Slip rate and recurrence intervals of the east Lenglongling fault constrained by morphotectonics: Tectonic implications for the northeastern Tibetan Plateau
Slip rate and recurrence intervals of the east Lenglongling fault constrained by morphotectonics: Tectonic implications for the northeastern Tibetan Plateau
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DOI：
10.1130/l597.1
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发表时间：
2017-06-01
期刊：
影响因子：
2.4
通讯作者：
Tian, Yunfeng
中科院分区：
文献类型：
--
作者：
Jiang, Wenliang;Han, Zhujun;Tian, Yunfeng
青藏高原东北缘的冷龙岭断裂对青藏高原的构造变形起着重要的调节作用，其北邻戈壁-阿拉山地台，东邻华北克拉通。然而，由于缺乏以前的研究，对该故障知之甚少。本研究利用高分辨率遥感影像结合陆地光探测和测距（LiDAR）数据，对冷龙岭断裂带东段的错动地貌进行了调查。微地形分析保存完好的偏移阶地，冲沟，山脊，洪积扇在高原环境允许单事件滑动和多事件累积slipp.Our研究提供了一个重要的评估水平偏移与最近的地震和四个古地震，确定了一系列的偏移基岩阶地，通过构建一个morphoteconstructionevolution model。地面LiDAR数据表明，冷龙岭东断裂遵循特征滑动模式。该剖面的单次滑动量约为9.4 m，全新世期间发生过7-8次古地震，左旋走滑速率为6.6 ± 0.3 mm/a，结合单次滑动量的分布，确定了冷龙岭东断裂沿着过去地震的平均复发间隔为1430 ± 140年。这一结果与相邻的古浪断裂相似，但与相邻的其他断裂略有不同，这可能意味着冷龙岭断裂和古浪断裂组成了一个完整的断裂带。该地区存在大量千年一遇的活动断裂，增加了青藏高原东北部未来地震活动的风险。
The Lenglongling fault located in the northeast margin of the Tibetan Plateau plays an important role in accommodating the tectonic deformation of the Tibetan Plateau relative to the Gobi-Ala Shan platform to the north and the North China craton to the east. However, little is known about the fault due to a lack of previous research. In this study we use terrestrial light detection and ranging (LiDAR) data combined with high-resolution remote sensing images to survey offset landforms in the east part of the Lenglongling fault. Microtopographic analysis of well-preserved offset terraces, gullies, ridges, and pluvial fans in the highland environment allows evaluation of single-event slip and multievent cumulative slip.Our study provides an important assessment of the horizontal offset associated with the latest earthquake and four paleoearthquakes that were identified from a series of offset bedrock terraces by constructing a morphotectonic evolution model. Terrestrial LiDAR data indicate that the east Lenglongling fault follows a characteristic slip model. The single-event slip of this section is similar to 9.4 m; 7-8 paleoearthquakes are thought to have occurred during the Holocene, and a left-lateral strike-slip rate of 6.6 +/- 0.3 mm/yr is estimated.Combining the slip rate and the single-event slip distribution, we determine a mean recurrence interval of 1430 +/- 140 yr for past earthquakes along the east Lenglongling fault. This result is similar to that of the adjacent Gulang fault, but differs slightly from those of other adjacent faults, which may mean that the Lenglongling and Gulang faults compose an integral fault zone. The large number of millennial recurrent active faults in this region heightens the risk of future seismic activity in the northeast Tibetan Plateau.