中国大陆7级以上地震频次场与应变场对比研究

Comparative Study on the Frequency Field and Strain Field of Earthquakes above Magnitude 7 in Chinese Mainland

摘要: 本文应用自然正交函数展开方法，分别研究1980~2020年中国大陆7级以上地震应变场和频次场的时间因子变化特征。结果表明大震前时间因子在平稳背景上会出现超过均方差突跳上升或突跳下降异常变化，异常主要集中在前4个场，大震前均出现中长期异常，部分出现短临异常特征。最后对比研究频次场与应变场的时间因子异常的差异性，为大震预测提供依据。

Abstract: In this paper, the natural orthogonal function expansion method is applied to respectively study the time factor variation characteristics of the strain field and frequency field of earthquakes above magnitude 7 in Chinese mainland from 1980 to 2020. The results show that before a major earthquake, the time factor will exhibit abnormal changes such as a sudden increase or decrease beyond the mean square error on a stable background. The anomalies are mainly concentrated in the first four fields, and all of them show medium- and long-term anomalies before the major earthquake, with some showing short-term and imminent anomaly characteristics. Finally, the differences in the time factor anomalies of the frequency field and the strain field are compared and studied to provide a basis for major earthquake prediction.