| Comparison between different earthquake magnitudes determined by China Seismograph Network |
| |
| 作者姓名： | 刘瑞丰 陈运泰 任枭 徐志国 孙丽 杨辉 梁建宏 任克新 |
| |
| 作者单位： | China Earthquake Networks Center，Institute of Geophysics China Earthquake Administration，China Earthquake Networks Center，China Earthquake Networks Center，China Earthquake Networks Center，China Earthquake Networks Center，China Earthquake Networks Center，China Earthquake Networks Center，Beijing 100045 China Institute of Geophysics China Earthquake Administration Beijing 100081 China，Beijing 100081 China，Beijing 100045 China，Beijing 100045 China，Beijing 100045 China，Beijing 100045 China，Beijing 100045 China，Beijing 100045 China |
| |
| 基金项目： | Special Project on Earthquake from Ministry of Science and Technology of China. Acknowledgements We express my sincere thanks to Prof. Peter Bormann in Germany＇s National Research Centre for Geosciences and Dr. Diethelm Kaiser in Federal Institute forGeodcienes and Natual Resources for the helps in method and software. |
| |
| 摘 要： | By linear regression and orthogonal regression methods, comparisons are made between different magnitudes (lo-cal magnitude ML, surface wave magnitudes MS and MS7, long-period body wave magnitude mB and short-period body wave magnitude mb) determined by Institute of Geophysics, China Earthquake Administration, on the basis of observation data collected by China Seismograph Network between 1983 and 2004. Empirical relations between different magnitudes have been obtained. The result shows that: 1 As different magnitude scales reflect radiated energy by seismic waves within different periods, earthquake magnitudes can be described more objectively by using different scales for earthquakes of different magnitudes. When the epicentral distance is less than 1 000 km, local magnitude ML can be a preferable scale; In case M<4.5, there is little difference between the magnitude scales; In case 4.5MS, i.e., MS underestimates magnitudes of such events, therefore, mB can be a better choice; In case M>6.0, MS>mB>mb, both mB and mb underestimate the magnitudes, so MS is a preferable scale for deter-mining magnitudes of such events (6.08.5, a saturation phenomenon appears in MS, which cannot give an accurate reflection of the magnitudes of such large events; 2 In China, when the epicentral distance is less than 1 000 km, there is almost no difference between ML and MS, and thus there is no need to convert be-tween the two magnitudes in practice; 3 Although MS and MS7 are both surface wave magnitudes, MS is in general greater than MS7 by 0.2~0.3 magnitude, because different instruments and calculation formulae are used; 4 mB is almost equal to mb for earthquakes around mB4.0, but mB is larger than mb for those of mB≥4.5, because the periods of seismic waves used for measuring mB and mb are different though the calculation formulae are the same.
|
| 关 键 词： | 地震 表面拨 等级 地震仪 |
| 文章编号： | 1000-9116（2007）05-0497-10 |
| 收稿时间： | 28 April 2007 |
| 修稿时间： | 2007-04-28 |
Comparison between different earthquake magnitudes determined by China Seismograph Network |
| |
| Liu Rui-feng , Chen Yun-tai , Ren Xiao , Xu Zhi-guo , Sun Li , Yang Hui , Liang Jian-hong and Ren Ke-xin.Comparison between different earthquake magnitudes determined by China Seismograph Network[J].Acta Seismologica Sinica(English Edition),2007,20(5):497-506. |
| |
| Authors: | Liu Rui-feng Chen Yun-tai Ren Xiao Xu Zhi-guo Sun Li Yang Hui Liang Jian-hong and Ren Ke-xin |
| |
| Institution: | 1. China Earthquake Networks Center, Beijing 100045, China; 2.Institute of Geophysics, China Earthquake Administration, Beijing 100081, China |
| |
| Abstract: | By linear regression and orthogonal regression methods, comparisons are made between different magnitudes (local magnitude
M
L, surface wave magnitudes M
S and M
S7, long-period body wave magnitude m
B and short-period body wave magnitude m
b) determined by Institute of Geophysics, China Earthquake Administration, on the basis of observation data collected by China
Seismograph Network between 1983 and 2004. Empirical relations between different magnitudes have been obtained. The result
shows that: ① As different magnitude scales reflect radiated energy by seismic waves within different periods, earthquake
magnitudes can be described more objectively by using different scales for earthquakes of different magnitudes. When the epicentral
distance is less than 1 000 km, local magnitude M
L can be a preferable scale; In case M<4.5, there is little difference between the magnitude scales; In case 4.5<M<6.0, m
B>
M
S, i.e., M
S underestimates magnitudes of such events, therefore, m
B can be a better choice; In case M>6.0, M
S>m
B>m
b, both m
B and m
b underestimate the magnitudes, so M
S is a preferable scale for determining magnitudes of such events (6.0<M<8.5); In case M>8.5, a saturation phenomenon appears in M
S, which cannot give an accurate reflection of the magnitudes of such large events; ② In China, when the epicentral distance
is less than 1 000 km, there is almost no difference between M
L and M
S, and thus there is no need to convert between the two magnitudes in practice; ③ Although M
S and M
S7 are both surface wave magnitudes, M
S is in general greater than M
S7 by 0.2∼0.3 magnitude, because different instruments and calculation formulae are used; ④ m
B is almost equal to m
b for earthquakes around m
B4.0, but m
B is larger than m
b for those of m
B≥4.5, because the periods of seismic waves used for measuring m
B and m
b are different though the calculation formulae are the same.
Foundation item: Special Project on Earthquake from Ministry of Science and Technology of China. |
| |
| Keywords: | local earthquake magnitude surface wave magnitude body wave magnitude |
| 本文献已被 CNKI 维普 SpringerLink 等数据库收录！ |
|
