Vertical records are critically important when determining the rupture model of an earthquake, especially a thrust earthquake. Due to the relatively low fitness level of near-field vertical displacements, the precisio...Vertical records are critically important when determining the rupture model of an earthquake, especially a thrust earthquake. Due to the relatively low fitness level of near-field vertical displacements, the precision of previous rupture models is relatively low, and the seismic hazard evaluated thereafter should be further updated. In this study, we applied three-component displacement records from GPS stations in and around the source region of the 2013 MW6.6 Lushan earthquake to re-investigate the rupture model.To improve the resolution of the rupture model, records from both continuous and campaign GPS stations were gathered, and secular deformations of the GPS movements were removed from the records of the campaign stations to ensure their reliability. The rupture model was derived by the steepest descent method（SDM）, which is based on a layered velocity structure. The peak slip value was about 0.75 m, with a seismic moment release of 9.89 × 1018 N·m, which was equivalent to an MW6.6 event. The inferred fault geometry coincided well with the aftershock distribution of the Lushan earthquake. Unlike previous rupture models, a secondary slip asperity existed at a shallow depth and even touched the ground surface. Based on the distribution of the co-seismic ruptures of the Lushan and Wenchuan earthquakes, post-seismic relaxation of the Wenchuan earthquake, and tectonic loading process, we proposed that the seismic hazard is quite high and still needs special attention in the seismic gap between the two earthquakes.展开更多
Co-seismic deformation and gravity field changes caused by the 2011 Mw6. 8 Myanmar and Mw6. 9 India-Nepal earthquakes are calculated with a finite-element model and an average-slip model, respectively, based on the mu...Co-seismic deformation and gravity field changes caused by the 2011 Mw6. 8 Myanmar and Mw6. 9 India-Nepal earthquakes are calculated with a finite-element model and an average-slip model, respectively, based on the multi-layered elastic half-space dislocation theory. The calculated maximum horizontal displace- ment of the Myanmar earthquake is 36 era, which is larger than the value of 9. 5 cm for the India-Nepal earth- quake. This difference is attributed to their different focal depths and our use of different models. Except cer- tain differences in the near field, both models give similar deformation and gravity results for the Myanmar event.展开更多
基金supported by the grant from the National Sichuan-Yunnan earthquake prediction experimental field of CEA (grant No. 2016CESE0204)
文摘Vertical records are critically important when determining the rupture model of an earthquake, especially a thrust earthquake. Due to the relatively low fitness level of near-field vertical displacements, the precision of previous rupture models is relatively low, and the seismic hazard evaluated thereafter should be further updated. In this study, we applied three-component displacement records from GPS stations in and around the source region of the 2013 MW6.6 Lushan earthquake to re-investigate the rupture model.To improve the resolution of the rupture model, records from both continuous and campaign GPS stations were gathered, and secular deformations of the GPS movements were removed from the records of the campaign stations to ensure their reliability. The rupture model was derived by the steepest descent method（SDM）, which is based on a layered velocity structure. The peak slip value was about 0.75 m, with a seismic moment release of 9.89 × 1018 N·m, which was equivalent to an MW6.6 event. The inferred fault geometry coincided well with the aftershock distribution of the Lushan earthquake. Unlike previous rupture models, a secondary slip asperity existed at a shallow depth and even touched the ground surface. Based on the distribution of the co-seismic ruptures of the Lushan and Wenchuan earthquakes, post-seismic relaxation of the Wenchuan earthquake, and tectonic loading process, we proposed that the seismic hazard is quite high and still needs special attention in the seismic gap between the two earthquakes.
基金supported by grant 201008007 from China Earthquake Administration,National Natural Science Foundation of China(40974034,41174086)
文摘Co-seismic deformation and gravity field changes caused by the 2011 Mw6. 8 Myanmar and Mw6. 9 India-Nepal earthquakes are calculated with a finite-element model and an average-slip model, respectively, based on the multi-layered elastic half-space dislocation theory. The calculated maximum horizontal displace- ment of the Myanmar earthquake is 36 era, which is larger than the value of 9. 5 cm for the India-Nepal earth- quake. This difference is attributed to their different focal depths and our use of different models. Except cer- tain differences in the near field, both models give similar deformation and gravity results for the Myanmar event.
