The relationships between Earth＇s rotation and the 1975 Haicheng, Liaoning Ms7.3 earthquake, 2008 Wenchuan, Sichuan Ms8.0 earthquake and the 2004 Sumatra Msg. 0 earthquake, as well as moderate-small earthquakes occur...The relationships between Earth＇s rotation and the 1975 Haicheng, Liaoning Ms7.3 earthquake, 2008 Wenchuan, Sichuan Ms8.0 earthquake and the 2004 Sumatra Msg. 0 earthquake, as well as moderate-small earthquakes occurring around the epicenter regions prior to them are investigated in this study. The obtained results could benefit the further understanding of the relationship between the Earth＇s rotation and earthquakes.展开更多
The change laws of intensity of nearly 200 moderate-small earthquakes with Ms=2.0~5.5 occurring on the Chinese mainland since 1954 have been analyzed and are compared with that of moderately strong earthquakes(Ms≥5.0...The change laws of intensity of nearly 200 moderate-small earthquakes with Ms=2.0~5.5 occurring on the Chinese mainland since 1954 have been analyzed and are compared with that of moderately strong earthquakes(Ms≥5.0).The results show that there is quite obvious regionality in the statistical laws by both moderate-small earthquakes and moderately strong earthquakes:attenuation of intensity in Eastern China is slower than that in Western China and the ratio of the major axis to the minor axis of iso-seismal lines in Eastern China is smaller than that in Western China.The results also show that for a fixed magnitude the attenuation of intensity of moderate-small earthquakes is faster when intensity is higher than V+ and slower when intensity is lower than V-in comparison with that of moderately strong earthquakes.Furthermore,there also have been some differences in the aspects as intensity-magnitude relation between statistical laws of moderate-small earthquakes and moderately strong earthquakes.These展开更多
The great Tancheng earthquake of M81/2 occurred in 1668 was the largest seismic event ever recorded in history in eastern China. This study determines the fault geometry of this earthquake by inverting seismological ...The great Tancheng earthquake of M81/2 occurred in 1668 was the largest seismic event ever recorded in history in eastern China. This study determines the fault geometry of this earthquake by inverting seismological data of present-day moderate-small earthquakes in the focal area. We relocated those earthquakes with the double-difference method and found focal mechanism solutions using gird test method. The inversion results are as follows： the strike is 21.6°, the dip angle is 89.5°, the slip angle is 170°, the fault length is about 160 km, the lower-boundary depth is about 32 km and the buried depth of upper boundary is about 4 km. This shows that the seismic fault is a NNE-trending upright right-lateral strike-slip fault and has cut through the crust. Moreover, the surface seismic fault, intensity distribution of the earthquake, earthquake-depth distribution and seismic-wave velocity profile in the focal area all verified our study result.展开更多
基金sponsored by the Teacher's Scientific Research Fund of the China Earthquake Administration(20090103)
文摘The relationships between Earth＇s rotation and the 1975 Haicheng, Liaoning Ms7.3 earthquake, 2008 Wenchuan, Sichuan Ms8.0 earthquake and the 2004 Sumatra Msg. 0 earthquake, as well as moderate-small earthquakes occurring around the epicenter regions prior to them are investigated in this study. The obtained results could benefit the further understanding of the relationship between the Earth＇s rotation and earthquakes.
文摘The change laws of intensity of nearly 200 moderate-small earthquakes with Ms=2.0~5.5 occurring on the Chinese mainland since 1954 have been analyzed and are compared with that of moderately strong earthquakes(Ms≥5.0).The results show that there is quite obvious regionality in the statistical laws by both moderate-small earthquakes and moderately strong earthquakes:attenuation of intensity in Eastern China is slower than that in Western China and the ratio of the major axis to the minor axis of iso-seismal lines in Eastern China is smaller than that in Western China.The results also show that for a fixed magnitude the attenuation of intensity of moderate-small earthquakes is faster when intensity is higher than V+ and slower when intensity is lower than V-in comparison with that of moderately strong earthquakes.Furthermore,there also have been some differences in the aspects as intensity-magnitude relation between statistical laws of moderate-small earthquakes and moderately strong earthquakes.These
基金supported by the National Natural Science Foundation of China(No.90814002)the Natural Science Foundation of Shandong Province(No.Y2005E02)
文摘The great Tancheng earthquake of M81/2 occurred in 1668 was the largest seismic event ever recorded in history in eastern China. This study determines the fault geometry of this earthquake by inverting seismological data of present-day moderate-small earthquakes in the focal area. We relocated those earthquakes with the double-difference method and found focal mechanism solutions using gird test method. The inversion results are as follows： the strike is 21.6°, the dip angle is 89.5°, the slip angle is 170°, the fault length is about 160 km, the lower-boundary depth is about 32 km and the buried depth of upper boundary is about 4 km. This shows that the seismic fault is a NNE-trending upright right-lateral strike-slip fault and has cut through the crust. Moreover, the surface seismic fault, intensity distribution of the earthquake, earthquake-depth distribution and seismic-wave velocity profile in the focal area all verified our study result.
