地磁低点位移法是20世纪提出的地震短临预测方法，该方法通过研究每日中国大陆地磁低点时间变化特征，给出地震短临预测意见，但不足之处是其仅研究了地磁日变化畸变的时间特征，未研究畸变幅度，因此虚报率高。本文通过分析低点位移线两侧台站地磁日变化的相关性，研究了地磁低点位移异常畸变幅度与地震的关系，并统计了2008—2018年出现的162次低点位移异常的地震预测对应率。结果显示，加入本文给出的相关方法异常判据后，地磁低点位移法报对率自39%增至56%，表明相比仅使用传统的低点位移法，基于日变化相关的地磁低点位移异常分析方法更有效。

Geomagnetic low-point displacement method was proposed in the 20th century. It has been applied to forecast earthquakes in short term, with the base of characteristics of geomagnetic low-point in main land China. However, since this method analyses geomagnetic distortions before and after noon only, the accuracy of forecasting in practice is relatively poor. In this paper, we conducted a statistical analysis on 162 geomagnetic low-point displacement anomalies between 2008 and 2018. All the anomalies are computed by using daily variation spatial correlation method. Our results show that the accuracy of earthquake forecasting increases by 44%, from 39% to 56% when using mean correlation coefficient to determine the validities of anomalies. This method is proved to be effective and practical.

P315

中国地震局震情跟踪定向工作任务(2021010408)、中国地震局地震科技星火计划项目(XH200501)共同资助