Monitoring active fault creep as a tool in seismic hazard mitigation. Insights from creepmeter study at Chihshang, Taiwan

In 1998 we installed five creepmeters across the Chihshang Fault, the active plate suture in eastern Taiwan. Daily creepmeter data indicated decreasing creeping rate from 1999 to 2003, suggesting increasing seismic hazard. The fault was ruptured by the Chengkung earthquake ( Mw = 6.6 ) on 10 December 2003. Through extrapolation of our earlier creep data of 1986–1991 and 1992–1997, we evaluate the minimum deficit in aseismic creep shortening as 106 or 46 mm (respectively) before this earthquake. The near-surface co-seismic shortening was limited, but the total shortening resulting from the earthquake, including post-seismic creep, was about 97 mm. This suggests that near the surface most of the detectable deficit has been absorbed by this earthquake and subsequent creep. We thus point out that creepmeter installation and monitoring bring a powerful tool in seismic hazard mitigation. To cite this article: J.-C. Lee et al., C. R. Geoscience 337 (2005).