Abstract: A method is provided for conducting an electromagnetic induction survey of a geological formation penetrated by a borehole lined with a conductive casing. The method includes positioning a transmitter in the borehole, whereby the transmitter generates a transmitter magnetic moment, and positioning a distant receiver external of the borehole to detect a magnetic field induced by the transmitter, whereby the distant receiver is disposed across part of the formation from the borehole. Furthermore, an auxiliary receiver is positioned in the borehole proximate the transmitter to detect a magnetic field induced by the transmitter and attenuated by the conductive casing. Subsequently, a first casing attenuation factor that is applicable to the magnetic field measured by the auxiliary receiver is determined from a ratio of the measured magnetic field at the auxiliary receiver and the transmitter magnetic moment.

Abstract: An antenna assembly for an induction logging tool for use in a drilling operation. The assembly includes an outer pressure housing, a coil former within the pressure housing, magnetic cores mounted in the housing, a core carrier within the coil former and the pressure housing which carries the magnetic cores, and shock-absorbing mountings on the core carrier for the magnetic cores.

Abstract: A passive geophysical prospecting method and apparatus are provided. The apparatus has an antenna for detecting electromagnetic radiation naturally emanating from the Earth's surface and generating an electrical signal from the detected electromagnetic radiation while traversing the Earth's surface by a vehicle traveling over land or water or in an airplane. The electrical signal is filtered of frequencies below 65 Hz, preferably above 100 Hz and more preferably below 800 Hz, and above 12,000 Hz, preferably above 8,000 Hz, to generate a filtered signal. The filtered signal is converted to a prospecting voltage signal. The prospecting voltage signal is then compared to a set voltage and a difference signal is generated, recorded and analyzed.

Abstract: A method for reducing noise in borehole electromagnetic telemetry systems in which a signal receiver is positioned at a distance from a drill site borehole at which the signal receiver couples strongly to a signal from a signal transmitter disposed in the borehole and weakly to drill site noise emanating from the drill borehole, a noise receiver is positioned at a distance from the drill site borehole at which the noise receiver couples substantially only to magnetotelluric and/or drill site noise, the contributions of the magnetotelluric noise and drill site noise are determined, and subtracted from the signal received by the signal receiver, resulting in a reduced noise signal.

Abstract: The invention is a well radar for detecting, by electromagnetic wave reflection, resistivity horizons in production zones in oil wells. Transmitter and receiver antennas are combined in a tubing string antenna module. Two dipole transmitter antenna are positioned in a first position on either side of the tubing string antenna module. A first directionally sensitive group of four dipole receiver antennas is positioned in a second positioned so that the receiver antennas have even angular separation. Likewise, a second directionally sensitive group of four dipole receiver antennas is positioned in a third position opposite the first directionally sensitive group.

Abstract: A casing pipe is inserted into a drilled hole reaching the inside of a confined aquifer in which groundwater is stored and flows or a position near the confined aquifer. A measuring device measures an electromagnetic field at the distal end of the casing pipe. An analyzing device analyzes data concerning the electromagnetic field measured by the measuring device to sense motion of ground pore water, thereby predicting rapid motion in the earth's crust, such as a volcanic eruption, an earthquake, a landslide and ground collapse. The casing pipe is an electrically conductive pipe having a non-magnetic screen portion formed at the distal end thereof so that recycling groundwater passes through the screen portion. The measuring device includes an electromagnetic field sensor placed in the screen portion and the conductive casing pipe as an electrode for measuring an electric potential relative to an electric potential at the earth's surface detected with a reference electrode.

Abstract: A shielding method and apparatus for an antenna disposed on an elongated support adapted for disposal within a borehole. The shield providing predetermined attenuation of one or more electromagnetic energy field components as the field components interact with the shield. The shield composed of a flexible strip or cylindrical body and respectively comprising a transverse conductive element or a transverse slot therein. The shields being adapted to cover an antenna mounted on the support. The shields being compatible for use in conjunction with saddle, tilted coils or multi-layered tri-axial coils to produce a pure transverse magnetic dipole electromagnetic field. The shields are also used in methods for shielding an antenna disposed on a support to provide predetermined attenuation of an electromagnetic field component as the field components interact with the shield.

Abstract: Most mines and underground facilities employ standardized construction techniques and materials. Such also cannot avoid having some above ground openings to receive utilities, fresh air, supplies, etc. Those or other surface openings are also universally used to discharge ground water, wastes, and other materials. Typical underground facilities have abundant electrical wiring and power demands, both of which can be detected at the surface. Levees with leakage pathways also form electrical conductors. When properly illuminated with remotely generated electromagnetic (EM) radiation, many of these features will “glow” or reradiate the radio energy in an electronic signature unique to the underground facility. Synchronized EM-gradiometer transponders are situated nearby on the ground surface to collect and analyze the “glow”. Alternative transmitting devices further includes ways to generate the illumination, and computers for characterizing the return signatures.

Abstract: A method and system for determining the location of a microseismic event is disclosed. An electromagnetic sensor measures the electromagnetic energy which is caused by a microseismic event. Seismic data from the microseismic event is measured and recorded using plurality of ground motion sensors. The time at which microseismic event occurred is estimated based at least in part on the time at which electromagnetic energy caused by the microseismic event is received by the electromagnetic sensor. The location of said source of the microseismic event is determined using the estimated occurrence time and the time at which the seismic energy arrived at the ground motion sensors. A method of triggering a seismic recording device is also disclosed. The electromagnetic energy from a microseismic event is measured and recorded using an electromagnetic sensor. The time at which the microseismic event occurred is estimated based on the measured electromagnetic energy.

Abstract: An apparatus and method for passively determining physical characteristics of subterranean geological formation which for example bear oil or gas or commercial important ore deposits such as precious metals. The apparatus includes an antenna for acquiring low frequency signals naturally emanating from the earth. The received signal is first put through a low pass filter and buffer and then converted from analog to digital, stored in a memory buffer, converted to a frequency spectrum by a Fourier transform, and then further processed to display geophysical information versus the depth of such discontinuities.

Abstract: A spoken word-producing detector identifies objects by comparing signatures of detected objects with stored signatures of known objects. When the signatures compare, the detector produces stored word sounds associated with the detected object identifications. An annunciator produces the words from pre-digitized human voice sounds. A screen displays the words.

Abstract: A simple and compact method and apparatus for detecting high frequency electric fields, particularly in the frequency range of 1 MHz to 100 MHz, uses a compact toroidal antenna. For typical geophysical applications the sensor will be used to detect electric fields for a wide range of spectrum starting from about 1 MHz, in particular in the frequency range between 1 to 100 MHz, to detect small objects in the upper few meters of the ground. Time-varying magnetic fields associated with time-varying electric fields induce an emf (voltage) in a toroidal coil. The electric field at the center of (and perpendicular to the plane of) the toroid is shown to be linearly related to this induced voltage. By measuring the voltage across a toroidal coil one can easily and accurately determine the electric field.

Abstract: A system for detecting precursor seismic electromagnetic waveforms.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: In order to compensate for magnetic field drift and shorten the overall scanning time, total number of pulse sequences of data acquisition for magnetic field drift compensation Md is less than the repetitive number of imaging data acquisition pulse sequences Im, and a pulse sequence of data acquisition for magnetic field drift compensation Md is inserted between imaging data acquisition pulse sequences Im.

Abstract: The location of underground objects such as pipes and conduits are located by detecting electrical signals emitted by the underground objects where the radiated signals include spread spectrum modulated RF signals. The system can operate in a passive or active mode, and in the active mode pseudo-noise (PN) generators can be employed or frequency-hopping can be employed. The use of spread spectrum minimizes or eliminates conflicting signals radiated from a plurality of underground objects and can improve signal to noise ratio of the detected signals.

Abstract: A method for nondestructive, three-dimensional detection of structural elements in structures, especially those made of concrete or similar materials, allows an area to be investigated to be scanned areawise using ultrasound and by recording high-frequency, travel-time-dependent data for the individual points. In an imaging method, the respective volume image of the area being investigated is determined. This method is improved in such fashion that the accuracy of the location of structures is improved. It is proposed that the area to be investigated be scanned by both ultrasound and radar and that a structural representation of the area investigated be performed both on the basis of data acquired using sound and on the basis of data acquired using radar, with these two representations being calibrated.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: An apparatus and method for passively determining the depth and thickness of a subterranean geologic formation bearing hydrocarbons, e.g., oil and/or gas, or commercially important ore deposits, e.g., precious metals. The apparatus has an antenna to pick up extremely low frequency signals naturally emanating from the Earth's surface. In a preferred embodiment, the received signal is amplified and filtered. The signal is then modulated onto a carrier wave. The modulated signal is then filtered to eliminate one of the sidebands, for example, the lower sideband. An oscillator generates a tuning frequency which is then beat against the filtered, modulated signal in order to tune to a particular frequency. The oscillator sweeps through the range of frequencies, e.g., in the upper sideband portion of the filtered, modulated signal.

Abstract: A diastrophism detection method and an apparatus therefor are provided which is capable of predicting a position of occurrence of diastrophism such as an earthquake or the like, a scale thereof, time thereof and the like with increased accuracy without being affected by various artificial and natural noises and being effectively put to practice utilizing a simple and objective judgment procedure and by means of equipments simplified in structure and reduced in cost. A VHF radio wave beyond a line-of-sight distance through a plasma density distribution abnormality zone temporarily formed in the ionosphere during diastrophism such as an earthquake or the like is detected in the form of abnormal propagation, resulting in a position of diastrophism below the plasma density distribution abnormality zone, a scale thereof, time thereof and the like being judged.

Abstract: A method and apparatus for detecting underground liquids is disclosed in which the electrical potential generated by a seismic shock is detected and measured with respect to a base point insulated from the earth.

Abstract: The present invention relates to realize a tectonic activity monitoring equipment providing apparatus and method to detect a feeble electromagnetic wave occurred by the tectonic activity with a high signal-to-noise ratio (S/N) and to predict earthquake and volcano eruption. The apparatus and the method for monitoring tectonic activity of the present invention comprises electromagnetic wave sensors and one or more of amplifiers for amplifying signals detected by the sensors. And an observation frequency for detecting electromagnetic wave occurred from tectonic activity is set to a frequency between a few tens Hz and 1 kHz so as to eliminate the influence of noises of a strong radiation power less than a few tens Hz and tropical thunder noises of more than 1 kHz of higher order modes propagating between the earth and the ionosphere.

Abstract: An apparatus and method for performing geological mapping utilizes an HF transmitter to heat ionospheric electrons to cause the current in an overhead electrojet to be modulated, thereby injected a low frequency EM signal into the Earth-ionosphere waveguide. A sensor measures vector values of electric and magnetic fields in an area to be surveyed. The measured vector values are provided to a processor that creates a conductivity map of the surveyed area based on the measured vector values.

Abstract: An apparatus and method for passively determining the depth and thickness of a subterranean geologic formation bearing hydrocarbons, e.g., oil and/or gas, or commercially important ore deposits, e.g., precious metals. The apparatus has an antenna to pick up extremely low frequency signals naturally emanating from the Earth's surface. In a preferred embodiment, the received signal is amplified and filtered. The signal is then modulated onto a carrier wave. The modulated signal is then filtered to eliminate one of the sidebands, for example, the lower sideband. An oscillator generates a tuning frequency which is then beat against the filtered, modulated signal in order to tune to a particular frequency. The oscillator sweeps through the range of frequencies, e.g., in the upper sideband portion of the filtered, modulated signal.

Abstract: An infrasonic frequency resonant circuit and method for use thereof. An electric power distribution system is employed both as antenna for ISF signals and as a source of inductive reactance for a resonant circuit tuned to a band within the ISF spectrum. A capacitor is placed from the neutral conductor to the ground conductor at an ac power outlet in a structure to form a resonant circuit ordinarily tuned to a band within the ISF spectrum. An ISF spectrum analyzer is connected to the neutral and ground terminals of the resonant circuit to visualize ISF electromagnetic signals induced on the electric power distribution system in both the frequency domain and the time domain and so as to be more readily evaluated.

Abstract: A method of detecting precursor seismic electromagnetic waveforms and predicting future seismic activity in the form of an earthquake by placing a detector including a dielectric material in contact with the earth. The detector receives at the dielectric material precursor seismic electromagnetic waveforms traveling within the earth emanating from a region of seismic activity. A sensor responsive to the dielectric material senses a series of individual discrete signals imposed by the waveforms at the dielectric material wherein each of the signals has the characteristic of a rise time that is shorter than its fall time. Alternatively, the discrete signals may be a single discrete signal characterized by a plurality of overlapping waveforms. Then predicting based on the series of the signals the occurrence of the earthquake.

Abstract: A system for assistance in landing a helicopter and for the detection of electro-magnetic anomalies utilizing helicopter blades as carriers of receiving devices in a wide spectrum of electro-magnetic fields with a predicted sensitivity and resolution far in advance of previous systems.

Abstract: A method and apparatus for predicting the occurrence of an earthquake in a monitored area as described by detecting the vertical component of the Earth's magnetic field at a plurality of pairs of spaced points, the spacing "d" between the points of each pair being from 450 to 2,300 meters in a first horizontal direction, the spacing "Y" between each pair of points being between 450 and 25,000 meters in a second horizontal direction substantially perpendicular to the first horizontal direction.

Abstract: A method and apparatus for estimating the earth's resistance (conductivity) as a function of depth using electroseismic prospecting (ESP) or inverse ESP techniques. Resistance is determined by the frequency-dependent attenuation of reflected EM signals which are produced by application of seismic signals to the earth. A seismic wave is generated by conventional means into the earth, and EM waves are generated back to the surface by different reflectors at different depth levels. This propagation attenuates the high frequencies preferentially. EM waves generated at lower depths are further attenuated relative to those waves generated at more shallow depths. The method and apparatus determines the difference in spectral content between the reflected signals from different horizons based on their relative attenuation and uses this difference as a direct measure of the conductivity between the horizons.

Abstract: The invention is directed toward the elimination of the effects of electromagnetic coupling between pairs of receivers. The preferred embodiment encompasses the measurement of resistivity and other electromagnetic properties of earth formation in a borehole environment. The invention also incorporates techniques for eliminating the effects of receiver antenna drift and the effects of power variations of two or more transmitters.

Abstract: An apparatus for measuring transient earth current includes a detection electrode and a second electrode disposed beneath the surface of the earth in vertical alignment with one another at depths greater than those to which electromagnetic waves generated above the surface of the earth having commercial power line frequencies penetrate, such that the electrical resistance between the detection electrode and the second electrode is on the order of several tens of thousands of ohms, and a charge detector for detecting only high frequency components of a current flowing between the detection electrode and the second electrode. On the basis of these detected high frequency components, the likelihood of an occurance of an earthquake may be determined.

Abstract: A method and apparatus for passively determining the depth of an anomaly using means for monitoring a broad spectrum of frequencies and analyzing the amplitude and modulation of a time and/or location varying signal within discrete bands of frequencies to determine the depth of a spatial or temporal anomaly. A means for recording and mapping substerranean features based on an ascending or descending sequence of frequency measurements is also disclosed.

Abstract: A method and apparatus for nuclear logging, and in particular, neutron porosity logging is presented. In accordance with the present invention, a novel programmable gain amplifier circuit and a novel peak detector circuit are used in conjunction with other electronic circuitry to provide borehole formation logs in a nuclear logging tool.

Abstract: The present invention is used to cancel a narrow band noise of know frequency, such as 60 Hz noise generated by powerlines, in electromagnetic receiving equipment. A cancelling antenna is wrapped around the sensing antenna of the electromagnetic receiver equipment. The cancelling antenna is provided with an alternating current signal of the same frequency as the ambient powerline noise. The cancelling antenna produces an electromagnetic field that is 180 degrees out of phase and of equal amplitude to the ambient powerline noise, as measured by the sensing antenna. The alternating current is produced by a noise antenna, a phase-locked loop and an amplifier. The noise antenna receives the ambient powerline noise, the phase-locked loop locks onto and tracks the frequency of the noise, and the amplifier provides the necessary amplification.

Abstract: A geophysical prospecting method of measuring potentials existing in the air in the area of the lower atmosphere between about one and ten meters above the surface of the earth in order to detect petroleum accumulations and mineral deposits below the surface of the earth. The method mounts a detector device is mounted on the front bumper of an off-the-road vehicle and moves the vehicle across the surface of a given area of earth in a more or less continuous fashion. Changes in the electron flow through the ion field at the surface of the earth to increased and decreased resistivity values in the crust of the earth are recorded.

Abstract: An apparatus for sensing the electrical potential of a positive electrostatic field which is primarily below the surface of the earth, and observing the changes in a series of each reading is accomplished by means of an instrument employing a column of mercury in a small-diametered quartz tube, which is open on its lower end with means connecting to the other end for changing the level of mercury within the tube. A conductive coating on the exterior of the tube is connected to an electrometer and the coating is arranged to be selectively grounded or ungrounded in conjunction with changing the level of the mercury column. The readings for the electrometer provide a measure of the electrostatic field.

Abstract: A method for detecting earthquakes comprises the steps of picking up pre-earthquake long waves or earth currents at four or more observation points located underground or at the sea bottom, carrying out a computation based on the interrelation among the so-obtained= signals to obtain the three-dimensional distribution of the sources and intensities of the long waves or earth currents, and predicting the focal region, scale and time of occurrence of earthquakes from the time-course variation in the so-obtained three-dimensional image of the wave source.

Abstract: A method of electroseismic prospecting is disclosed for detecting either the presence of two immiscible fluids present in a porous subterranean formation or the presence of a high-permeability rock formation including a substantially aqueous phase therein. A seismic impact produces an acoustical wavefront that results in an enhanced electromagnetic signal when it encounters either types of the above-described formations. This resulting enhanced electromagnetic signal is detectable as an indication of a likely hydrocarbon deposit, thereby giving additional data information with conventional seismic data to the geophysical prospector.

Abstract: The present invention relates to a system for acquisition and separation of the effects of simultaneous sources of electromagnetic field. According to the invention the system comprises an array of n pick-ups (1a . . . 1e) connected to registration means (2), the minimum number n of pick-ups per array being equal to 2s+2, where s is equal to a number of simultaneous sources to be analysed.

Abstract: A geophysical prospecting detector device and method of measuring potentials existing in the air in the area of the lower atmosphere between about one and ten meters above the surface of the earth in order to detect petroleum accumulations and mineral deposits below the surface of the earth. A detector device is mounted on the front bumper of an off-the-road vehicle and the vehicle is moved across the surface of a given area of earth in a more or less continuous fashion. Changes in the electron flow through the ion field at the surface of the earth to increased and decreased resistivity values in the crust of the earth are recorded.

Abstract: An antenna element such as a monopole, dipole or loop antenna is located in the earth or on the floor of the sea so as to receive pre-earthquake electromagnetic waves generated prior to the occurrence of an earthquake. Unwanted noise waves propagating in the air such as man-made noise are effectively eliminated by a reflector laid on the surface of the earth or by the sea water and only the required pre-earthquake waves are detected by the antenna element, whereby earthquakes can be predicted reliably.

Abstract: A method and apparatus for locating and evaluating surface and subsurface anomalies by detecting, monitoring or measuring transient or local variations respectively which occur in an alternating component of a vertical current having a frequency characteristic which emanates from the earth'surface in the region being monitored or measured. For locating fixed anomalies, local variations which occur in the amplitude, frequency and frequency modulation of the alternating component of the vertical current are measured. For detecting the passage of moving or transient anomalies, a stationary detector is positioned to detect any change in the vertical alternating current leakage in the vicinity of the detector which is caused by a moving or transient anomaly such as a submerged submarine, seismic activity, or sustained severe wheather. For accuracy enhancement and redundancy, simultaneous measurements of the signal strength in multiple frequency bands may be used.

Abstract: The method of geophysical prospecting of polymineral ore bodies including registering pulsed electromagnetic radiation generated by the ore bodies under the action of elastic waves excited in the rock block. The radiation is registered as pulse bursts, each burst corresponding to one ore body. The shape of a pulse corresponding to the ore body under investigation is compared with the shapes of pulses corresponding to ore bodies of the known mineral compositions, and one similar pulse is selected from these pulses. Then a pulse from the burst corresponding to the ore body under investigation is subjected to the Fourier transformation to obtain the pulse height-frequency spectrum of this pulse, which is compared with the pulse height-frequency spectrum of the selected pulse, and when at least two frequencies of the maximums of the amplitudes of these respective spectra coincide, there is established correspondence between the mineral compositions of the known ore body and of the ore body under investigation.

Abstract: The present invention relates to an apparatus for detecting magnetic and electromagnetic waves or fields through use of non-superconducting materials. The present invention relates to apparatus which are used to measure such fields in order to predict earthquakes, volcanic eruptions and other violent earth movements which generate substantial abberations in magnetic and electromagnetic fields. The present invention can be used to detect any fluctuating magnetic or electromagnetic fields regardless of their origin. The present invention incorporates the use of antennae for the electromagnetic components and coils to detect magnetic fields, in conjunction with electronic elements involving amplification, smoothing elements, frequency response networks, networks to make frequency response uniform within the band and notch filters where necessary.

Abstract: The present invention is a well logging receiver coil system which includes a coil. The system also includes a variable capacitor connected across the coil to form a resonant circuit tuned to a predetermined frequency. The coil in the presence of an electromagnetic field has a current induced therein representative of the strength of the electromagnetic field. A pick-off circuit is connected to the coil in a predetermined manner and provides a signal representative of the strength of the magnetic component of the electromagnetic field substantially unaffected by the electrical field component of the electromagnetic field.

Abstract: Method and apparatus determining the water saturation of a petroleum reservoir earth formation include transmitting electromagnetic energy in the earth formation from within a borehole traversing the earth formation and at least two frequencies within a preferred range of frequencies. The electromagnetic energy is received at two locations from the earth formation and within the borehole. The water saturation of the earth formation is derived from the received electromagnetic energy.

Abstract: Method and apparatus for use in introducing electromagnetic energy into subsurface earth formations and acquiring measurements relating to propagation of such energy therethrough. A logging tool body includes a plurality of transmitter and receiver antenna assemblies positionable against the borehole wall. Construction of each antenna assembly includes a cavity-backed slot resonated by lumped elements, the slots being oriented generally with their elongate dimension transverse to the tool body. The transmitters and receivers are interconnected, respectively, to a downhole source of electromagnetic energy operating nominally at 200 MHz and to appropriate receiver circuitry. Formation dielectric constants are determined from phase differences and relative amplitude ratios of energy from the formation incident on the receiver antennas.

Abstract: A method for locating and evaluating surface and subsurface anomalies. Solar wind results in a multi-frequency, high energy ionic impingement at the terrestrial poles of the earth. Monitoring the activity of the solar wind allows the determination as to when the activity produces a vertical alternating current leakage (solar alternating current) due to the ionic impingement. When the vertical current leakage is in a proper range which can be measured and which reflects and represents surface and subterranean anomalies, a predetermined region of the earth to be prospected is traversed. Local variations which occur in the amplitude, frequency and frequency modulation of the vertical alternating current leakage due to the ionic impingement of solar winds at the terrestrial poles (solar alternating current) is measured. The measurements are recorded in correlation with the spatial relation to the points of measurement to determine significant measurements indicative of surface and subterranean anomalies.

Abstract: A direct and continuous receiving and measuring device for electrical, magnetic and acoustic signals comprises an amplifier stage and a broadband filtering stage at the input, a local oscillator for supplying a reference signal, a measuring stage, a mixer to which the local oscillator and the broadband filtering stage are connected and a low frequency filtering stage connected to the mixer.The invention also includes the process of carrying out the measurement.

Abstract: A method of seismic prospecting using electromagnetic grounded antennas to detect electromagnetic waves that are produced from acoustic waves in the earth's formation. Seismic waves reflected by a formation in the earth are converted into electromagnetic waves in the vicinity of the antenna according to the streaming potential theory. The antenna has two electrodes which detect the horizontal component of the electromagnetic waves, thus providing additional seismic information that is not readily available using standard geophones. Antennas are also not subject to coupling problems and thus provide more accurate information than traditional geophones. For example, using multicomponent detection, all three components of the seismic pressure gradient can be detected.