新疆北天山中东段呼图壁地区震源深度的重新测定  

Redetermination of Focal Depth in Hutubi Region of the Middle and East of North Tianshan in Xinjiang

作　　者：李艳永[1] 唐明帅[1] 乌尼尔[1] Li Yanyong;Tang Mingshuai;Wu Nier(Earthquake Agency of Xinjiang Uygur Autonomous Region,Urumqi 830011,China)

机构地区：[1]新疆维吾尔自治区地震局

出　　处：《震灾防御技术》2019年第2期352-362,共11页Technology for Earthquake Disaster Prevention

基　　金：新疆地震科学基金(201708、201712);国家自然科学基金(41574088);新疆自治区自然科学基金(2016D01A061);新疆自治区科技人才培养项目(QN2016YX0433);中国地震局“三结合”课题(CEA-JC/3JH-17310、3JH-201901016);地震科技星火计划项目(XH18055)

摘　　要：联合Hyposat法、PTD法和g CAP矩张量反演法,重新测定新疆北天山中东段呼图壁地区2010-2017年502个地震的震源深度,并对震源深度剖面进行初步分析。结果表明,重新测定的震源深度优势分布为15-20km,平均震源深度为16km,呼图壁MS 6.2地震的震源深度为20km;研究区南部和中部的震源深度集中分布在20km左右,与北天山壳内低速体的层位相当,可能是上地壳和下地壳之间的韧性剪切带存在的部位,起到滑脱层的作用,研究区北部的震源深度则向浅部扩展;呼图壁MS6.2地震的发震断裂可能在清水河子断裂下方的1条隐伏反冲断层上,可能是霍尔果斯断裂向前沿断坡冲断受阻而在相反方向上发育分支反冲断层的结果。Combined with Hyposat method, PTD method and g CAP moment tensor inversion method, the focal depth of 502 earthquakes in Hutubi region during 2010—2017 are re-determined, and the focal depth profile is preliminarily analyzed. The results show that the dominant distribution of focal depth is 15—20 km, the average focal depth is 16 km, and the focal depth of Hutubi MS 6.2 earthquake is 20 km. The focal depth in the southern and central regions of the study area is concentrated around 20 km, the depth is similar to that of the low velocity layer in the 20 km crust of the North Tianshan Mountains, which may be the ductile shear zone between the upper crust and the lower crust. The location of the shear zone acts as a slip layer, and the focal depth in the northern part of the study area extends to the shallow part. The causative fault of the Hutubi MS 6.2 earthquake may be on a hidden recoil fault beneath the Qingshuihezi fault and may be the result of the thrust of the Horgos fault to the front slope and the development of the branch recoil fault in the opposite direction.

关 键 词：呼图壁地区 震源深度 Hyposat方法 PTD方法 gCAP矩张量反演法 

分 类 号：P315.33[天文地球—地震学]