five classes have been allotted ten members each for the sake of simplicity. Also, the classification is not the outcome of a contest but a mere indicator of relative interest in the subject of ground water. Several institutions which belong to Classes IV and V have explicitly asked to be informed about the conclusions drawn from this survey, which would tend to prove that they have an interest in the subject but that financial means or other motivation are lacking.A quick glance at Table 2 shows that in Western

Notes: Approximately 4 pounds of refuse per capita per day are produced in the United States. The term refuse, as used here, refers to the useless, unused, unwanted, or discarded solid waste materials resulting from normal community activities; refuse includes such materials as garbage, rubbish, ashes, street refuse, dead animals, and solid industrial wastes (Anon., 1958). Thus, every day our urban population produces over 400,000,000 pounds of refuse that must be disposed of by dumping on land, grinding and disposal with sewage, incineration or that must be made reusable by one or more reclamation processes. Over 1400 communities dispose of their refuse by sanitary landfill techniques, i.e., compaction and covering with compacted earth on suitable land by use of mechanical equipment such as crawler type tractors (Figure 1). Many thousands more dispose of this material in open dumps on land without the degree of sanitary control recommended by health agencies (Figure 2).Wherever refuse is deposited on land, the potential impact on surface waters or subterranean aquifers may be significant. This can be better appreciated when one considers, for example, that ordinary community refuse may have a 5-day BOD of 14,000 to 180,000 ppm and an alkalinity (to MO as CaCO3) of 2600 to more than 23,000 ppm, as shown in Table 1 (Anon., 1952a). In one study bacteriological examination of landfill material showed an average of 740,000 coliforms per gram of refuse. The leachate from a landfill has been found to have a 5-day BOD from 6 to more than 7000 ppm (Carpenter and Setter, 1940; McDermott, 1950).The question is, of course, what does this mean translated into terms of potential ground-water pollution? And further, when this potential is known, what then are the practicalities involved in present disposal practices and their implications with respect to the development of existing and future ground-water pollution problems?

Notes: Using a simple integral transform suggested by Roy and Jain (1961), methods of interpretation of electrical potential data for a point source in the presence of one or two infinitely long horizontal cylinders are developed. The methods are applicable to electrical surveys of long filled channels of semi-circular cross-section or of buried cylindrical ore bodies.

Notes: On sait que l'effet perturbateur, sur une trace sismique, d'un fort réflecteur proche de la surface peut être en grande partie éliminé en convoluant la trace par un opérateur, dit “d'anti-résonance”, très simple, puisqu'il ne comporte que trois termes.Nous nous proposons de montrer que pour éliminer, de la même manière, l'effet d'un nombre quelconque de réflecteurs, il existe également des opérateurs d' anti-résonance à un nombre fini de termes, et nous donnerons les formules permettant de construire ces opérateurs.Les formules obtenues permettent également de vérifier qu'une trace sismique (symé-trisée par rapport à l' origine) doit être une fonction d' auto-corrélation, et fournissent, de plus, l'expression et l' interprétation physique d'une fonction dont la fonction d'auto-corrélation donne la trace sismique.