JP2009025104A - Reflection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To identify a buried object with high accuracy and clearly by devising an arrangement of an oscillator in a reflection method exploration in which a buried object and a stratum structure in a shallow underground can be easily explored from the ground surface.
[Solution]
The reflection method exploration system 100 of the present invention is installed on the ground surface and generates an oscillation 110 (transverse wave) in the lateral direction with respect to the ground, and is reflected at a buried object or a layer boundary in the ground to reach the ground surface. A detector 120 for detecting the reflected wave and a position estimation device 130 for estimating the position of the buried object or the formation boundary from the detected reflected wave. It is characterized by being placed at a position that is not affected by.
[Selection] Figure 3

Description

  The present invention relates to a reflection method exploration system for exploring buried objects and strata structures in the underground using a reflection method.

  Conventionally, reflection method exploration has been used in which a buried object buried in the ground is estimated nondestructively without digging up the ground. This is a technique for oscillating an elastic wave with physical vibration toward the ground and estimating the position of the buried object through a reflected wave from the buried object.

  As an embodiment using such a reflection method exploration, a technique is disclosed in which a plurality of detectors and oscillators are linearly arranged and a transverse reflected wave generated by the oscillator is measured (for example, Patent Document 1). ).

  FIG. 7 is a layout diagram showing a conventional layout example of each component in the reflection method exploration. FIG. 7A shows a plan view when the ground surface is viewed from above, and FIG. 7B shows a longitudinal sectional view for representing vibration transmission to the underground.

In the conventional technique described above, the oscillation plate 10 as an oscillator is placed in a direction orthogonal to the direction in which the plurality of geophones 12 as detectors are installed, and vibrates in the longitudinal direction. This is because when the vibration receiving device 12 vibrates in the direction in which the vibration receiving device 12 is installed, the resistance increases by the vibration receiving device 12, and a longitudinal wave directly affects the vibration receiving device 12 through the ground surface 14. This is because it is considered that the desired detection result is not obtained.
JP 2004-279064 A

  However, in the arrangement described above, although there is no influence of the longitudinal wave of the oscillator, it is affected by the transverse wave. In order to suppress the transverse wave transmitted on the ground surface in this way, the distance between the oscillator and the detector may be increased. However, the path of the reflected wave is also increased, making it difficult to detect the buried object.

  As a result of earnestly examining the above problems, the inventors of the present application have found that the longitudinal wave transmitted from the oscillator to the ground surface does not reach far beyond the expected range and dissipates while diffusing, and fundamentally changes the conventional arrangement. The present invention has been completed by successfully identifying the buried object.

  The present invention has been made in view of the above-mentioned problems of conventional buried object exploration, and an object of the present invention is to provide an oscillator in a reflection method exploration that can easily find a buried object in the underground from the ground surface. It is an object to provide a reflection method exploration system capable of specifying a buried object with high accuracy and clarity by devising the arrangement of the object.

  In order to solve the above-described problems, according to one aspect of the present invention, there is provided a reflection method exploration system for exploring buried objects and strata structures in the underground using a reflection method. An oscillator that generates vibration (transverse wave) in the transverse direction to the inside, a detector that detects a reflected wave that reaches the ground surface by being reflected at the buried object or formation boundary in the ground, and a buried object or And a position estimation device for estimating the position of the formation boundary, wherein the detector is disposed at a position not affected by the transverse wave transmitted from the oscillator through the ground surface. The

  It is assumed that the position is not affected by the transverse wave and is affected by the longitudinal wave. However, longitudinal waves are attenuated (dissipated) during transmission through the ground surface and do not substantially affect the detector. Therefore, this position, which has been conventionally avoided, becomes a favorable measurement position, and only the reflected wave at the buried object or the stratum boundary can be extracted with high accuracy and without being affected by the surface wave.

  Conventionally, in order to avoid the influence of the transverse wave, the distance between the oscillator and the detector has been increased. However, in the above arrangement, the influence of the longitudinal wave is small, so that the distance can be significantly shortened.

  The detector may be disposed within 45 degrees with respect to the vibration direction of the oscillator with the oscillator as the center, or may be disposed on a substantially extended line of the vibration direction of the oscillator.

  As described above, the longitudinal wave transmitted from the oscillator to the ground surface is dissipated, but the influence of the transverse wave is large. Therefore, the closer to the extension line of the oscillation direction of the oscillator, the smaller the influence of the transverse wave, so the influence of the overall surface wave is reduced, and only the reflected wave of the buried object can be extracted with high accuracy and clarity. Become.

  In order to solve the above problems, according to another aspect of the present invention, a reflection method exploration system for exploring buried objects and strata structures in the underground using a reflection method, which is installed on the ground surface, An oscillator that generates vibration (transverse waves) in the lateral direction with respect to the ground, a detector that detects the reflected waves that reach the surface of the earth after being reflected by the buried objects or the stratum structure, and the buried objects by the detected reflected waves Alternatively, there is provided a reflection method exploration system comprising: a position estimation device that estimates a position of a geological structure; and a vibration buffer material that is disposed between an oscillator and a detector and absorbs vibration of the oscillator. .

  Although this arrangement increases the effort for preparing and arranging the vibration buffer material, it is possible to minimize the influence of the surface wave of the oscillator in the detector, and only the reflected wave of the buried object can be extracted with high accuracy and clarity. It becomes possible.

  In order to solve the above problems, according to another aspect of the present invention, a reflection method exploration system for exploring buried objects and strata structures in the underground using a reflection method, which is installed on the ground surface, An oscillator that generates vibration (transverse waves) in the lateral direction with respect to the ground, a detector that detects the reflected waves that reach the surface of the earth after being reflected by the buried objects or the stratum structure, and the buried objects by the detected reflected waves Alternatively, a position estimation device for estimating the position of the stratum structure is provided, and a vibration cutting groove that cuts off the continuity of the medium (ground) to which vibration is transmitted is formed between the oscillator and the detector. A reflection probing system is provided.

  Although this arrangement increases the effort to prepare the vibration cutting groove, it is possible to minimize the influence of the surface wave of the oscillator in the detector, and it is possible to extract only the reflected wave of the buried object with high accuracy and clarity. Become.

  The oscillator may be composed of a magnetostrictive element. Here, the magnetostrictive element is applied to reflection method exploration in which a buried object at a depth of 0 to 100 m can be easily explored from the ground surface. A magnetostrictive element can vibrate with high energy and has a long stroke as compared with a sound wave or a piezoelectric element. Therefore, the position of the buried object can be reliably estimated even on soft ground or unsaturated ground.

  Further, the magnetostrictive element can be vibrated at a higher frequency than that of seismic waves or the like. High-frequency elastic waves (especially transverse waves) not only have high resolution, but also have high directivity, so that they are less diffused. Therefore, even when the buried object is small, the position can be specified with high accuracy.

  In addition, unlike a sound wave or the like, an individual medium can be directly vibrated, so that a longitudinal wave and a transverse wave can be freely switched by changing the installation state.

  A plurality of magnetostrictive elements may be provided and placed so that their longitudinal directions are substantially parallel. As described above, the detector of the present invention is arranged in the vibration direction of the oscillator. Therefore, when an attempt is made to add a magnetostrictive element in the longitudinal direction of the oscillator, the distance between the oscillator and the detector is shortened and the influence of the surface wave is increased. With such a configuration in which the magnetostrictive elements are juxtaposed, an empty space in the short side direction of the oscillator can be effectively used, and the wiring can be simplified, so that the cost and the reliability can be improved.

  In the reflection method exploration system of the present invention, a buried object in the underground can be easily explored from the ground surface, and the buried object can be specified with high accuracy and clarity.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the reflection method exploration, the oscillation direction of the oscillator and the detector are generally in a positional relationship orthogonal to each other. This is because when the oscillator vibrates in the direction in which the detector is installed, the resistance increases by the detector, and the longitudinal wave directly affects the detector, and the desired detection result cannot be obtained. It was because it was thought.

  In this embodiment, the longitudinal wave transmitted from the oscillator to the ground surface does not reach far, but dissipates while diffusing, and by devising the positional relationship between the vibration direction of the oscillator and the detector, high accuracy and The purpose is to clearly identify buried objects.

  On the other hand, there is a trade-off relationship between vibration energy and frequency in reflection method exploration. For example, seismic waves having high energy such as vibrators, hammer hits, dynamite, and blasting by a shaker have a low frequency, and sound waves having a high frequency have a low energy. Therefore, in the reflection method exploration system, a high energy source and a high frequency source are properly used depending on the application. In the present embodiment, in addition to the above-described new arrangement configuration of the oscillation direction of the oscillator and the detector, a magnetostrictive element having a large amount of displacement is adopted as a vibration source, and high energy and high frequency can be achieved simultaneously. It is aimed.

(First embodiment)
FIG. 1 is a longitudinal sectional view for explaining each component of the reflection method exploration system 100 in the present embodiment. The reflection method exploration system 100 of FIG. 1 includes an oscillator 110, a detector 120, and a position estimation device 130. In the present embodiment, the position of the buried object or the stratum boundary is estimated, but in order to facilitate understanding, hereinafter, it is simply abbreviated as a buried object. Therefore, the place to be buried includes the stratum boundary in the stratum structure exploration.

  The oscillator 110 is composed of a magnetostrictive element 112, a ground surface contact portion 114, and a protective case 116. The oscillator 110 is installed on the ground surface to vibrate the magnetostrictive element 112. 140 (S wave) is generated.

  The present embodiment is also characterized in that the magnetostrictive element 112 having excellent vibration performance is applied to a reflection method exploration in which a buried object and a stratum structure in a depth of 0 to 100 m can be easily explored from the ground surface. The magnetostrictive element 112 is a material that converts a voltage change into a volume change in one direction using a phenomenon that causes deformation according to the magnitude of the ferromagnetic material that constitutes the magnetostrictive element 112. Among them, the giant magnetostrictive material used in the present embodiment has characteristics that the displacement rate is large and the response speed is fast.

  The magnetostrictive element 112 can vibrate with higher energy than a sound wave or piezoelectric element used for reflection method exploration, and its stroke 142 (about 0.1 mm) is 10 to 50 times or more that of the piezoelectric element. . Therefore, even if the target ground is soft ground or unsaturated ground, the vibration energy can be reliably transmitted to the buried object 144, and the preliminary investigation on the possibility of underground exploration becomes unnecessary.

  The magnetostrictive element 112 is not limited to a high energy output, and the vibration frequency thereof can be arbitrarily set, and can vibrate at a higher frequency than that of the seismic wave. As such a magnetostrictive element, for example, when “V2Xπ20 (product name)” manufactured by TDK Corporation is used, a vibration frequency of 50 Hz to 20 kHz can be obtained.

  In general, when the vibration frequency is low, elastic waves are transmitted through a buried object for exploration, and a reflected wave cannot be obtained. Further, when the vibration frequency is high, the elastic wave is attenuated and does not reach the embedded object, and even if it reaches the embedded object, the reflected wave is also attenuated, so that it is difficult to obtain a good measurement result.

  In the reflection method exploration system 100, the higher the frequency, the higher the accuracy and the smaller the buried object can be detected. Here, since the high-frequency transverse wave output from the oscillator 110 has high directivity and low diffusion, it is particularly suitable for exploring a shallow buried object 144. However, when the frequency is high, the wavelength is shortened and the arrival rate of the elastic wave is deteriorated, so that the measurable range is narrowed. Therefore, the frequency should be determined in consideration of the measurement depth.

  Further, since the vibration frequency of the magnetostrictive element 112 can be arbitrarily changed, the position estimation device 130 described later sweeps the frequency of the oscillator 110 and selects the optimum (high sensitivity) frequency to estimate the position. Can do. For example, when the ground becomes soft, the waveform transmission speed v decreases, and the wavelength λ decreases even at the same frequency. At this time, based on the wavelength λ = v / f, the vibration frequency f (Hz) is changed in accordance with the change of the waveform transmission speed v, so that it is optimum even for soft ground or unsaturated ground with a low waveform transmission speed v. It is possible to maintain a large wavelength λ. Therefore, a highly accurate and stable measurement result can be obtained.

  The ground surface contact portion 114 is in surface contact with the ground surface while fixing and supporting the end portion of the magnetostrictive element 112 described above. Here, the contact area is increased by laying the oscillator 110 itself in the ground and filling the lower part.

  FIG. 2 is an explanatory diagram for explaining a structure for fixing the magnetostrictive element 112 to the ground surface contact portion 114. The expansion and contraction of the magnetostrictive element 112 is limited simply by installing the magnetostrictive element 112 on the inner surface of the ground surface contact portion 114, and the vibration is not sufficiently transmitted to the ground surface contact portion 114. As shown in FIG. 2, the vibration of the magnetostrictive element 112 can be efficiently transmitted to the ground surface contact portion 114 by fixing the end of the magnetostrictive element 112 to the surface 114b perpendicular to the main surface 114a of the ground surface contact portion 114. it can.

  The contact area of the ground surface contact portion 114 with the ground surface may be set based on the size and depth of the buried object (or the stratum boundary), the size, the number, the amplitude, and the frequency of the magnetostrictive oscillator. In addition, since the directivity of elastic wave transmission can be adjusted according to the size of the contact area, the contact area is set based on the size and depth of the buried object, and high-precision underground exploration according to the object Is possible. In the soft ground, which is one of the objects of this embodiment, elastic waves are easily attenuated, so it is particularly important to increase directivity.

  When it is desired to increase the vibration energy while keeping the contact area of the ground surface contact portion 114 with the ground surface constant, a large element can be used as the magnetostrictive element 112, but a plurality of parallel arrangements can also be used. In this case, the plurality of magnetostrictive elements 112 are arranged accurately in parallel with the same polarity, and signals having the same phase are applied. As described above, when the magnetostrictive element 112 is added in the longitudinal direction of the oscillator 110, the distance between the oscillator 110 and the detector 120 is shortened and the influence of the surface wave is increased. Such a configuration in which the magnetostrictive elements 112 are juxtaposed can effectively utilize an empty space in the short side direction of the oscillator, and can simplify the wiring, thereby reducing costs and improving reliability.

  The protective case 116 is configured in various shapes such as a rectangular shape and a flat plate shape in addition to the cylindrical shape shown in FIG. 2, and includes and protects the magnetostrictive element 112. At this time, the ground surface contact portion 114 also forms a part of the protective case 116. With this configuration, the portability and storage of the oscillator 110 can be improved, and the magnetostrictive element 112 can be waterproofed and dustproof. Therefore, the reflection method exploration system 100 can be operated even in some adverse environments such as rain. Can do.

  The detector 120 detects the reflected wave 146 that has been reflected by the underground buried object 144 (or the stratum boundary) and reached the ground surface.

  The position estimation device 130 is composed of a computer including a central processing unit (CPU), and estimates the position of the buried object 144 (or the formation boundary) based on the detected reflected wave 146.

  Moreover, the position estimation apparatus 130 can perform the search of the buried object (or the formation boundary) by the reflection method search system 100 a plurality of times under the same conditions, and can estimate the position from the average value of the plurality of measurements. Although a desired measurement signal and noise are mixed in one measurement, the measurement signal has repeatability, and noise has no repeatability. Therefore, by superimposing and averaging a plurality of measurements, noise can be canceled and the signal can be amplified, and only the measurement signal can be extracted accurately.

  Next, a specific exploration method using the reflection method exploration system 100 described above will be described.

  FIG. 3 is an explanatory view showing an installation example of the reflection method exploration system 100. 3A shows a plan view when the ground surface is viewed from above, and FIG. 3B shows a longitudinal sectional view for representing vibration transmission to the underground.

  The magnetostrictive element 112 according to the present embodiment can directly vibrate an individual medium unlike a sound wave or the like. Therefore, the installation state of the oscillator 110 can be changed to vertical or horizontal to freely switch between vertical and horizontal waves. it can. Therefore, both longitudinal waves (P waves) and transverse waves (S waves) can be used.

  However, the longitudinal wave is also referred to as a sparse / dense wave, and has a high transmission speed but is poor in directivity and tends to diffuse at a wide angle from the vibration source and is easily dissipated. Compared with the longitudinal wave, the transverse wave has high directivity and is difficult to dissipate, so that the vibration easily reaches the buried object, and a stable measurement result can be obtained. Moreover, since directivity can be maintained even if the frequency is increased, underground exploration can be performed on the kHz order. Therefore, in this embodiment, the oscillator 110 is installed or embedded horizontally to generate a transverse wave parallel to the ground.

  Moreover, in the plan view of FIG. 3A, two installation examples for generating a transverse wave are shown. Conventionally, as shown by the dotted line in FIG. 3A, the oscillator 110 is installed in a direction orthogonal to the direction in which the detector 120 is installed, and vibrates in the longitudinal direction thereof. However, by repeating the experiment, a better experimental result can be obtained when the oscillator 110 is directed away from the conventional device, that is, toward the detector 120 as shown by the solid line in FIG. I understood.

  When this phenomenon is examined in detail, the longitudinal wave transmitted through the ground surface, which was thought to directly affect the detector 120, is attenuated (dissipated) during transmission, and the detector 120 is substantially affected. It turned out not to give. Therefore, the buried object 144 can be detected with higher accuracy by directing the direction of the oscillator 110 toward the detector 120.

  Conventionally, in order to avoid the influence of the transverse wave, the distance between the oscillator 110 and the detector 120 is large. However, in the arrangement in which the oscillator 110 is directed to the detector 120, the influence of the longitudinal wave is low. The distance can be shortened significantly. For example, in the reflection method exploration system 100 of the present embodiment, good test results could be obtained even when the oscillator 110 and the detector 120 were brought closer to each other by about 50 cm. Below, the measurement result regarding three installation of the oscillator 110 mentioned above is compared.

  Here, the detector 120 is arranged on a substantially extended line in the vibration direction of the oscillator 110. However, the detector 120 is not limited to this range, and is not affected by the transverse wave of the oscillator 110, preferably as shown in FIG. As described above, the oscillator 110 may be disposed within 45 ° with respect to the vibration direction of the oscillator 110.

  As described above, the longitudinal wave transmitted from the oscillator 110 to the ground surface is dissipated, but the influence of the transverse wave is large. Therefore, the closer to the extension line of the oscillation direction of the oscillator, the smaller the influence of the transverse wave, so the influence of the overall surface wave is reduced, and only the reflected wave of the buried object can be extracted with high accuracy and clarity. Become.

  FIG. 4 is a diagram illustrating a measurement result of the embedded object 144 according to the installation state of the oscillator 110. FIG. 4A shows an exploration result when installing in the direction orthogonal to the detector 120 and applying a transverse wave, and FIG. 4B shows an exploration result when installing in the direction of the detector and applying a transverse wave. ing. The target buried object is assumed to have a depth of about 3 m.

  In Fig. 4 (a), there is a point 202 that seems to be a buried pipe, and if you know the existence of the buried object, you may be able to identify the buried object to some extent, but the energy of the transverse wave transmitted through the ground surface is too strong and measured. The result was buried in the surface wave 200. Compared with such a case, in FIG. 4B, surface waves are hardly detected, and the buried pipe 210 provided in the shallow portion in the ground and the tank bottom plate provided in the deep portion 212 are clearly detected. From this result, it is possible to understand the high accuracy when installed in the direction of the detector 120.

  Here, the reason why the detectors 120 are symmetrically arranged on both sides of the oscillator 110 is that if they are biased to one side, the reflection path becomes long and the detection accuracy decreases, and the detectors 120 are arranged close to both sides. By doing so, the reflected wave can be detected efficiently.

  Further, in actual reflection method exploration, the oscillator 110 is installed at a plurality of locations, and a plurality of detection signals of the detector 120 are acquired for each. Therefore, all the combinations are changed by the moving means while maintaining the positional relationship between the oscillator 110 and the detector 120.

  In the reflection method exploration system 100 as described above, the buried object in the underground can be easily explored from the ground surface with high vibration energy and high frequency. Therefore, it is possible to reliably extract the buried object under the optimum conditions regardless of the ground state to be measured.

(Second Embodiment)
In the first embodiment, the optimal arrangement of detectors has been described using the characteristics of longitudinal waves that travel on the ground surface. However, in the second embodiment, surface waves that transmit such a ground surface are forced. A configuration for damping is described below.

  FIG. 5 is an explanatory diagram showing another installation example of the reflection method exploration system 100. FIG. 5A shows a plan view when the ground surface is viewed from above, and FIG. 5B shows a longitudinal sectional view for representing vibration transmission to the underground. Here, a vibration buffer material 160 is disposed between the oscillator 110 and the detector 120, and the vibration buffer material 160 absorbs the vibration of the surface wave 162 of the oscillator 110.

  Although this arrangement increases the effort for preparing and arranging the vibration damping material 160, the influence of the surface wave 162 of the oscillator 110 on the detector 120 can be minimized, and only the reflected wave of the embedded object 144 can be accurately and clearly defined. Can be extracted.

(Third embodiment)
In the third embodiment, another configuration for forcibly attenuating a surface wave transmitted on the ground surface will be described instead of the vibration damping material 160.

  FIG. 6 is an explanatory view showing still another installation example of the reflection method exploration system 100. 6A shows a plan view when the ground surface is viewed from above, and FIG. 6B shows a longitudinal sectional view for representing vibration transmission to the underground. Here, a vibration cutting groove 170 is formed between the oscillator 110 and the detector 120, and the transmission of the vibration of the surface wave 172 is cut off.

  With this configuration, as in the second embodiment, although the effort for preparing the vibration cutting groove 170 is increased, the influence of the surface wave 172 of the oscillator 110 in the detector 120 can be minimized, and only the reflected wave of the buried object can be obtained. It becomes possible to extract with high accuracy and clarity.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  INDUSTRIAL APPLICABILITY The present invention can be used for a reflection method exploration system for exploring buried objects and strata structures in the underground using a reflection method.

It is a longitudinal cross-sectional view for demonstrating each component of a reflection method exploration system. It is explanatory drawing for demonstrating the fixation structure to the ground surface contact part of a magnetostriction element. It is explanatory drawing which showed the example of installation of the reflection method search system. It is the figure which showed the measurement result of the buried object by the installation state of an oscillator. It is explanatory drawing which showed the other example of installation of the reflection method search system. It is explanatory drawing which showed the other example of installation of the reflection method search system. It is the layout which showed the example of the conventional arrangement | positioning of each component in the conventional reflection method search.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Reflection method exploration system 110 ... Oscillator 112 ... Magnetostrictive element 114 ... Ground surface contact part 116 ... Protective case 120 ... Detector 130 ... Position estimation apparatus 160 ... Vibration damping material 170 ... Vibration cutting groove

Claims (7)

A reflection method exploration system for exploring buried objects and formations in the underground using a reflection method,
An oscillator that is installed on the ground surface and generates transverse vibration (transverse wave) to the ground;
A detector that detects a reflected wave that reaches the surface of the earth by reflecting at the buried object or formation boundary in the ground;
A position estimation device that estimates the position of the buried object or the boundary of the formation by the detected reflected wave;
With
The detector is disposed at a position that is not affected by a transverse wave transmitted from the oscillator through the ground surface.   2. The reflection survey system according to claim 1, wherein the detector is disposed within 45 degrees with respect to a vibration direction of the oscillator around the oscillator.   The reflection detector system according to claim 2, wherein the detector is disposed on a substantially extended line in a vibration direction of the oscillator. A reflection method exploration system for exploring buried objects and formations in the underground using a reflection method,
An oscillator that is installed on the ground surface and generates transverse vibration (transverse wave) to the ground;
A detector that detects a reflected wave that reaches the surface of the earth by being reflected by the underground buried object or the stratum structure;
A position estimation device for estimating the position of the buried object or the geological structure from the detected reflected wave;
A vibration buffer disposed between the oscillator and the detector and absorbing vibration of the oscillator;
A reflection survey system characterized by comprising: A reflection method exploration system for exploring buried objects and formations in the underground using a reflection method,
An oscillator that is installed on the ground surface and generates transverse vibration (transverse wave) to the ground;
A detector that detects a reflected wave that reaches the surface of the earth by being reflected by the underground buried object or the stratum structure;
A position estimation device for estimating the position of the buried object or the geological structure from the detected reflected wave;
With
A reflection method exploration system characterized in that a vibration cutting groove is formed between the oscillator and the detector to cut off the continuity of the medium through which vibration is transmitted.   The reflection method exploration system according to claim 1, wherein the oscillator includes a magnetostrictive element.   The reflection method exploration system according to claim 6, wherein a plurality of the magnetostrictive elements are provided and are placed so that their longitudinal directions are substantially parallel to each other.

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