Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

46 Katsuyuki AbeTable 3. Sinkiang Earthquake of December 22, 1906S tat ionIrkutskCalcuttaBombayKod ai kana1ColomboBeirutHelwanBat av i aEd in burghKe wPaisleyHaslemereBidstonShideSan FernandoAzoresPerthVictoriaTorontoHonoluluBaltimoreSydneyCape of Good HopeCordobaAverageDistance(ded15.021.427.234.337.239.744.953.454.555.255.255.655.756.167.077.780.484.791.892.895.797.798.6153.1Arrivaltime(hr:mn)18:31.218:39.118:42.218:42.318:48.518:39.518:55.618:52.518:55.018:56.718:54.31856.818:53.518:59.319:11.919: 12.819:17.719:23.019:18.219:24.319:18.219:19.019:54.6Values in the parentheses are not used in the average.OrigintimeA MS(hr:mn) (mm)18:21.9 >17.0 (6.85)14.0 6.9118:22.3 9.0 7.0318:21.O 5 .O 7.0518:19.3 11.5 7.4518:24.0 2.5 6.79(18A1.8) 2.2 6.7518:22.6 2.9 7.0918:18.8 6.5 7.3618 :20.9 11.4 7.4618:22.6 14.0 7.7018 :20 .O 14.3 7.4218:22.418:18.8 >15.0 (7.40)18:17.9 8.9 7.2618:23.9 1.4 7.1818:23.1 1 .o 6.89(18:25.4) 4.0 7.73(18:26.3) 3.2 7.5818:ZO.Q 6.5 7.68(18:25.2) 6.5 7.73(18:17.8) 0.65 6.9818:18.1 3.8 7.5228:20.0 0.9 7.4118:21.0 7.28'Maximum Waves" , origin time calculated from (3), maximum trace amplitudes andvalues of Ms. The station correction has been incorporated in the Ms estimates.Ten shocks in Table 2 are listed by Duda (1965), and their values of Ms areon average 0.5 smaller than the Duda's magnitudes. The largest difference is 1.0.A discussion about the scale used by Duda has been made elsewhere (Abe, 1981,1984). Duda lists the earthquake of March 2, 1906. Its epicenter (43' N, 80' E) islocated marginally outside China. The origin time and Ms from the 17 Milne datahave been estimated to be 06:15.1 f 1.7 and 6.36 zt 0.18, respectively. This valueof Ms is considerably smaller than 7.3 given by Duda.Data of instrumentally determined origin times are very few for early shocks. Thetime for CH18 has been noted before. The origin times for CH24 and CH30 aregiven by Gutenberg and Richter (1954). The time for CH24 has been estimated tobe 14:47.5 f 1.0 from 19 Milne data, while Gutenberg and Richter (1954) calculatedit to be 14:49.5 from 6 stations. There is no difference for CH30.The earthquake of CH28 with Ms = 6.8 is not listed in the previous catalog ofAbe and Noguchi (1983) which lists world earthquakes with Ms = 6.8 or above.This magnitude has been increased from 6.7 owing to the inclusion of station corrections.For the same reason, values of Ms for CH03, CHO9 and CH18 are differentby 0.1 unit from the previous catalog.