Application of Qualitative and Quantitative Analyses ofSelf-Potential Anomaly in Caves Detection in DjuandaForest Park, Bandung

摘要

Self-Potential (SP) is naturally occurring electric potential difference observed at the surface. In the vicinity of a cave, SP anomaly is dominantly generated by the resistivity contrast of the cave with its environment and the current source associated with the streaming potential generated by fluid flow through the cave. In this study we applied a simple qualitative analysis to understand the SP values caused by streaming potential and values that are due to the presence of caves. Further, we conducted two-dimensional SP continuous modeling by solving the fluid velocity vector first in the modeling domain. Current source distribution and hence the SP value are obtained by incorporating resistivity value of the subsurface and calculating the divergence of the velocity vector. For validation, this scheme was applied in detection caves dug by Japanese army during WWII as at Djuanda Forest Park, Bandung. The results can be used to understand the characteristics of fluid flow and current source distribution around cavities that are responsible for the observed SP anomaly at the surface.