Taiwan Ground Failure Database
Documentation of Soil Conditions at Liquefaction Sites from 1999 Chi-Chi, Taiwan Earthquake
Collaborative Research by U.C.L.A., National Chung-Hsing University, National Cheng-Kung University, National Chi-Nan University, and U.C. Berkeley
Significant occurrences of ground failure in the form of liquefaction, ground softening, and lateral spreading were documented by NSF-sponsored reconnaissance teams in several areas affected by the 1999 Chi-Chi earthquake (Mw = 7.6). The goal of this project was to characterize the subsurface conditions at sites where ground deformations and/or building movements (or the lack of such deformations and movements) were well documented.
Site characterization consisted of cone penetration testing (some with pore pressure and shear wave velocity measurements) and rotary wash borings with standard penetration testing (with energy measurements). Field work sponsored by the Pacific Earthquake Engineering Research (PEER) center occurred primarily in two locations, Wufeng and Nantou, where significant ground failure occurred and shaking levels were high. Through a memorandum of understanding with Taiwan's National Center for Research in Earthquake Engineering (NCREE), access was secured to an additional large data set for Nantou, Wufeng, and Yuanlin. Additional data has been secured from a private consulting firm (Resource Engineering Services Inc.) for a portion of Wufeng. Results from all three field exploration programs are presented in this web page in a consistent format.
In addition to the cone penetration and borehole data, shear wave velocity data from SASW (spectral analysis of surface wave) tests are also reported. These tests were performed by Dr. Robert Kayen with sponsorship from PEER and USGS.
Project Benefits for California
The goal of California’s Seismic Hazards Mapping Act is "to protect public safety from the effects of strong ground shaking, liquefaction, landslides, or other ground failure, and other hazards caused by earthquakes" (CDMG SP-117, 1997). The seismic hazards mapping effort is largely based on empirical methods that require re-evaluation and updating as important case histories emerge. The Chi-Chi, Taiwan earthquake represents an important source of case histories, including hundreds of structures that settled and tilted due to liquefaction and ground softening. Study of these case histories will enable earthquake engineers to develop much-needed, rational analysis and design procedures to address hazards posed by ground failure. In summary, observations from design level earthquakes are invaluable to advancing the state-of-practice in earthquake engineering, and lessons learned from observations of ground failure in Taiwan are transferable to California.