云南曲靖-昭通断裂带北段晚第四纪以来的古地震
|
摘要
<正> 一、前言云南曲靖-昭通断裂带北段南起昭通盆地,北止玛瑙以北,全长180km。该断裂带自南向北主要由大关口断裂、中坝断裂、高桥断裂、大毛滩断裂、玛瑙断裂和利店断裂组成。另外还有NE向的洒鱼河断裂、新田断裂及EW向的木杆河断裂与之
Based on field investigation and trench excavation, many paleoseismic relics have been identified and studied along the northern part of Qujing-Zhaotong Fault, Yunnan Province. The geological and morphologic features of the relics include seismic faults, colluvial wedges, fault scarplets, seismic landslide masses, as well as paleoseismic liquefaction. These features reveal the fault segmentation and their levels of activities. Three Holocene paleoearthquakes have been recognized from fault scarplets and drainage offsets near Zhongbacun village. Along Damaotan fault segment, which is the most active segment of the northern part, paleoseismic relics typically appear from which 7 paleo-events are identified. Three of the 7 events occurred in Holocene, probably greater than magnitude 7. The recurrence interval of paleo-earthquakes in the early-to-mid Holocene is estimated as about 3 ka. However, the interval between the 1974 Yongshan earthquake and the 1844 Yuanheng earthquake was just 130 years. Does the recurrence interval tend to be shorter? Anyhow, from available data, we conclude that Damaotan and Zhongba segments have been more active than Daguankou and Gaoqiao segments in Holocene.
Based on field investigation and trench excavation, many paleoseismic relics have been identified and studied along the northern part of Qujing-Zhaotong Fault, Yunnan Province. The geological and morphologic features of the relics include seismic faults, colluvial wedges, fault scarplets, seismic landslide masses, as well as paleoseismic liquefaction. These features reveal the fault segmentation and their levels of activities. Three Holocene paleoearthquakes have been recognized from fault scarplets and drainage offsets near Zhongbacun village. Along Damaotan fault segment, which is the most active segment of the northern part, paleoseismic relics typically appear from which 7 paleo-events are identified. Three of the 7 events occurred in Holocene, probably greater than magnitude 7. The recurrence interval of paleo-earthquakes in the early-to-mid Holocene is estimated as about 3 ka. However, the interval between the 1974 Yongshan earthquake and the 1844 Yuanheng earthquake was just 130 years. Does the recurrence interval tend to be shorter? Anyhow, from available data, we conclude that Damaotan and Zhongba segments have been more active than Daguankou and Gaoqiao segments in Holocene.
引文
[1] 侯治华,曲靖-昭通断裂北段晚第四纪活动特征,地壳构造与地壳应力文集(11) ,北京:地震出版 社,1999。
[2] 侯治华,1844年大关北地震问题的探讨,地球物理进展,Vol.14,No.1,1999。
[3] 朱海之,从昭通地震破坏实例看山区地震地面破坏特点,地质科学No.3,1975。
[2] 侯治华,1844年大关北地震问题的探讨,地球物理进展,Vol.14,No.1,1999。
[3] 朱海之,从昭通地震破坏实例看山区地震地面破坏特点,地质科学No.3,1975。
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心