Four results of the rupture process of 14 April 2010 Yushu, Qinghai, earthquake, obtained by inverting the broadband seismic data of Global Seismographic Network （GSN） based on the inversion method of earthquake rup...Four results of the rupture process of 14 April 2010 Yushu, Qinghai, earthquake, obtained by inverting the broadband seismic data of Global Seismographic Network （GSN） based on the inversion method of earthquake rupture process, were compared and discussed. It is found that the Yushu earthquake has several basic characteristics as follows： 1 There exist two principal sub-events which correspond to two slip-concentrated patches being located near the hypocenter and to the southeast of the epicenter. The rupture of the slip-concentrated patch to the southeast of the epicenter broke though the ground surface; 2 The peak slip and peak slip-rate are about 2.1 m and 1.1 m/s, respectively, indicating that the Yushu earthquake is an event with large slip-rate on the fault plane; 3 Overall the Yushu earthquake is a unilateral rupture event with the rupture mainly propagating southeastward. The strong focusing of the seismic energy in the southeast of the epicenter due to the ＂seismic Doppler effect＂ reasonably accounts for the tremendous damage in the Yushu city.展开更多
The 2010 Mw 6.9 Yushu earthquake produced a ~33-km-long co-seismic surface rupture zone along the pre-existing active Yushu Fault on China’s central Tibetan Plateau. Sand boils occurred along the tension cracks of th...The 2010 Mw 6.9 Yushu earthquake produced a ~33-km-long co-seismic surface rupture zone along the pre-existing active Yushu Fault on China’s central Tibetan Plateau. Sand boils occurred along the tension cracks of the co-seismic surface rupture zone, and locally spouted up above the ground to coat the top of limestone blocks that had slid down from an adjacent ~300-m-high mountain slope. Based on our observations, the relations between the arrival times of P- and S-waves at the sand-boil location and the seismic rupture velocity, we conclude that 1) the sand boils occurred at least 18.24 s after the main shock;2) it took at least 4.09 - 9.79 s after the formation of co-seismic surface rupture to generate liquefaction at the sand-boil location;3) the spouting height of sand boils was at least 65 cm. Our findings help to clarify the relationships between the timing of lique-faction and the spouting height of sand boils during a large-magnitude earthquake.展开更多
The authors studied the seismic activity, precursory anomalies and abnormal animal behavior before the April 14, 2010 Ms 7.1 Yushu earthquake. Analysis showed that anomalies were not rich before the Ms 7.1 Yushu earth...The authors studied the seismic activity, precursory anomalies and abnormal animal behavior before the April 14, 2010 Ms 7.1 Yushu earthquake. Analysis showed that anomalies were not rich before the Ms 7.1 Yushu earthquake, but prominent anomalies were observed, such as the long and mid-term trend anomaly characterized by the seismic quiescence of Ms6. 0, MsS. 0 and Ms4.0 earthquakes, and the anomalies in precursor observation of surface water temperature in Yushu and Delingha and electromagnetic measurement in Ping＇an. There were a large number of animal behavior anomalies appearing one week before the earthquake. An M4.7 earthquake occurred 130 minutes before the main shock. In this paper, we studied the dynamic process of the Yushu earthquake preparation using the earthquake focal mechanism solutions on the Bayan Har block boundary since 1996. The results show that the Kalakunlun M7.1 earthquake in 1996, the Mani M7.5 earthquake and the Yushu Ms7.1 earthquake have the same dynamic process. Long and mid-term trend anomalies may be related to the dynamics of evolution of different earthquakes. This paper also discusses the recurrence interval of strong earthquakes, foreshock identification and precursor observation of the Yushu Ms7. 1 earthquake.展开更多
In the early morning of April 14th, 2010, a strong earth- quake (Ms7.1, http://www.csndmc.ac.cn; Mw6.9, http://neic. usgs.gov) occurred in Yushu district, Qinghai Province, China. More than 2000 lives were lost and ov...In the early morning of April 14th, 2010, a strong earth- quake (Ms7.1, http://www.csndmc.ac.cn; Mw6.9, http://neic. usgs.gov) occurred in Yushu district, Qinghai Province, China. More than 2000 lives were lost and over 100000 injured,展开更多
The comprehensive waveform analysis of the Love waves and P waves shows that the Yushu M S7.1 (M W6.9) earthquake consists of two distinct sub-events. The first one occurred in the first 5 s releasing less seismic mom...The comprehensive waveform analysis of the Love waves and P waves shows that the Yushu M S7.1 (M W6.9) earthquake consists of two distinct sub-events. The first one occurred in the first 5 s releasing less seismic moment, and the second occurred in the later 11 s releasing more seismic moment. Spatially, the first sub-event surrounded the hypocenter, and the second, about 30 km away from the first, was much closer to the Yushu city and broke through the ground surface. In terms of the rupture velocity to which the peak values of the two sub-events correspond, the first sub-event propagated with an average rupture velocity of 1.6 km/s, however, the second propagated with an average rupture velocity of 4.0 km/s which is actually superior to the shear-wave velocity in the hypocentral region. The magnitude of the Yushu earthquake is in the lower margin of large earthquakes. The results obtained in this study indicate that the super-shear rupture possibly appears in earthquakes with magnitude of around 7.0, instead of only in the great earthquakes with magnitude around 8.0 [14, 15]. In addition, the energy focusing caused by the super-shear rupture should take key responsibility for the tremendous damage to the Yushu city as well as the ground-surface breakage related to the larger second sub-event.展开更多
基金supported by China Postdoctoral Science Foundation funded project (20080440435)the project (DQJB09B06) from Institute of Geophysics (IGP),China Earthquake Administration (CEA). Contribution No. is 10FE3002, IGP-CEA
文摘Four results of the rupture process of 14 April 2010 Yushu, Qinghai, earthquake, obtained by inverting the broadband seismic data of Global Seismographic Network （GSN） based on the inversion method of earthquake rupture process, were compared and discussed. It is found that the Yushu earthquake has several basic characteristics as follows： 1 There exist two principal sub-events which correspond to two slip-concentrated patches being located near the hypocenter and to the southeast of the epicenter. The rupture of the slip-concentrated patch to the southeast of the epicenter broke though the ground surface; 2 The peak slip and peak slip-rate are about 2.1 m and 1.1 m/s, respectively, indicating that the Yushu earthquake is an event with large slip-rate on the fault plane; 3 Overall the Yushu earthquake is a unilateral rupture event with the rupture mainly propagating southeastward. The strong focusing of the seismic energy in the southeast of the epicenter due to the ＂seismic Doppler effect＂ reasonably accounts for the tremendous damage in the Yushu city.
文摘The 2010 Mw 6.9 Yushu earthquake produced a ~33-km-long co-seismic surface rupture zone along the pre-existing active Yushu Fault on China’s central Tibetan Plateau. Sand boils occurred along the tension cracks of the co-seismic surface rupture zone, and locally spouted up above the ground to coat the top of limestone blocks that had slid down from an adjacent ~300-m-high mountain slope. Based on our observations, the relations between the arrival times of P- and S-waves at the sand-boil location and the seismic rupture velocity, we conclude that 1) the sand boils occurred at least 18.24 s after the main shock;2) it took at least 4.09 - 9.79 s after the formation of co-seismic surface rupture to generate liquefaction at the sand-boil location;3) the spouting height of sand boils was at least 65 cm. Our findings help to clarify the relationships between the timing of lique-faction and the spouting height of sand boils during a large-magnitude earthquake.
基金funded by Earthquake Tendency Tracing of 2011 of Department of Monitoring and Prediction of CEA under the"Earthquake Short and Imminent Prediction Climb Program of2020"(2011016301)
文摘The authors studied the seismic activity, precursory anomalies and abnormal animal behavior before the April 14, 2010 Ms 7.1 Yushu earthquake. Analysis showed that anomalies were not rich before the Ms 7.1 Yushu earthquake, but prominent anomalies were observed, such as the long and mid-term trend anomaly characterized by the seismic quiescence of Ms6. 0, MsS. 0 and Ms4.0 earthquakes, and the anomalies in precursor observation of surface water temperature in Yushu and Delingha and electromagnetic measurement in Ping＇an. There were a large number of animal behavior anomalies appearing one week before the earthquake. An M4.7 earthquake occurred 130 minutes before the main shock. In this paper, we studied the dynamic process of the Yushu earthquake preparation using the earthquake focal mechanism solutions on the Bayan Har block boundary since 1996. The results show that the Kalakunlun M7.1 earthquake in 1996, the Mani M7.5 earthquake and the Yushu Ms7.1 earthquake have the same dynamic process. Long and mid-term trend anomalies may be related to the dynamics of evolution of different earthquakes. This paper also discusses the recurrence interval of strong earthquakes, foreshock identification and precursor observation of the Yushu Ms7. 1 earthquake.
基金supported by Chinese Academy of Science Fund (Grant No. KZCX2-YW-116-1)China Earthquake Administration Fund (Grant No. 200808078)
文摘In the early morning of April 14th, 2010, a strong earth- quake (Ms7.1, http://www.csndmc.ac.cn; Mw6.9, http://neic. usgs.gov) occurred in Yushu district, Qinghai Province, China. More than 2000 lives were lost and over 100000 injured,
基金supported by National Natural Science Foundation of China (Grant Nos.40904013,40874026)Institue of Geophysics,China Earthquake Administration (Grant No.DQJB09B06)
文摘The comprehensive waveform analysis of the Love waves and P waves shows that the Yushu M S7.1 (M W6.9) earthquake consists of two distinct sub-events. The first one occurred in the first 5 s releasing less seismic moment, and the second occurred in the later 11 s releasing more seismic moment. Spatially, the first sub-event surrounded the hypocenter, and the second, about 30 km away from the first, was much closer to the Yushu city and broke through the ground surface. In terms of the rupture velocity to which the peak values of the two sub-events correspond, the first sub-event propagated with an average rupture velocity of 1.6 km/s, however, the second propagated with an average rupture velocity of 4.0 km/s which is actually superior to the shear-wave velocity in the hypocentral region. The magnitude of the Yushu earthquake is in the lower margin of large earthquakes. The results obtained in this study indicate that the super-shear rupture possibly appears in earthquakes with magnitude of around 7.0, instead of only in the great earthquakes with magnitude around 8.0 [14, 15]. In addition, the energy focusing caused by the super-shear rupture should take key responsibility for the tremendous damage to the Yushu city as well as the ground-surface breakage related to the larger second sub-event.
