虎跳峡地区新生代以来应力场演化及断裂新活动性探讨

本文通过对虎跳峡地区的实地调查、区域地质图的详判、断层擦痕矢量解和震源机制解等综合分析，探讨了研究区新生代以来区域构造应力场的演化，并对研究区的主要断裂活动性进行了分析。研究结果表明，新生代以来区域应力场的演化次序为早第三纪东西向、中新世近南北向、上新世北西向、早更新世北北东向、中更新世早期近东西向以及晚更新世以来北北西向多期应力场；区内北西向中甸—永胜断裂的新活动性强，其次是丽江—小金河断裂，楚波—白汉场断裂活动性较弱。

THE STUDY OF THE EVOLUTION OF NEOTECTONIC STRESS FIELDS AND REACTIVITIES OF THE MAIN DEEP FRACTURES IN HUTIAOXIA REGION

Based on the investigation of the field, analysis of the large scaled geological maps, the focal mechanism solutions and Rn measurements, the evolution of the stress field and the activities of the main fractures in Hutiaoxia (Tiger leaping gorge) region, northwest of Yunnan province in the present paper are discussed. It is suggested that the sequence of the evolution of the stress field in Cenozoic is E W (Eogene), nearly S N (End of Miocene), NW SE ( Pliocene), NNE SSW (early Pleistocene), E W ( End of early Pleistocene early middle Pleistocene), NNW SSE (since late Pleistocene). Zhongdian Yongsheng fracture is most active, while Lijiang Xiaojinhe fracture is active and Chubo Baihanchang fracture is less active.