• 责任者：Zhang Zhuqi (State Key Laboratory of Earthquake Dynamics ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Zhang Peizhen
• 刊名：Chinese Journal of Geophysics
• 出版年：2010
• 卷期：53(9)
• 关键词：逆断层 ; reverse faults ; 孕震构造 ; seismogenic tectonics ; 龙门山断裂带 ; Longmenshan Fault Zone
• 页码：p.2068-2082
• 图表：9 illus., 1 table, 53 refs.
• 分类号：0500
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

zhang>In this paper, the authors focus on the 2D character of fault shape versus depth, i.e., the dip of fault segments and corresponding depth. On the basis of geometrical features of co-seismic fault, the authors further discuss how stress accumulated before the Wenchuan earthquake and why such steep reverse fault is capable of moving. Using subspace trust region method for non-linear problems to fit the co-seismic near field leveling data, the authors obtain 2D elastic dislocation models respectively corresponding to two co-seismic fault segments of Qingping-Beichuan and Nanba-Qingchuan segment. The results display apparent geometrical diversity along middle Longmenshan thrust belt from south to north. Lying south to the Beichuan-Nanba transition zone, the sub-fault breaking through south Beichuan to Qingping is featured by a duplex faulting system, which is divided into two layers in depth. Moreover, the authors speculate that the sub-fault lying south to Qingping is also a duplex faulting system. On the other hand, the vertical extension caused by the differential uplift may balance a certain amount of lithostatic pressure, which is prone to cause deficient vertical principle compression against fluid pressure and consequently provides an essential condition for earthquakes on high dip-angle reverse fault.