Preliminary results of stress measurement using drill cores of TCDP Hole-A: An application of anelastic strain recovery method to three-dimensional in-situ stress determination

Weiren Lin, En-Chao Yeh, Hisao Ito, Tetsuro Hirono, Wonn Soh, Chien Ying Wang, Kuo Fang Ma, Jih Hao Hung, Sheng Rong Song

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

In order to understand the feature of rock stress change at different depths above, within, and beneath the Chelungpu fault after the Chi-Chi earthquake, we employed a core-based stress measurement method, anelastic strain recovery (ASR) technique to determine both the orientations and magnitudes of present three-dimensional principal rock stresses using drill core samples retrieved from Taiwan Chelungpu-fault Drilling Project (TCDP) main Hole-A. The core samples used were taken from three depths; and their lithology were sandstone at depths of 592 and 1755 m and siltstone at 1112 m. The anelastic strains of the specimens in nine directions, including six independent directions, were measured after its in-situ stress was released. Acquired anelastic strains were of high quality and reached several hundred microstrains, which is sufficiently high for the accuracy of the measurement system used. Thus, the strain data could be used for three-dimensional analysis resulting in the determination of orientations and the estimation of magnitudes of the principal in-situ stresses. Preliminary stress measurement results showed that the orientations of principal stresses changed between the shallower depth above the fault and the deeper depth beneath it, that is, the present stress distribution in the TCDP hole might be influenced by the Chelungpu fault rupture. At the same time, anelastic strain recovery measurement is well suited for the task of directly determining the orientations of principal in-situ stresses and to estimate the magnitude of stresses at large/great depth.

Original languageEnglish
Pages (from-to)379-393
Number of pages15
JournalTerrestrial, Atmospheric and Oceanic Sciences
Volume18
Issue number2
DOIs
Publication statusPublished - 2007 Jun 1

Keywords

  • Anelastic strain recovery
  • Chelungpu fault
  • Core-based method
  • Stress measurement
  • Taiwan Chelungpu-fault Drilling Project

ASJC Scopus subject areas

  • Oceanography
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)

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