濑溪河流域地貌对泸县M_(S)6.0地震发震构造变形的响应及其指示作用  

Response of the topography of Laixihe drainage to the structural deformation induced by M_(S)6.0 Luxian earthquake and its indication

作　　者：周文英 梁明剑[1] 左洪 廖程 吴微微[1] 王明明[1] 宫悦[1] 魏娅玲[1] Zhou Wenying;Liang Mingjian;Zuo Hong;Liao Cheng;Wu Weiwei;Wang Mingming;Gong Yue;Wei Yaling(Sichuan Earthquake Agency,Chengdu 610041,China)

机构地区：[1]四川省地震局,中国成都610041

出　　处：《地震学报》2022年第2期250-259,共10页Acta Seismologica Sinica

基　　金：中国地震局地震科技星火计划(XH202302);四川省地震局地震科技专项(LY2216);国家重点研发计划(2020YFA0710600);四川省地震局地震科技创新团队专项(201804);西藏拉萨地球物理国家野外科学观测站研究课题(NORSLS21-04)共同资助.

摘　　要：以12.5 m数字高程模型数据为基础,采用数字地貌分析方法提取了濑溪河流域的高程剖面和面积-高程积分(HI)等地貌参数,分析了2021年9月16日四川盆地东南部泸县M_(S)6.0地震震中附近区域地貌与构造活动的响应关系。结果显示:震中西侧的螺观山和梯子崖背斜在震中的南北两端存在明显的缩短量差异;HI条带状低值区的展布方向与流域内构造的方向一致,HI高值区位于华蓥山两条断裂夹持的谷地,但在震中附近存在WNW向的HI低值带。综合分析认为,泸县地震震中附近应存在一走向为WNW的隐伏构造,它不仅调节了螺观山和梯子崖背斜在震中南北两端的缩短量差异,也使得HI值受其影响呈低值特征,该结果与震源机制解结果、等震线长轴走向以及余震空间展布的优势方向相一致。Based on 12.5 m DEM data,the elevation profile and hypsometric integral(HI)of Laixihe drainage are extracted by digital geomorphological analysis method,and the response relationship between geomorphology and tectonic activity in the areas near the epicenter of Luxian M_(S)6.0 earthquake is analyzed.The results show that the Luoguanshan and Tiziya anti-clines have obvious shortening differences between the north and south ends of the epicenter.The low HI value zone is consistent with the direction of the structure in the basin.The high HI value zone is located between the valleys clamped by the two faults of Huayingshan,but there is a low value zone in WNW direction near the epicenter.The comprehensive analysis shows that there should be a WNW-trending buried structure near the epicenter,which not only regu-lates the shortening difference between the north and south ends of the epicenter for the Luoguanshan and Tiziya anticlines,but also makes the HI value being a low value charac-teristic affected by it.The WNW direction of the buried structure is consistent with the results of the focal mechanism solution,major axis strike of isoseismal line,and the dominant predirec-tion of spatial distribution of aftershocks.

关 键 词：泸县 M_(S)6.0 地震 发震构造 华蓥山断裂带 濑溪河 流域面积-高程积分 

分 类 号：P315.2[天文地球—地震学]