Abstract: Three typical strong seismic regions, Tangshan, Xingtai and Zhangbei, are located within 300 km radius around the Xiong'an New Area in northern China. The Xingtai M 7.2 earthquake in 1966, Tangshan M 7.8 earthquake in 1976, and Zhangbei M 6.2 earthquake in 1998 had occurred in the past 50 years and future risks of earthquake destruction in the region still exist. Under the present tectonic stress environment, what are the fault activity hazards in these three regions and how do moderate-strong earthquakes affect ground stability of the Xiong'an New Area? To answer these questions, we first calculated the critical failure state of the main potential seismogenic faults based on the hydraulic fracturing in-situ stress measurements in deep wells in the three areas, using Byerlee's fault slip friction criterion, and then investigated the fault activity hazards. Next, we determined the potential main earthquake source regions within 300 km radius of the Xiong'an New Area and the maximum earthquake magnitude for each source region, according to the fifth generation seismic ground motion parameters zonation map as well as potential source regions zonation map of China. Finally, we used the appropriate seismic intensity attenuation model to quantitatively calculate the seismic intensity attenuation in the Xiong'an New Area from the three strong seismic areas, providing some scientific guidelines for seismic fortification of major projects in the Xiong'an New Area. The results show that (1) if potential maximum magnitude earthquakes occur in the three strong earthquake regions, the attenuation of seismic intensity in the Xiong'an New Area will vary between Ⅳ and Ⅶ degrees; (2) the potential M 8.0 earthquake in the Tongzhou district of Beijing, or M 6.5 earthquake along the Laishui-Gaobeidian of Baoding, will generate Ⅶ degrees of intensity attenuation in the Xiong'an New Area, which may result in minor earthquake damage; (3) the attenuation of seismic intensity produced by other potential seismic source areas will be less than V degrees, causing no significant seismic damage in the Xiong'an New Area. Therefore, the seismic fortification intensity of the Xiong'an New Area is recommended to be adjusted from the original Ⅶ degrees to Ⅷ degrees.

Key words: strong seismic regions of northern China, active fault zone, in situ stress, seismic activity, Xiong'an New Area