关键词: 沂沭断裂带, SBAS-InSAR, 负位错模型, 断层闭锁, 滑动亏损

Abstract: In this paper, the Sentinel-1A data covering 60 scenes of the Yishu fault zone from October 2022 to April 2023 are used to obtain large-scale surface LOS deformation results by SBAS-InSAR technology, and the InSAR deformation field is down-sampled.Then, based on the negative dislocation model, TDEFNODE software is used to calculate the fault locking degree and slip loss distribution of Yishu fault zone, and combined with the temporal and spatial distribution of earthquakes, the movement characteristics of fault plane are described in detail, and the segmental seismic risk of the fault is quantitatively determined. The results show that the fault locking degree is high and the locking depth is deep in the area north of Anqiu in the northern segment of Ju county fault, the maximum locking depth is about 26°, and the fault locking is weak in the segment from Anqiu to Tancheng, which is basically in creep slip state.The area north of Anqiu in Yishu fault zone has a dextral slip loss rate of 0.5～1.5 mm/a, which is the unruptured segment of 1668 Tancheng earthquake. It has the characteristics of seismicity gap and is easy to accumulate stress. The seismic risk of this segment deserves attention.Compared with the previous studies, it is found that the locking degree of the section north of Tancheng in Yishu fault zone is weakened, which is mainly related to the influence of Miyagi Mw9.0 earthquake on March 11,2011. The occurrence of Japan earthquake plays a certain role in relieving the westward subduction and compression of Pacific plate, resulting in the change of regional stress-strain field of Tanlu fault zone.

Key words: Yishu fault zone, SBAS-InSAR, keywords negative dislocation model, fault locking, slip loss