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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.

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.