关键词: 断裂活动性, 安丘-莒县断裂, 安丘—朱里段, 安丘7级地震

Abstract: The Yishu Fault zone is a part of the Tanlu Fault zone that passes through Shandong Province and the northern area of Jiangsu. It is composed of 5 nearly parallel faults among which the Anqiu-Juxian Fault is the most important and prominent active fault since late Pleistocene and is usually considered to be the seismogenic fault of the 70 BC M 7 Anqiu earthquake and the 1668 AD M 8¹/₂ Tancheng earthquake. By detailed research in recent years, e.g. the active fault mapping implemented during the “Eighth Five-Year Plan” period, we have gained thorough knowledge of the middle segment of the Anqiu-Juxian Fault to the south of Juxian, while the knowledge of the segment to the north of Juxian has been poor, even no active fault profiles have ever been found. Recent discoveries about the geometry and activity of the Anqiu-Zhuli segment of the Anqiu-Juxian Fault are introduced in this paper. The segment consists of the Nanliu sub-segment, the Shuangguan-Meicun sub-segment and the Zhuli sub-segment. All these sub-segments are distributed along the linear boundary line between hilly area and plain, or locate in the eastern slope of the NNE-trending hills. These fault segments are featured with right-lateral strike-slip movement combined with dip component, and their latest activity age is late Pleistocene to early Holocene. In conclusion, The Anqiu-Juxian Fault is the predominant active structure between Juxian and Changyi in the north of Shandong, and it should have some connections with the occurrence of the 70 BC M 7 Anqiu earthquake. Since the elapsed time is nearly 2100 years, the future earthquake risk in this area shall be emphasized.

Key words: fault activity, Anqiu-Juxian Fault, Anqiu-Zhuli segment, the M 7 Anqiu earthquake