Characters of Surface Displacement Due to Blind Curved Fault Revealed by Numerical Models
详细信息
- 责任者：Zhang Zhuqi (State Key Laboratory of Earthquake Dynamics ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Chen Tao
- 刊名：Seismology and Geology
- 出版年：2013
- 卷期：35(2)
- 关键词：断层 ; faults ; 地震 ; earthquakes ; 四川 ; Sichuan Province
- 页码：p.452-460
- 图表：illus., 20 refs.
- 分类号：0500
- issnNo：ISSN0253-4967
- isbnNo：CN11-2192/P
摘要
A possible three-dimensionally highly-curved fault,suspected as the ruptured structure of the Lushan M7. 0 earthquake,is revealed by relocated aftershocks. A recent study shows that obvious differences exist between curved fault and straight fault under the ground in regard to dislocation patterns and co-seismic stress responses on the planes ruptured during an earthquake. Infinite halfspace dislocation models reveal that the characters of surface displacements due to a curved fault are similar to that from straight reverse fault as a whole. Nevertheless,the horizontal displacements due to slip on a curved fault show closer trend parallel to the direction of regional shortening and higher magnitude than that from a straight fault. Subsequently,the curved fault is suggested to be more capable of transferring horizontal movement of hanging-wall materials in large area. Relative to the case on a straight fault,horizontal displacement in foot-wall area of a curved fault decays more with distance from source fault. On the other hand,the curved fault generates obviously less co-seismic uplift while larger and more extensive surface drop somewhere than the reverse fault or left-lateral reverse fault of the same size but with straight fault planes does. For relatively small magnitude of main shock,it is not easy to determine whether the structure of rupture during Lushan earthquake is highly-curved fault or not due to the sparse observations on co-seismic deformation like GPS. Dense and high-resolution observations should be required to survey the features of focal structure in detail.