Abstract
Seismograms and accelerograms from 77 earthquakes in 1982 to 1984 near the northwest end of the Red River fault in western Yunnan Province, Peoples Republic of China, have been used to calculate seismic moment, M0, and local magnitude, ML, using techniques established in California. For ≲ ML ≲ , log M0 = 16.97 + (1.17 ± 0.05)ML, consistent with the log M0 − ML relation appropriate for central California. A comparison of these ML values and the coda duration magnitudes M and S-wave amplitude magnitudes M˜ assigned by the Seismological Bureau of Yunnan Province suggests that M and M˜ values are generally larger than the ML values. For 1.7 ≦ M ≦ 5.3, ML = 0.49 + (0.67 ± 0.04) M and log M0 = 17.30 + (0.86 ± 0.04) M. For 2.0 ≦ M˜ ≦ 5.4, ML = 0.24 + (0.76 ± 0.05)M˜ and log M0 = 17.06 + (0.95 ± 0.05)M˜.