LATE QUATERNARY PALEOEARTHQUAKES ON THE MIDDLE SEGMENT OF THE LIJIANG-XIAOJINHE FAULT, SOUTHEASTERN TIBET

被引：0
|
作者：
Ding R. [1 ,2 ]
Ren J.-J. [1 ]
Zhang S.-M. [1 ]
Lü Y.-W. [1 ]
Liu H.-Y. [1 ]
机构：
[1] Key Laboratory of Crustal Dynamics, Institute of Crustal Dynamics, China Earthquake Administration, Beijing
[2] State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing
来源：
Dizhen Dizhi | 2018年 / 40卷 / 03期
关键词：
Lijiang-Xiaojinhe Fault; Paleoearthquake; Recurrence interval; Sichuan-Yunnan block; Trench;
D O I：
10.3969/j.issn.0253-4967.2018.03.009
中图分类号：
学科分类号：
摘要：
More attention has been paid to the late Quaternary activity of the boundary fault of the Sichuan-Yunnan block in eastern Tibet. The Lijiang-Xiaojinhe Fault (LXF) locates along the boundary of the northwest Sichuan and central Yunnan sub-blocks in the Sichuan-Yunnan block. Clear displaced landforms show that the fault has undergone strong late-Quaternary activity. However there is no surface-rupturing earthquake occurring on the LXF in the historical record. The LXF crosses the city of Lijiang, one of the most important tourist cities in Southwest China. The rupture behavior on this fault remains unclear and it is hard to assess its seismic hazard in the future. In this study, on the base of the interpretation of high-resolution satellite imagery, we chose the middle segment of the LXF and dug three trenches at Muzhuda, Hongxing, and Gantangzi sites to constrain the ages of paleoearthquakes combined with radiocarbon dating and OxCal modeling. The Muzhuda trench shows that at least three events occurred on the middle segment of the LXF at 7940~6540a BP, 4740~4050a BP and 1830~420a BP, respectively. The Hongxing trench indicates that the LXF underwent two events at 5120~3200a BP and 2100~1220a BP. The Gantangzi trench reveals at least three paleoearthquakes at 44980~17660a BP, 7210~3810a BP and 2540~1540a BP, respectively. The events in the Gantangzi trench might be incomplete because of stratigraphic gap. These three trenches indicate that three events occurred on the middle segment of the LXF in the Holocene at 7940~7210a BP, 4740~4050a BP and 1830~1540a BP, respectively. Large earthquakes on the middle segment of the LXF appear to fit the quasi-periodic model with the mean recurrence interval of ~3 000a and the estimated magnitude 7.5. Given the strong late-Quaternary activity of the middle segment of the LXF and a long elapsed time, we propose that the middle segment of the LXF might have a high seismic hazard potential in the near future. © 2018, Editorial Office of Seismology and Geology. All right reserved.
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页码：622 / 640
页数：18
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