The source rupture process of the MS7.0 Lushan earthquake was here evaluated using 40 long-period P waveforms with even azimuth coverage of stations.Results reveal that the rupture process of the Lushan MS7.0 event to...The source rupture process of the MS7.0 Lushan earthquake was here evaluated using 40 long-period P waveforms with even azimuth coverage of stations.Results reveal that the rupture process of the Lushan MS7.0 event to be simpler than that of the Wenchuan earthquake and also showed significant differences between the two rupture processes.The whole rupture process lasted 36 s and most of the moment was released within the first 13 s.The total released moment is 1.9×1019N m with MW=6.8.Rupture propagated upwards and bilaterally to both sides from the initial point,resulting in a large slip region of 40 km×30 km,with the maximum slip of 1.8 m,located above the initial point.No surface displacement was estimated around the epicenter,but displacement was observed about 20 km NE and SW directions of the epicenter.Both showed slips of less than 40 cm.The rupture suddenly stopped at 20 km NE of the initial point.This was consistent with the aftershock activity.This phenomenon indicates the existence of significant variation of the medium or tectonic structure,which may prevent the propagation of the rupture and aftershock activity.The earthquake risk of the left segment of Qianshan fault is worthy of attention.展开更多
An M6.5 earthquake occurred on August 3rd, 2014 in Ludian of Yunnan Province in China, causing severe casualty and economic loss. Local broadband waveform inversion with the CAP method demonstrates that the earthquake...An M6.5 earthquake occurred on August 3rd, 2014 in Ludian of Yunnan Province in China, causing severe casualty and economic loss. Local broadband waveform inversion with the CAP method demonstrates that the earthquake is a strike-slip event, with the strike along 70° and 160° for the two nodal planes respectively. However, the geological structure in the epicentral region is complicated with abundant active faults, and it is challenging to identify the seismogenic fault with the focal plane solutions due to nodal-plane ambiguity. We resolved the rupture directivity by measuring the difference between centroid location and hypocenter of the Ludian earthquake with the time shift from CAP inversion, and found that the nodal plane with the strike of 160° is the ruptured fault plane. Moreover, the rupture is found to propagate from northwest to southeast.展开更多
基金supported by the National Natural Science Foundation of China(41104033)the Basic Research Project of Institute of Earthquake Science,CEA(2011IES010104)
文摘The source rupture process of the MS7.0 Lushan earthquake was here evaluated using 40 long-period P waveforms with even azimuth coverage of stations.Results reveal that the rupture process of the Lushan MS7.0 event to be simpler than that of the Wenchuan earthquake and also showed significant differences between the two rupture processes.The whole rupture process lasted 36 s and most of the moment was released within the first 13 s.The total released moment is 1.9×1019N m with MW=6.8.Rupture propagated upwards and bilaterally to both sides from the initial point,resulting in a large slip region of 40 km×30 km,with the maximum slip of 1.8 m,located above the initial point.No surface displacement was estimated around the epicenter,but displacement was observed about 20 km NE and SW directions of the epicenter.Both showed slips of less than 40 cm.The rupture suddenly stopped at 20 km NE of the initial point.This was consistent with the aftershock activity.This phenomenon indicates the existence of significant variation of the medium or tectonic structure,which may prevent the propagation of the rupture and aftershock activity.The earthquake risk of the left segment of Qianshan fault is worthy of attention.
基金supported by the National Natural Science Foundation of China(Grant No.41274069)National Basic Research Program of China(Grant No.2014CB845901)
文摘An M6.5 earthquake occurred on August 3rd, 2014 in Ludian of Yunnan Province in China, causing severe casualty and economic loss. Local broadband waveform inversion with the CAP method demonstrates that the earthquake is a strike-slip event, with the strike along 70° and 160° for the two nodal planes respectively. However, the geological structure in the epicentral region is complicated with abundant active faults, and it is challenging to identify the seismogenic fault with the focal plane solutions due to nodal-plane ambiguity. We resolved the rupture directivity by measuring the difference between centroid location and hypocenter of the Ludian earthquake with the time shift from CAP inversion, and found that the nodal plane with the strike of 160° is the ruptured fault plane. Moreover, the rupture is found to propagate from northwest to southeast.
