利用帕金森矢量检测2019年长宁6.0级地震的地磁场变化

2019年6月17日在四川长宁县(104.9°E、 28.34°N)发生6.0级地震。 本文以该地震为例, 基于中国地磁台网提供的地磁台站资料, 利用帕金森矢量方法, 计算出每个台站在不同频段的帕金森矢量方位角异常之后, 将同一频段的多个台站的异常进行叠加, 提取和分析该地震前震中周围地磁场变化特征。 结果显示, 震中周围多个台站短临地磁异常时空特征明显, 通过异常综合叠加分析可以较好地估计震中方位。 该研究结果可为今后短临地震预报提供一定参考价值。

Using Parkinson Vector Analysis to Detect the Geomagnetic Changes in the Sichuan Changning 6.0 Earthquakesof June 17, 2019

Seismo-magnetic anomalies induced from the existence of current and/or high-conductivity materials have been widely reported. The Parkinson vectors derived from geomagnetic data at 3 stations were obtained via the magnetic transfer function and discussed with respect to the location (104.9°E, 28.34°N) and the depth (19 km) of the Changning earthquake on June 17, 2019 in Sichuan province. Azimuth distribution constructed from the entire Parkinson vectors during the observation period is utilized to estimate the persistent background (i.e., underlying inhomogeneous tectonic structures) at each station. The normalized background distribution is subtracted from the normalized monitoring distributions computed using the azimuths of the Parkinson vectors within a 15-day moving window to determine the anomalous azimuths of high-conductivity materials. The analytical results show that high-conductivity materials appeared before 1~2 week and in areas about 15 km away from the epicenter reported by the China earthquake networks center.