In-situ stress at the northern portion of the Chelungpu fault, Taiwan, estimated on boring cores recovered from a 2-km-deep hole of TCDP
Resource
EARTH PLANETS AND SPACE,60,809-819.
Journal
Earth Planets and Space
Pages
809-819
Date Issued
2008
Date
2008
Author(s)
Abstract
Abstract We have investigated the depth variation in the stress state at the northern part of the Chelungpu fault, Taiwan, which slipped during the 1999 Chi-Chi earthquake ( M w 7.6). In-situ stress around the fault was estimated based on the stress memory of rocks recovered from five depths (739–1316 m) of a 2-km-deep-hole. The borehole intersects a fault zone at a depth of 1111 m (FZ1111), which is the best candidate for the Chelungpu fault. Our main results are: (1) the S Hmax direction is parallel to the slip for the Chi-Chi earthquake and agrees with those of the local, regional, or tectonic scales estimated from various stress indicators; (2) significant aspects of the stress field are identical to those of paleostress; (3) the horizontal differential stress was significantly reduced just above FZ1111, which may be attributable to the existence of a significantly deformable zone at this depth.
SDGs
Type
journal article