Geophysical Survey for Site Investigation at a New Dwelling Area, Egypt
Eslam A. Elawadi(1), Gad M. El-Qady(2), Ahmed A. Negm(3) and Keisuke Ushijima(1)
(1) Kyushu University, Japan. (2) National Research Institute of Astronomy and Geophysics, Egypt. (3) Nuclear Materials Authority, Egypt.
Contacts: eslam@mine.kyushu-u.ac.jp (Eslam A. Elawadi)
Abstract
A resistivity survey was conducted using the dipole-dipole array at a new dwelled area at 15-May city, southeast Cairo, Egypt. The buildings at this area are hardly damaged by serious cracks that affect its stability. The objective of this study is to investigate the near subsurface of the area and to locate any geologic structures that may be one of the cause of these cracks. The resistivity measurements were carried out along seven parallel profiles extending about 150 meters between the buildings blocks. In addition, geophysical measurements using GPR, VLF and VES techniques were conducted along some of these survey lines. Integrated interpretation of the acquired data through the use of 2-D inversion technique has greatly improved the geological understanding of the subsurface. It has revealed that the area is highly affected by linear features (faults, fractures, geologic contacts) trending in NW-SE direction. In the southern part of the area, where a new garden is established, the electrical response is dominated by anomalous low-resistivity zone. This is referred to the effect of the surface water used in irrigation of the garden's trees. Moreover, this water can be considered as a source of lubrication for the fracture systems in the area. A few kilometers to the south, limestone-mining operations, using dynamite explosions, is very active. These frequent explosions can generate minor distortion along the fracture system. These distortions can be considered as the main reason of the cracks appeared on the new buildings in the area.
raeg2003@tansa.kumst.kyoto-u.ac.jp
Last modified: Wed Oct 30 12:16:30 2002