摘要
佛洞庙-红崖子断裂位于祁连山北缘断裂带中段,是1条活动逆断裂。在佛洞庙-红崖子断裂东、中、西各段落开挖整理了5个探槽。通过探槽揭示的各地层单元的沉积特征、各单元之间的层序关系以及断层对不同地层的切割关系,共辨认出了4次古地震事件。根据探槽中各地层单元的14C样品和光释光样品测年结果,对4次古地震事件给出了年龄制约:最早事件E4发生在距今约10.6ka,事件E3发生在距今约7.1ka,事件E2发生在距今约3.4ka,事件E1为1609年红崖堡地震。这4次地震事件的间隔分别约3.5ka、3.7ka和3.0ka,平均复发间隔约3.4ka,具有准周期重复特征。
The Fodongmiao-Hongyazi Fault is a Holocene active thrust fault,belonging to the middle segment of northern Qilianshan overthrust fault zone,located in the northeastern edge of the Tibet plateau.The Hongyapu M7 1/4 earthquake in 1609￣￣AD occurred on it.A few paleo-seismology studies were carried out on this fault zone.It was considered that four paleoearthquakes occurred on the Fodongmiao-Hongyazi Fault between(6.3±0.6)ka￣￣BP and(7.4±0.4)ka￣￣BP,in(4.3±0.3)ka￣￣BP,in(2.1±0.1)ka￣￣BP and in 1609￣￣AD.The occurrences of the earthquakes suggested the quasi-periodic characteristic with a quasi-periodic recurrence interval between 1￣￣600~2￣￣500a(Institute of Geology,State Seismological Bureau,Lanzhou Institute of Seismology,State Seismological Bureau.1993;Liu et al.,2014).There was no direct evidence for the Hongyapu M7 1/4 earthquake in 1609￣￣AD from trench research in the previous studies.Great uncertainty exists because of the small number of the chronology data,as a few TL and OSL measurement data and several\{14 C\}data,and it was insufficient to deduce the exact recurrence interval for the paleoearthquakes.Five trenches were excavated and cleared up respectively in the eastern segment,middle segment and western segment along the Fodongmiao-Hongyazi Fault.After detail study on the trench profiles,the sedimentary characteristics,sequence relationship of the stratigraphical units,and fault-cuts in different stratigraphical units were revealed in these five trenches.Four paleoearthquakes in Holocene were distinguished from the five trenches,and geology evidences of the Hongyapu M7 1/4 earthquake in 1609￣￣AD were also found.More accurate constraint of the occurring time of the paleo-earthquakes since Holocene on the Fodongmiao-Hongyazi Fault is provided by the progressive constraining method(Mao and Zhang,1995),according to amounts of\{14 C\}measurement data and OLS measurement data of the chronology samples from different stratigraphical units in the trenches.The first paleoev
作者
黄雄南
杨晓平
杨海波
HUANG Xiong-nan;YANG Xiao-ping;YANG Hai-bo(Key Laboratory of Active Tectonics and Volcano,Institute of Geology, China Earthquake Administration,Beijing 100029,China)
出处
《地震地质》
EI
CSCD
北大核心
2018年第4期753-772,共20页
Seismology and Geology
基金
中国地震活动断层探察:南北地震带北段项目(20140823)和国家自然科学基金(41572195)共同资助。
关键词
古地震
佛洞庙-红崖子断裂
祁连山北缘
paleoearthquake
Fodongmiao-Hongyazi Fault
Northern Qilianshan
