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The Space Environment Research Center of the Kyushu University (SERC) is developing a magnetometer which is one of the mission instrument of the Kyushu Satellite (QSAT). We must understand residual magnetism around the magnetometer in order to correctly measure the magnetic field in space. In fact, the QSAT bus system may have considerable residual magnetism. There is a possibility that this residual magnetism will have a bad effect on the mission, so we have to measure it and estimate how much effect it will have on the mission magnetometer. For the reasons stated above, we have developed a measurement system for residual magnetism of all satellite’s bus units semi-automatically. This system uses the UGF-3 magnetometer. Thanks to this instrument, it is possible to estimate residual magnetism of QSAT bus units precisely even in a regular laboratory. This system can estimate residual magnetism of a sample, if its moment is larger than 0.0001 [Am 2 ]. Also, the result possesses higher reliability, if the magnetic moment is larger than 0.01 [Am 2 ]. We completed measuring eight units’ residual magnetism, and we analyzed how much magnetic interference would be caused to the mission magnetometer. The results are much less than permissible levels, so magnetic interference is not a critical problem in our view.

An integrated geophysical survey was carried out in a new dwelling area at 15-May town, southeast Cairo, Egypt. The buildings in this area are intensively affected by dangerous cracks that cause structural instability. The survey aimed to image the shallow subsurface structures, including karstic features, and evaluate their extent, as they may cause rock instability and lead to cracking of the residential buildings. Resistivity profiling (2-D), using a dipole-dipole array and ground penetrating radar (GPR) surveys were carried out along seven parallel traverses extending about [Formula: see text] between the buildings blocks. Additional measurements using a Schlumbereger array and very low frequency electromagnetic (VLF-EM) methods were conducted. The acquired data were processed and interpreted integrally to elucidate the shallow structural setting of the site. Integrated interpretation led to the delineation of hazard zones rich with karstic features in the area. Most of these karstic features are associated with vertical and sub-vertical linear features such as faults, fracture zones, and geologic contacts. These features are the main reason of the rock instability that resulted in potentially dangerous cracking of residential buildings.

Recent development of marine magnetic gradient systems, using arrays of sensors, has made it possible to survey large contaminated areas very quickly. However, underwater Unexploded Ordnances (UXO) can be moved by water currents. Because of this mobility, the cleanup process in such situations becomes dynamic rather than static. This implies that detection should occur in near real-time for successful remediation. Therefore, there is a need for a fast interpretation method to rapidly detect signatures of underwater objects in marine magnetic data. In this paper, we present a fast method for location and characterization of underwater UXOs. The approach utilises gradient interpretation techniques (analytic signal and Euler methods) to locate the objects precisely. Then, using an iterative linear least-squares technique, we obtain the magnetization characteristics of the sources. The approach was applied to a theoretical marine magnetic anomaly, with random errors, over a known source. We demonstrate the practical utility of the method using marine magnetic gradient data from Japan.

This paper presents an enhancement of the local-wavenumber method (named ELW for “enhanced local wavenumber”) for interpretation of profile magnetic data. This method uses the traditional and phase-rotated local wavenumbers to produce a linear equation as a function of the model parameters. The equation can be solved to determine the horizontal location and depth of a 2D magnetic body without specifying a priori information about the nature of the sources. Using the obtained source-location parameters, the nature of the source can then be inferred. The method was tested using theoretical simulations with random noise over a dike body. It was able to provide both the location and an index characterizing the nature of the source body. The practical utility of the method is demonstrated using field examples over dikelike bodies from Canada and Egypt.

The archaeology and history of Okinawa are receiving a great deal of public attention as the Okinawans attempt to define their cultural and political identity in the closing decade of the 20th century. In an attempt to explore some of the old ruins in the area of Futenma, an integrated geophysical survey had been conducted in the form of two and three dimensional geoelectrical resistivity, surface seismic wave and seismic reflection surveys. The interpretation results of geoelectric survey had identified three-layer structure, which consists of superficial low-resistivity layer that indicates filling of Shimajiri maaji followed by high-resistivity layer that indicates Ryukyu limestone, and low-resistivity layer that indicates Shimajiri mudstone group. Also clear-cut reflectors of seismic reflection lines with good continuity are identified. These reflectors considered to reveal the surface of Ryukyu limestone of archaeological remains. The result of the surface wave survey identified two-layer structure that consists of superficial layer of surface wave velocity (0.3 km/s) overlies a relatively high velocity layer (0.5 km/s). The low velocity layer is estimated to indicate filling of Shimajiri maaji, while the high velocity layer correlates Ryukyu limestone formation.From the results it was predicted that subsurface structures of ruins influence the result of exploration even if their sizes are not large. Therefore, characteristic patterns due to a certain ruin structure can be distinguished, by making comparison with the excavation findings. The soil covering Ryukyu limestone is relatively thin; however, ruin structures naturally exist in the sedimentation soil above the limestone. It is highly probable that, as we trace back to older time, the land surface would be closer in shape to the upper surface of Ryukyu limestone. Furthermore, the survey results showed that Ryukyu limestone itself is considered to be divided into fresh zone and weathered zone, which possibly has been erroded and is providing channels for the ground water flow including a doline.According to the results we obtained in this work, even though, geoelectrical resistivity technique is stand-alone for archaeological prospection, its integration with seismic methods, mainly Surface seismic wave, survey give successful results.

Esh El-Mallaha area has a great importance due to its location on the western flank of the Gulf of Suez, Egypt. Areas around the Gulf of Suez represent potential prospects for hydrocarbon resources. However, seismic exploration in the area has had a little success in locating hydrocarbon resources. The main exploration problem is the basement complex structure characterizing the study area. In this study, we attempt to image the subsurface structure of the area using interpretation of magnetic data based on Euler method. We have applied Euler method to the total.

We investigate the analytic signal method and its applicability in obtaining source locations of compact environmental magnetic objects. Previous investigations have shown that, for two-dimensional magnetic sources, the shape and location of the maxima of the amplitude of the analytic signal (AAS) are independent of the magnetization direction. In this study, we show that the shape of the AAS over magnetic dipole or sphere source is dependent on the direction of magnetization and, consequently, the maxima of the AAS are not always located directly over the dipolar sources. Maximum shift in the horizontal location is obtained for magnetic inclination of 30°. The shifts of the maxima are a function of the source-to-observation distance and they can be up to 30% of the distance. We also present a method of estimating the depths of compact magnetic objects based on the ratio of the AAS of the magnetic anomaly to the AAS of the vertical gradient of the magnetic anomaly. The estimated depths are independent of the magnetization direction. With the help of magnetic anomalies over environmental targets of buried steel drums, we show that the depths can be reliably estimated in most cases. Therefore, the analytic signal approach can be useful in estimating source locations of compact magnetic objects. However, horizontal locations of the targets derived from the maximum values of the AAS must be verified using other techniques.

We have developed a simple approach to determine the depth and radius of subsurface cavities from the microgravity data. Horizontal location of cavity center is picked up by an algorithm as the projection of the minimum of gravity anomaly. Depth to the cavity center is determined using back propagation neural network. The cavity radius can be then calculated using the determined parameters if the density contrast between the host rock and the cavity filling materials is known or assumed according to the geological background. The present method is tested by several synthetic data sets and showed high ability to determine the cavity parameters in presence of natural noise. Applying the method to field data from Medford cavity site, Florida, the estimated cavity parameters are coincident the boring results. The method is proved to be fast and robust and can be used in field situation.

The inversion of geoelectrical resistivity data is a difficult task due to its non-linear nature. In this work, the neural network (NN) approach is studied to solve both 1D and 2D resistivity inverse problems. The efficiency of a widespread, supervised training network, the back-propagation technique and its applicability to the resistivity problem, is investigated. Several NN paradigms have been tried on a basis of trial-and-error for two types of data set. In the 1D problem, the batch back-propagation paradigm was efficient while another paradigm, called resilient propagation, was used in the 2D problem. The network was trained with synthetic examples and tested on another set of synthetic data as well as on the field data. The neural network gave a result highly correlated with that of conventional serial algorithms. It proved to be a fast, accurate and objective method for depth and resistivity estimation of both 1D and 2D DC resistivity data. The main advantage of using NN for resistivity inversion is that once the network has been trained it can perform the inversion of any vertical electrical sounding data set very rapidly.

Recent developments in airborne magnetic detection systems have made it possible to detect small ferro-metallic objects. However, airborne magnetic data can be really large and, therefore, there is an increasing need for a fully automatic interpretation technique that could be used to make decisions regarding the nature of the sources in the field in real time. The massively parallel processing advantage of artificial neural networks makes them suitable for hardware implementations; therefore, using these networks in conjunction with a magnetic system has the potential to greatly speed up the detection of ferro-metallic objects. In this paper, we have developed a new method for detection and characterization of unexploded ordnance (UXO) using a Hopfield neural network as applied to airborne magnetic data. The Hopfield network is used to optimize the magnetic moment of a dipole source representing the magnetic object at regular locations. For each location, the Hopfield network reaches its stable energy state. The location of the object corresponds to the location yielding the minimum Hopfield energy. Output results include position in two dimensions (horizontal location and depth), magnetic moment, and effective inclination. Theoretical and actual field examples show that the Hopfield network is accurate and objective tool for the detection of UXO. Moreover, because the Hopfield neural network is a natural analog-to-digital converter, it is ideally suited for incorporation into airborne magnetic instrumentation systems.

The interpretation of actual geophysical field data still has a problem for obtaining a unique solution. In order to investigate the groundwater potentials in Saqqara archaeological area, vertical electrical soundings with Schlumberger array have been carried out. In the interpretation of VES data, 1D resistivity inversion has been performed based on a horizontally layered earth model by El-Qady (1995). However, some results of 1D inversion are not fully satisfied for actual 3D structures such as archaeological tombs. Therefore, we have carried out 2D inversion based on ABIC least squares method for Schlumberger VES data obtained in Saqqara area. Although the results of 2D cross sections were correlated with the previous interpretation, the 2D inversion still shows a rough spatial resistivity distribution, which is the abrupt change in resistivity between two neighboring blocks of the computed region. It is concluded that 3D interpretation is recommended for visualizing ground water distribution with depth in the Saqqara area.

Drilling engineering education in universities has historically been closely tied to the oil and gas industries and based on a one-industry discipline.The professors have taught courses and specialized skills that would satisfy the demand from drilling experts. However, drilling engineers of the future must be educated to have skills to solve problems and to develop new technologies with a good knowledge of mathematics, computer programming, geoscience, management, etc.Drilling engineers must learn the following abilities in ten years after being hired by oil companies: (1) Fundamental knowledge and technical skills related to drilling operation; (2) Problem solving skills by experiments and data analysis; (3) Techniques of numericel modeling and analysis; (4) Risk analysis, petroleum economics, and basic knowledge of related areas like geology, exploration geophysics, logging, reservoir engineering, production engineering; (5) Data management and business skills; and (6) Teamwork and cultural awareness. To educate these abilities, university and company education have their own responsibility.This paper describes the state of the art and the problems of petroleum engineering education in five Japanese universities: University of Tokyo, Waseda University, Kyushu University, Tohoku University and Akita University. The academic program and system in these universities are gradually changing to cope with the recent structural changes in Japanese industry. The percentage of students continuing graduate education is steadily rising, while very few students find employment in petroleum industry. To improve the quality and value of petroleum engineering education, the universities need technical and financial support by private companies and government organization.

An advanced geoelectrical technique for imaging potential fractures has been developed by Engineering Geophysics Laboratory of Kyushu University. The method, fluid‐flow tomography (FFT), has been applied to monitor fluid‐flow behaviors during massive water/steam injection operations through a borehole. Fluid‐flow behaviors in potential fractures could be continuously traced and visualized as a function of time by the FFT system. Potential fractures can be evaluated by 3-D inversion of self‐potential (SP) anomalies based on a potential theory similar to the hypocenter of the earthquakes. The FFT method has been applied to determine the location of fractures in a geothermal area in Japan.

Mine clearing is an urgent matter to be tackled internationally not only from the humanitarian point of view but also from the viewpoint of reconstruction and economic growth in the area where a cessation of armed conflicts was achieved. Operations are already underway to clear landmines, but currently they rely heavily on human works due to a lack of safer and efficient demining techniques. Various geophysical exploration techniques have been applied to the problem of detecting and mapping underground mines and UXO with practical success. The most productive techniques are magnetic, electromagnetic and Ground Penetrating Radar methods for which the mine target exhibits the greatest physical contrast with the host geological formation. Developments of more sensitive geophysical equipments for detecting mines is required to meet the geophysical conditions of lower contrast with the environment and at the scale of the target. Starting from May 2004, a channel of communication between the Egyptian embassy in Tokyo and the Kyushu University Mine Action Group (QMAG) team on the topics of landmines in Egypt has been established on how to apply geophysical techniques newly developed geophysical techniques in Japan to solve the problem of landmines in Egypt. We arranged a campaign for landmines detection technology in Egypt, conducted by research teams of QMAG of Kyushu University. During the campaign three geophysical techniques, DC resistivity, H207agnetic and ground penetration radar were tested and evaluated.

Several geophysical exploration methods have been applied to the problem of detecting and mapping underground archaeological remains with practical success. The most productive techniques are those for which the archaeological target exhibits the great physical contrast with the surrounding formation. Most widely used in archaeological prospection include Magnetic, Electromagnetic, Ground Penetrating Radar and Electrical Resistivity methods applied at the shallow surface. However, these conventional geophysical measurements for an archaeological prospection has been tried with relatively limited success. Therefore, we have developed an automatic imaging system named as Handy-ARM (Archaeological Resistivity Meter) for an archaeologist based on electrical resistivity techniques.

P058 ABSTRACT DETECTION OF WEAK ZONES BY INVERSION OF 2- D ELECTRICAL IMAGING DATA USING NEURAL NETWORK HO TRONG LONG GAD EL-QADY KEISUKE USHIJIMA Department of Earth Resources Engineering Graduate School of Engineering Kyushu University Hakozaki 6-10-1 Higashi-ku Fukuoka 812-8581 Japan There is increasing interest particularly for environmental and engineering studies of nearsurface areas. Electrical Imaging or electrical tomography is a survey technique developed for the investigation of areas of complex geology where the use of resistivity sounding and other techniques is unsuitable. Inversion techniques of Electrical Imaging data normally done using least-squares method (e.g. Sasaki 1989 1992 Loke et

Buried landmines pose serious hazard in more than 60 countries across the globe. Recent estimations suggest as many as 110 million such objects lay worldwide. Detecting these mines with standard metal detectors is difficult, as many are comprised primarily of plastic, with often only a firing pin as the sole metallic component. The development of geophysical methods for unexploded Ordnance (UXO) detection has been underway for almost ten years, and arose in the international context from the need to rapidly characterizing large areas of potentially UXO-contamination. In this work, the geoelectrical resistivity could be one of the most useful parameters to discriminate ordnance types, shapes and locations especially near the surface. This study represents a successful trial to adopt the geoelectrical resistivity technique for detecting buried UXO and other clutter environmental noise. A forward and inversion routine had been adopted and applied to synthetic resistivity models for different UXO and landmines. In addition, models of non metal ordnance had been used, and were successfully detected. The obtained results show high efficiency of the technique to image those models. Now we are trying to adopt the technique to work in the filed, hence apply it for test site.

Application of geophysical methods has increased to investigate near-surface horizons of interests in related to environmental and engineering geophysics because geophysical methods are cost-effective and large areas can be quickly surveyed at relatively low cost without borings and trench excavations. The most productive geophysical methods are Ground Penetrating Radar and Electrical Resistivity methods for which the target exhibits the greatest physical contrast with respect to the surrounding formations. However, the geoelectrical geophysics is very difficult to predict the sub-surface using conventional techniques because of the shortage of the resolution. These geophysical techniques have required upgrading of data acquisition accuracy of the methods using a multichannel resistivity tool such as Handy Archaeological Resistivity Meter developed by the joint research of Kyushu University and OYO Corporation in Japan. Geoelectrical methods have the economic advantages to solve various archaeological problems. However, there was no successful 3D computer program required for interpreting observed apparent resistivity data. In the present paper, a robust 3D computer program was developed and applied to archaeological prospection. Results of 3D inversion of VES data are compared with the results of GPR method and evaluated with archaeologists of Archaeological Society of Japan.

Summary We present a new method for interpretation of potentialfield anomaly data. A linear equation, involving the anomaly and its horizontal gradient, is derived to provide both the depth and nature of the buried sources. The proposed method is similar to the Euler technique; however, it uses a shape factor (q) instead of a structural index (η) to characterize the buried sources. The method is tested using theoretical simulations with different gravity and magnetic models placed at different depths with respect to the observation height. In all cases, the method adequately estimated the locations and the approximate shapes of the sources. Results from field examples will be discussed at the meeting.

P114 INTERPRETATION OF ISOLATED GRAVITY ANOMALIES USING EULER DECONVOLUTION 1 Abstract We have developed a simple approach to determine simultaneously the horizontal location depth and structural index of simple geometrical structures from isolated gravity anomalies based on Euler’s homogeneity equation. The horizontal location is determined using conventional Euler method applying approximated structural index value. Using the determined horizontal location parameters as constant values Euler’s equation can be written as a linear relation between the depth and the structural index for each observation point. Plotting this relation for a number of observation points produce a set of intersecting lines. The common

An advanced geophysical technique for reservoir monitoring by electrical prospecting has been developed by the joint research works of Kyushu University and JAPEX on the EOR Project in Canada. The method has been applied to monitor fluid-flow behaviors during steam injection operations. With an automatic recording system controlled by a personal computer, charged potentials and spontaneous potentials can be simultaneously measured as a function of time at multiple stations surrounding an operating borehole. Fluid-flow behavior in the subsurface was visualized as a function of time by means of contour maps of the residual potential and the relative changes of apparent resistivity during the thermally enhanced oil recovery process at Hangingstone test site in Fort McMurray, Alberta, Canada.

According to the “Sunshine Project”, various gee. physical survey have been conducted in many geotherma: areas in Japan, In this Project, geophysical data har been interpreted as layered earth structures. However! there are often inherent difficulties in determining layer thickness and resistivities from one geophysical method alone in difficult areas. In order to combat this problem, numerical modeling for 2D or 3D models are usually conducted and the observed data has been carefully checked in order to get the best fitted model in a geothermal area. In the present paper, procedures for interpretation of geophysical data are carefully checked with well log data and an optimum method for geothermal exploration are derived in difficult area from the success case history of Hatchobaru geothermal field ( 55 MW, unit II ) by KEPCO in Japan.

Exploration in the northern Red Sea of Egypt has had little success in locating hydrocarbon accumulation. The main exploration problems in this region are the complex block faulting and Miocene salt structures. The complex basement block structure arises from the different ages of faults and the difficulty of determining the exact age relations. In this paper, we present a case study of structural mapping using application of the Euler method to high-resolution aeromagnetic data collected in the Quseir area of the northern Red Sea of Egypt. The results indicated that the area is affected by sets of fault systems, which are mainly trending in the NNW-SSE, NW-SE and NE-SW directions. The results also delineated boundaries of a long and wide magnetic body on the offshore part of the study area. This basement intrusion is most probably related to the Red Sea rift and perhaps associated with structures higher up in the sedimentary section. As a result, the area above this anomaly is highly recommended for further oil exploration. This example illustrates that high-resolution aeromagnetic surveys can help greatly in delineating subsurface structure in the northern Red Sea of Egypt.