Fault Zone Resistivity Structure and Monitoring at the Taiwan Chelungpu Drilling Project (TCDP)

• Main Authors: Chih-Wen Chiang, Martyn J. Unsworth, Chow-Son Chen, Chien-Chih Chen, Andrew Tien-Shun Lin, Han-Lun Hsu
• Format: Article
• Language: English
• Published: Chinese Geoscience Union 2008-01-01
• Series: Terrestrial, Atmospheric and Oceanic Sciences
• Subjects: Audio-magnetotelluric; TCDP; Chelungpu fault; Resistivity structure; Geo-electrical strike; Time variations
• Online Access: http://tao.cgu.org.tw/images/attachments/v195p473.pdf

The Taiwan Chelungpu-fault drilling project (TCDP) has undertaken scientific drilling and directly sampled the sub-surface rupture of the 1999 Chi-Chi earthquake. Audio-magnetotelluric (AMT) measurements were used to investigate electrical resistivity structure at the TCDP site from 2004 - 2006. These data show a geoelectric strike direction of N15°E to N30°E. Inversion and forward modeling of the AMT data were used to generate a 1-D resistivity model that has a prominent low resistivity zone (< 10 ohm-m) between depths of 1100 and 1500 m. When combined with porosity measurements, theAMT measurements imply that the ground water has a resistivity of 0.55 ohm-m at the depth of the fault zone.