关键词: 岷江断裂, 古堰塞湖, 全新世, 古地震

Abstract: During the post-disaster recovery in Maoxian country,we found that lacustrine sediments are exposed intermittently ～30km north of the present Diexi barrier lake(Xiaohaizi)along the Minjiang River and its tributaries.According to the study on lacustrine sediments around Qiangyang village,we obtained the evidence of activities of the Minjiang Fault in the Holocene.It is concluded that the tectonic deformation of paleo-lacustrine sediments in Qiangyang possibly reflects multi-time ancient seismic activity of Minjiang Fault zone.It is more accepted that the 1st seismic activity resulted in the formation of dammed paleolake in Qiangyang,and accumulation of the 1st set of lacustrine facies deposits;the 2nd seismic activity led to deformation of the lacustrine facies stratum;the 3rd seismic activity caused the deformation of the 1st and 2nd set of lacustrine facies strata;and the 4th seismic activity ruptured the youngest deposit overlying the lacustrine facies stratum.Total Station Instrument measurements indicate that the vertical displacement of the last ancient seismic activity is about 2.6～3.6m.

Key words: Minjiang Fault, paleo-dammed lake, the Holocene, paleoearthquake