| 地貌参数指示的临潭-宕昌断裂带最新构造隆升差异与地震活动 |
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| 摘 要： | 2013年7月22日,甘肃岷县漳县MS6.6地震发生在青藏高原东北缘的临潭-宕昌断裂带上。为了研究该断裂的最新构造隆升的差异性,基于ASTER GDEM数字高程模型数据提取了流域盆地及水系,并以此为基础,计算了面积高程积分及河道坡度指数。2个地貌参数的分析结果表明,临潭-宕昌断裂不同部位的最新隆升呈现不均匀性。其中,断裂的最新逆冲活动在临潭以西及以岷县附近明显强于其他各段。上述地貌参数所指示的断裂抬升强度还与历史及现今地震发震位置较好地匹配,体现了定量化地貌分析对断裂活动强弱的指示作用。临潭-宕昌断裂受区域NE-SW向挤压构造应力作用影响,其活动的差异可能与晚第四纪以来巴颜喀拉块体NE向扩展背景下的局部应力集中有关。
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| 收稿时间： | 24 September 2013 |
GEOMORPHIC INDICES INDICATED RECENT DIFFERENTIAL TECTONIC UPLIFT OF THE LINTAN-DANGCHANG FAULT AND THE MINXIAN-ZHANGXIAN EARTHQUAKE |
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| Authors: | GAO Ming-xing CHEN Gui-hua XU Xi-wei |
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| Institution: | 1.Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China;2.Earth Observatory of Singapore, Nanyang Technological University, Singapore 639798 |
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| Abstract: | The July, 22, 2013 MS6.6 Minxian-Zhangxian earthquake occurred in the Lintan-Dangchang Fault belt which is located in the northeast Tibet Plateau. Recent tectonic activities show that the Lintan-Dangchang Fault is a thrust fault with strike-slip component. However, the spatial pattern and mechanism of the recent tectonic activity along this fault have not been analysed in detail before the occurrence of the Minxian-Zhangxian earthquake. For better understanding the differential recent tectonic uplift of this fault, drainage basins and river networks were extracted based on ASTER GDEM data in this study. Hypsometric integral and the stream length gradient were calculated. The geomorphic indices analysis results suggest the differential tectonic uplift along the Lintan-Dangchang Fault. The areas experiencing strong tectonic uplift were identified which locate at the west of the Lintan County and around Minxian County. Besides, high geomorphic indices values are associated with epicenters of the historical earthquakes, which demonstrates the importance of the quantitative geomorphic analysis. Our results suggest that the overall tectonic uplift along the Lintan-Dangchang Fault is not very strong. However, certain segments which are experiencing relative high tectonic uplift have the potential of generating moderate or even large earthquakes. Under the regional NE-SW compressional stress caused by the northeastward expansion of the Bayankala block, the tectonic uplift of the fault may relate to the local stress concentration. |
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| Keywords: | Minxian-Zhangxian earthquake Lintan-Dangchang Fault DEM tectonic geomorphology |
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