Abstract—

The geophysical effects of a strong seismic event as two earthquakes with magnitudes of 6.8 and 4.9 occurred on September 8, 2023, in Morocco at close times 22:11 and 22:30 UTC with an epicentral distance between the foci of ~4 km were considered. The data of a number of INTERMAGNET observatories and the magnetic recording results obtained at the Mikhnevo Geophysical Observatory of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences, were used. In the absence of considerable global disturbances of the Earth’s magnetic field, earthquakes were accompanied by a series of three positive bay-shaped geomagnetic variations with a maximum amplitude from ~1 to ~10 nT, following each other after ~60 min. The maxima of the induced magnetic field variations were observed almost synchronously at a distance from ~800 to ~10000 km. The magnetic effect delay time relative to the main shock of the first earthquake was ~70 min. Taking into account the almost planetary nature and high synchronicity of the magnetic field disturbances caused over a significant range of distances, as well as the time delays corresponding in order of magnitude to the travel time of the seismic signal of a distance multiple of the Earth’s dimension, it is suggested that the magnetic effect of the seismic event in question was caused by a global source such as an excited geodynamo. The ionospheric effect of the seismic event under consideration is reported as variations in the critical frequency f₀F2 calculated from the data obtained by the ground-based sounding station of the del Ebre Observatory.

中文翻译：

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2023年9月8日摩洛哥连续两次强震的地磁和电离层影响

摘要-

考虑了 2023 年 9 月 8 日世界标准时间 22:11 和 22:30 在摩洛哥发生的两次震级为 6.8 和 4.9 级的强烈地震事件的地球物理影响，震源之间的距离约为 4 km 。使用了多个INTERMAGNET观测站的数据以及俄罗斯科学院萨多夫斯基地圈动力学研究所Mikhnevo地球物理观测站获得的磁记录结果。在地球磁场没有出现相当大的全球扰动的情况下，地震伴随着一系列三个正湾形地磁变化，最大幅度从~1到~10 nT，在~60分钟后相互跟随。在约 800 至约 10000 公里的距离处几乎同时观察到感应磁场变化的最大值。磁效应相对于第一次地震主震的延迟时间约为70分钟。考虑到在相当大的距离范围内引起的磁场扰动的几乎行星性质和高度同步性，以及与地球尺寸倍数距离的地震信号的传播时间相对应的时间延迟，这表明所讨论的地震事件的磁效应是由全球源（例如受激的地球发电机）引起的。所考虑的地震事件的电离层效应被报告为临界频率f ₀ F 2 的变化，该频率是根据德尔埃布雷天文台地面探测站获得的数据计算得出的。