COMMON EARTHQUAKE EFFECTS - Geotechnical Earthquake Engineering - page 34

FIGURE 3.1 Surface fault rupture associated with the El Asnam (Algeria) earthquake on October 10, 1980.
( Photograph from the Godden Collection, EERC, University of California, Berkeley. )

(Florensov and Solonenko 1965). The length of the fault rupture can be quite significant.
For example, the estimated length of surface faulting in the 1964 Alaskan earthquake var-
ied from 600 to 720 km (Savage and Hastie 1966, Housner 1970).

3.2.2 Damage Caused by Surface Rupture

Surface fault rupture associated with earthquakes is important because it has caused severe
damage to buildings, bridges, dams, tunnels, canals, and underground utilities (Lawson et
al. 1908, Ambraseys 1960, Duke 1960, California Department of Water Resources 1967,
Bonilla 1970, Steinbrugge 1970).
There were spectacular examples of surface fault rupture associated with the Chi-chi
(Taiwan) earthquake on September 21, 1999. According to seismologists at the U.S.
Geological Survey, National Earthquake Information Center, Golden, Colorado, the tec-
tonic environment near Taiwan is unusually complicated. They state (USGS 2000a):

Tectonically, most of Taiwan is a collision zone between the Philippine Sea and Eurasian
plates. This collision zone is bridged at the north by northwards subduction of the Philippine
Sea plate beneath the Ryuku arc and, at the south, an eastwards thrusting at the Manila trench.
The northern transition from plate collision to subduction is near the coastal city of Hualien,
located at about 24 degrees north, whereas the southern transition is 30-50 kilometers south of
Taiwan.

With a magnitude of 7.6, the earthquake was the strongest to hit Taiwan in decades and
was about the same strength as the devastating tremor that killed more than 17,000 people