1890—2020年伊朗M_(S)≥6.8地震时空对称性及趋势分析

Space-time symmetry of M_(S)≥6.8 earthquakes in Iran from 1890 to 2020 and future earthquake situation

探寻区域地震的时空规律并进行趋势判断对防震减灾有重大的现实意义。选取1890—2020年伊朗M_(S)≥6.8地震数据,采用可公度方法、三性法和蝴蝶结构图等方法研究区域地震的时空对称性,并结合太阳黑子数、地球自转速度变化对发震的物理机理进行探讨。研究结果表明(1)伊朗的强震具有良好的可公度性,从时间趋势判断上看,2022年伊朗发生M_(S)≥6.8地震的信号最强,2024年次之,并且通过三性法得知发生在2022年底的可能性更大。(2)从空间对称性上看,根据历史地震的经纬度迁移和震中三角迁移规律,下一次地震发生在32°N,54°E东南方区域内的可能性较大。(3)伊朗M_(S)≥6.8地震多发生在太阳黑子的极值年和下降段;同时,强震多发生在地球自转减速期和日长极值年及其附近,这在一定程度上佐证了灾害时空对称方法的可靠性。本研究进一步深化了对地震的规律认识,同时对三性法在区域上的应用有一定探索意义。

It is of great practical significance for earthquake prevention and disaster reduction to explore the spatiotemporal regularity of regional earthquakes and evaluate the future earthquake situation.In this study,we selected M_(S)≥6.8 earthquakes in Iran from 1890 to 2020.The space-time symmetry of regional earthquakes was analyzed using the commensurability method,triplet method,and butterfly structure diagram,and the physical mechanism of earthquakes was discussed in combination with the changes in the sunspot number and Earth’s rotation speed.The results show the following:(1)The strong earthquakes in Iran have good commensurability.According to the temporal symmetry trend,the signal of the next M_(S)≥6.8 earthquake in Iran is strongest in 2022,followed by that in 2024.Moreover,it is more likely to happen at the end of 2022 via the triplet method.(2)In terms of spatial symmetry,the next earthquake is more likely to occur in the southeast region of 32°N,54°E according to the migration rule of the longitude and latitude and the epicentral triangle rule of historical earthquakes.(3)The M_(S)≥6.8 earthquakes in Iran mostly occurred in the extreme years and the descending period of sunspots.At the same time,they mostly happened during the deceleration period of the Earth’s rotation and the extreme years of the day length,which proves the reliability of the space-time symmetry method to a certain extent.This study further deepens the understanding of the regularity of earthquakes and has a certain explorative significance for the regional application of the triplet method.