新增玉屏潜源对湘黔边界地区峰值加速度影响的研究

Research on the influence of PGA when considering the new Yuping potential seismic source in the Hunan-Guizhou border region

本文收集了怀化西部新增玉屏潜在震源区相关资料,对研究区域1′×1′的空间格点进行了地震危险性概率分析,主要讨论了在新增该潜源前、后对湘黔边界地区的峰值加速度的变化,并根据Ⅱ类场地峰值加速度绘制等值线并进行分区。地震危险性分析结果表明,新增玉屏潜源对其内部与附近约20 km范围的地震动峰值加速度影响很大,而当震源深度取10 km时,玉屏潜源范围内50年10%的峰值加速度由35~40 cm/s^(2)增加至80~95 cm/s^(2),约增加2.3~2.4倍,潜源内新晃、芷江等局部区域基本烈度可达Ⅶ度,潜源外部峰值加速度也从35 cm/s^(2)逐渐增加至80 cm/s^(2);当地震带的震源深度取15 km时,新晃、芷江等地区基本烈度仍为Ⅵ度。文中还结合怀化西部新晃、芷江不同类型房屋的抗震能力进行了初步分析,在后续防震减灾工作中需特别加以关注。

This paper collects relevant information on the newly added Yuping potential seismic source in western Huaihua,and analyzed the seismic hazard of the study area based on 1′×1′grid points.We mainly discussed the changes in PGA before and after the new potential seismic source in the Hunan-Guizhou border region,and drawing isolines and zoning based on the PGA of siteⅡ.The results of seismic hazard analysis show that the PGA has been greatly improved inside and 20 km away around the new potential seismic source.When the focal depth is 10 km,the PGA of exceeding probability of 10 in 50 years within the Yuping potential source range increases from 35~40 cm/s^(2) to 80~95 cm/s^(2),increase of about 2.3 to 2.4 times.In local areas such as Xinhuang and Zhijiang within the potential source,the basic intensity can reachⅦdegrees.And outside the potential source,PGA gradually increases from 35~80 cm/s^(2).When the focal depth is 15 km,the basic intensity in regions such as Xinhuang and Zhijiang remains atⅥdegrees.The article also conducted a preliminary analysis of the seismic capacity of different types of houses in Xinhuang and Zhijiang county in western Huaihua.Additional attention should be paid to the follow-up work of earthquake prevention and disaster reduction.