Co-Seismic Surface Rupture and Recurrence Interval of Large Earthquakes along Damaoyaba-Litang Segment of the Litang Fault on the Eastern Margin of the Tibetan Plateau in China

• 作者: Shiyuan Wang Rongjun Zhou Mingjian Liang Shao Liu Nina Liu Jianyu Long
• 来源期刊: 地球科学学刊（英文版）
• 年，卷（期）: 2021,（5）
• 所属期刊栏目: Special Issue on Geo-Disasters
• 页码范围: 1139-1151
• 页数: 13页
• 语种: 英文

摘要

The Litang fault is a left-lateral secondary shear zone in the Sichuan-Yunnan active block that accommodates the tectonic deformation associated with the eastward extrusion of the upper crust of the Tibetan Plateau. Based on 1 : 50000 geological mapping of active faults, the Litang fault consists of three geometric segments, the Cuopuhu, Damaoyaba, and Litang segments, in the west of Litang, which are divided by the of Haizi Mountain uplift and the wide-angle bending and branching of the fault near Jinchanggou. This study also identifies the surface rupture of the A.D. 1890 earthquake, which is distrib-uted intermittently along the ～28 km long Damaoyaba segments and ～25 km long Litang segments. The maximum horizontal displacement is 4.1 m along Damaoyaba segments, and 4 m along Litang segments. The rupture involves typical left-lateral shear movement. The two ruptures are divided by discontinuous segments or gaps that are ～18 km long; thus, the total surface rupture is approximately 71 km long. The estimated moment magnitude was Mw7.3±0.1. A comprehensive analysis of data obtained from 5 trenches excavated along the Damaoyaba and Litang segments and the trench data by Xu et al. (2005) identifies age constraints of the 4 most recent paleoseimic events occurred B.C. 1468±54-1340±25, B.C. 52±25-A.D. 76±47, A.D. 1115±90, and A.D. 1890, respectively. The recurrence intervals are 1415±80, 1104±104, and 775±90 a, which are consistent with quasi-periodic earthquake recurrence behavior. The average recur-rence interval is 1098±112 a.