GPS水平形变面应变率梯度与强震危险区关系探讨

Relationship between plane strain rate gradient of GPS horizontal deformation and strong earthquake risk area

全球定位系统(GPS)观测和信息处理技术的发展,为获取高精度地壳水平运动和相关的应用研究提供了良好的基础.应用中国地壳运动观测网络中心提供的1999—2007年GPS水平形变速率观测结果,研究了地壳水平形变面应变率梯度与强震发生的关系,探索了地震中长期预测对强震危险区的判识方法.结果表明,中国大陆2001—2011年发生的大部分MS6.8以上强震,地震地点均位于面应变梯度高-低值过渡区与块体边界带相交汇的部位;GPS面应变率梯度可以作为中长期强震危险区判识的一种方法,与最大剪应变率分布相比,缩小了强震孕育地点的判识范围.文章最后给出了中国大陆地区未来10年或稍长时间的强震危险区.

Rapid development of GPS observation and information processing techniques has provided a solid foundation for acquiring accurate horizontal crustal motion and related researches. In this paper, by using the horizontal de- formation rate of GPS observation from 1997 to 2007, which was provided by Crustal Movement Observation Network of China, the relationship between plane strain rate gradient and strong earthquake risk area is discussed, and iden- tifying method of mid-long term prediction of strong earthquake risk area is ex- plored. The results show that from 2001 to 2011 most Ms〉/6.8 earthquakes occurred in Chinese mainland are in the high-tow transmo- ~ e gradient and its intersection parts with the block boundary zone. GPS plane strain rate gradient can be used as a method for identifying strong earthquake risk area for mid-long term prediction by comparing the observed strain rate with the maximum shear strain rate. By using this method the judgment range of locations of strong earthquakes could be reduced. Finally, we pointed out the strong earthquake risk areas for the next 10 years or longer period.