大毛滩活动断裂晚第四纪活以来的古地强震研究
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摘要
根据对云南曲靖—昭通断裂带北段的大毛滩断裂上多次野外地震地质调查和探槽揭露,发现有较多的古地震遗迹,如地震断层陡坎、崩塌体、地震沟槽、堰塞塘和断裂崩积楔等。主要分布于大毛滩断裂的纸厂坝、苏田坝、大毛滩和六马场地区和木杆河断裂的手扒岩、马家坪一带。 该区晚更新世晚期至全新世以前,曾发生过四次古地震事件,地震时间间隔为 4000—7000 年;距今5000--10000 年,发生过两次古地震,时间间隔为1500—2000 年,从5000 年至有历史记载的公元 1216马湖地震,古地震的时间间隔可能是 1000—1600年(不计田坝、丁木、李子湾事件);自公元 1216 年到现今的 782 年间,共发生了四次强烈地震,平均时间间隔为 195年,但从1844年以后,地震的时间间隔为 73—57年。可以看出自公元1216年以来,该区的地震时间间隔在大大地缩短。
On the basis of field investigation and trench excavation, many pale seismic relics have been identified along the Damaotan Fault. The geological and morphologic features of pale earthquake mainly include seismic fault, colloidal wedge, fault scarp, seismic landslide mass, as well as pale seismic liquefaction. These features reveal the segmentation and the most active segment, which is the Damaotan fault, of this part. We have identified the following pale seismic events along the Damaotan segments: 7 pale earthquakes, greater than 7.1 Richter Scale, 3 of which occurred in Holocene. The recurrence interval of pale earthquakes of early to middle Holocene was about 3ka. The interval between 1974 Yongshan earthquake and the 1844 Yuanheng earthquake was 130a. The recurrence interval tends to be shorter. The Damaotan segments are more active than the Qingangzhui and Lumachang and Damaotan and Yuanheng segments during Holocene.
On the basis of field investigation and trench excavation, many pale seismic relics have been identified along the Damaotan Fault. The geological and morphologic features of pale earthquake mainly include seismic fault, colloidal wedge, fault scarp, seismic landslide mass, as well as pale seismic liquefaction. These features reveal the segmentation and the most active segment, which is the Damaotan fault, of this part. We have identified the following pale seismic events along the Damaotan segments: 7 pale earthquakes, greater than 7.1 Richter Scale, 3 of which occurred in Holocene. The recurrence interval of pale earthquakes of early to middle Holocene was about 3ka. The interval between 1974 Yongshan earthquake and the 1844 Yuanheng earthquake was 130a. The recurrence interval tends to be shorter. The Damaotan segments are more active than the Qingangzhui and Lumachang and Damaotan and Yuanheng segments during Holocene.
引文
[1]侯治华.曲靖—昭通断裂北段晚第四纪活动特征[M].地壳构造与地壳应力文集.北京:地震出版社.1999
[2]侯治华.1844年大关北地震问题的探讨[J].地球物理进展,1999,14(1),63-65
[3]朱海之.从昭通地震破坏实例看山区地震地面破坏特点[J].地质科学,1975.(3)32-33
[2]侯治华.1844年大关北地震问题的探讨[J].地球物理进展,1999,14(1),63-65
[3]朱海之.从昭通地震破坏实例看山区地震地面破坏特点[J].地质科学,1975.(3)32-33
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