The Earthquake Engineering Online Archive

Studies of strong ground motion in Taiwan

Hsiung, Y. M.; Bolt, Bruce A.; Penzien, Joseph

UCB/EERC-78/26, Earthquake Engineering Research Center, University of California, Berkeley, 1978-11, 114 pages (380.6/H75/1978)

In Part I of this report, a general analysis is made of the characteristics of three strong ground motion records obtained from a moderate earthquake near Wufeng, on Apr. 14, 1976. Both time and frequency domain techniques are used. The intensity function has a single peak shape, which suggests that the fault mechanism is simple. Using an intensity function of this shape, the general pattern of the ground motion is simulated. A comparison of these simulated motions with the recorded ground motions shows similar characteristics. The frequency domain analysis indicates that the predominant frequency is about 2.5 Hz. The interpretation of the fault-plane solution, which appears to give the best explanation of the strong ground motion records, is that the fault is a left-lateral thrust with N41 degree E strike and 36 degree SE dip. Although this interpretation is different from that of CERC obtained from sensitive seismographs, it agrees well with almost all the strong-motion records. In part II of this report, the problem of risk maps is examined using the distribution of seismic intensity both in time and space in Taiwan. In this study, instead of the Poisson distribution for earthquake occurrence, a modified hazard distribution is adopted. This distribution allows a dependence between successive earthquakes. Hazard contour maps have been drawn using this method for 13 cases. These are compared with various risk map estimates, by other authors, having the same general tendencies.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-78-26.pdf (44 MB)