Earthquake Of Magnitude Mw Research Articles

Geodetically observed surface displacements of the 1999 Chi-Chi, Taiwan, Earthquake

The 21 September 1999 Chi-Chi, Taiwan, earthquake of magnitude MW = 7.6 (ML = 7.3) severely deformed the Earth’s crust in the central Taiwan region. The earthquake created an 85-km-long surface rupture along the Chelungpu fault. The epicenter was located at 23.85°N, 120.81°E, near the southern end of the rupture zone. Three-dimensional displacements of 285 geodetic control stations were determined in this study from Global Positioning System (GPS) observations collected before and after the earthquake. The detailed surface displacement field shows that individual stations are vertically uplifted by up to 4 m and displaced horizontally by up to 9 m, with the largest displacement occurring near the northern end of the ruptured thrust fault. The azimuth of the surface displacement field is approximately parallel to the direction of tectonic convergence of the Eurasian and Philippine Sea plates. The maximum three-dimensional displacement of 9.9 m is among the largest fault movements ever measured for modern earthquakes.

The Seismotectonics of the 30 October 1998 Incline Village, Nevada Earthquake and Its Effects

INTRODUCTION On Friday, October 30, 1998, at 1:53 am local time (9:53:31 UT), an earthquake of magnitude Mw 4.9 (UNR) took place near the California-Nevada state border. The epicenter of the event was 7 km north-northwest of Incline Village, Nevada and the north shore of Lake Tahoe (39°18.14′N, 119°58.76′W) (see Figures 1 and 2). A focal depth of 10.5 ± 0.3 km and strike-slip focal mechanism suggest it is similar to other recent eastern Sierra Nevada-Western Basin and Range Extensional Province earthquakes (Rogers et al., 1991; Ichinose et al., 1998a). The earthquake occurred 4 km northwest of the surface trace of the northeast-striking North Tahoe-Incline Village Fault Zone, which is the largest fault zone in the area (Figure 2). This is a system of south-east-dipping normal faults, so the earthquake is well within the footwall of this fault zone. The Seismological Laboratory received felt reports, from which we assigned the...