HR: 0800h
AN: T51A-1328    [Abstracts]
TI: The Existence Of Duplex Structure Within Taiwan Chelungpu-Fault Drilling Project By Core Observation And Logging Data
AU: * Yeh, E
EM: yeh@jamstec.go.jp
AF: Kochi Institute for Core Sample Research, JAMSTEC, 2-15 Natsushima-cho, Yokosuka, 237-0061 Japan
AU: Lin, T
EM: andrewl@cc.ncu.edu.tw
AF: Dept. of Earth Sciences, National Central University, 300, Chungdai Rd., Chung-Li, 320 Taiwan
AU: Lin, W
EM: lin@jamstec.go.jp
AF: Kochi Institute for Core Sample Research, JAMSTEC, 2-15 Natsushima-cho, Yokosuka, 237-0061 Japan
AU: Hirono, T
EM: hirono@jamstec.go.jp
AF: Kochi Institute for Core Sample Research, JAMSTEC, 2-15 Natsushima-cho, Yokosuka, 237-0061 Japan
AU: Hung, J
EM: jhung@earth.ncu.edu.tw
AF: Dept. of Earth Sciences, National Central University, 300, Chungdai Rd., Chung-Li, 320 Taiwan
AU: Yue, L
EM: lyue@Princeton.EDU
AF: Dept of Geosciences, Princeton University, Guyot Hall, Washington Rd., Princeton, NJ 08544-1003 United States
AU: Soh, W
EM: soh@jamstec.go.jp
AF: Kochi Institute for Core Sample Research, JAMSTEC, 2-15 Natsushima-cho, Yokosuka, 237-0061 Japan
AU: Song, S
EM: srsong@ntu.edu.tw
AF: Dept. of Geosciences, National Taiwan University, P.O. Box 13-318, Taipei, 106 Taiwan
AB: Taiwan Chelungpu-fault Drilling Project (TCDP) had conducted continuous coring and logging in two holes 40m apart to investigate the rupture mechanism in the north segment of 1999 Taiwan Chi-Chi earthquake. Across two holes, three fault zones can be correlated by visual core description and logging interpretation, such as Fault Zone at 1111m depth of Hole-A (FZA1111) can be correlated to FZB1137, FZA1153 to FZB 1194, FZA1222 to FZB1243. All three fault zones have characters of reverse faulting. This observation triggered the issue of the duplex existence in the drill site. These fault zones are obviously identified on the core examination and observed at locations with the similar pattern of lithology column, regarding to the grain size and formation thickness. By logging interpretation, the special log character of a resistivity anomaly, a slow sonic anomaly and deformation image in Fullbore Formation Microimage (FMI) is detected around FZA1111-FZB1137, which is corresponded to a distinct fault core in the core examination. Two deeper fault zones have been identified in the core and FMI data but no obvious log anomaly can be observed around these depths. After restoring the faulting effect, the reconstructed lithology column is shown that the formations of hanging walls in the fault zones are the same. This result implied that a duplex structure existed. The implication is also supported by the logging data of Natural Gamma-Ray. The existence of a duplex is further consistent with the out-of-sequence characteristics of Chi-Chi rupture. Furthermore, it indicates that regional structures were developed upsection within the fault zone system.
DE: 7209 Earthquake dynamics (1242)
DE: 7221 Paleoseismology (8036)
DE: 8045 Role of fluids
DE: 8102 Continental contractional orogenic belts and inversion tectonics
DE: 8118 Dynamics and mechanics of faulting (8004)
SC: Tectonophysics [T]
MN: Fall Meeting 2005