Analysis of Holocene Faulting Phenomena Revealed in the Three Trenches along the Northern and Central Jiaocheng Fault, Shanxi Province
详细信息
- 责任者：Guo Hui (Institute of Crustal Dynamics ; China Earthquake Administration ; Beijing 100085 ; China) ; Jiang Wali
- 刊名：Seismology and Geology
- 出版年：2012
- 卷期：34(1)
- 关键词：古地震 ; paleoearthquakes ; 山西 ; Shanxi Province
- 页码：p.76-92
- 图表：7 illus., 2 tables, 15 refs.
- 分类号：0500
- issnNo：ISSN0253-4967
- isbnNo：CN11-2192/P
摘要
Several trenches were excavated in the previous work along the Jiaocheng Fault zone,which revealed three paleoearthquake events.But the northern boundary of the Jiaocheng Fault zone cannot be confirmed by the previous studies.The paper discussed the fault activities revealed in the three trenches excavated in the northern and central Jiaocheng Fault.Among them,Longwanggou trench is a combination which includes several trenches excavated in western Nitun Basin,Yangqu County.The paper introduced the trench profiles which cross the two right-stepped faults.As is shown in Longwanggou trench,the range of Holocene activity of the Jiaocheng Fault is extended 20km northward.The Wayaogou and Xinmin trenches are located in the central segment of the fault.One is at the foreplatform margin on the east of Wayaogou.The other is in front of the terrace T1 on the west of Shierkougou.Loam and mud layers of mid Holocene(with 14C ages of 5 ～ 6ka BP) and multi-parallel fault planes were observed in all the three trenches.In conclusion,the three Holocene faulting events as revealed in the three trenches are synchronous,which is consistent with previous trenching results.The time of the three events is 3.06 ～ 3.53ka,about 5.32ka or 6.14ka,and about 8.36ka B.P.The recurrence interval of the three events is about 2.02 ～ 2.84ka and about 3.04 ～ 2.22ka.The coseismic vertical displacement of these events is 1.5 ～ 4.7m,which shows surface faulting earthquake activity with magnitude greater than 7.0.This paper concludes with a discussion of the effect of 14C dating samples collected from the trenches.