Tectonophysics ( IF 2.9 ) Pub Date : 2021-07-19 , DOI: 10.1016/j.tecto.2021.228998 Semir Över 1 , Süha Özden 2 , Alper Demirci 3 , Erdem Gündoğdu 4
On October 30, 2020, an earthquake with a magnitude of 6.8 (Mw) struck the northern coast of Samos Island in the Kuşadası Gulf. The solution to the focal mechanism indicates that the earthquake of 30 October 2020 occurred on a normal fault with nodal planes of E-W strike; thus, indicating extension in N-S direction. The fault plane solutions show a N-S trending extension for normal faults, which are obtained by inverting the moment tensor waveforms of 23 earthquakes and the P-wave first motion polarities of 11 aftershocks. A normal fault stress regime of approximately N-S (N6°E) σ3 axis is given by the inversion of slip vectors measured at sites located on land in Kuşadası. The mean R value is 0.84, suggesting that the stress regime is triaxial extensional stress state. The inversion of the focal mechanism of earthquakes occurring on land and in the Gulf of Kuşadası describes an extensional stress regime active today, characterized by an approximately N-S (N9°E) σ3 axis. The calculated R value of 0.31 indicates a triaxial stress state. For the 30 October 2020 earthquake (Mw:6.8), the Coulomb failure stress change analysis shows a substantial reduction in stress in the N-S direction supporting the kinematic results. The N-S extension in Western Anatolia-Aegean is largely influenced by the relatively fast movement of the Hellenic trench southwards, related to the sinking of the African plate beneath Aegean.
中文翻译:
2020年10月30日萨摩斯地震对爱琴海地球动力学背景的推论(Mw:6.8)
2020 年 10 月 30 日,库沙达斯湾萨摩斯岛北部海岸发生了 6.8 (Mw) 地震。震源机制解表明2020年10月30日的地震发生在一条正断层上,具有东西走向的节点平面;因此,表示在 NS 方向上的扩展。断层面解显示正断层的 NS 趋势扩展,这是通过反演 23 次地震的矩张量波形和 11 次余震的 P 波初动极性得到的。大约 NS (N6°E) σ3 轴的正断层应力状态是通过在位于 Kuşadası 陆地上的站点测量的滑动矢量反演给出的。平均 R 值为 0.84,表明应力状态为三轴拉伸应力状态。陆地和库沙达斯湾地震震源机制的反演描述了今天活跃的拉伸应力状态,其特征是近似 NS (N9°E) σ3 轴。计算出的 R 值为 0.31 表示三轴应力状态。对于 2020 年 10 月 30 日的地震(Mw:6.8),库仑破坏应力变化分析显示,NS 方向上的应力显着降低,支持运动学结果。西安纳托利亚-爱琴海的 NS 延伸在很大程度上受到希腊海沟向南相对快速移动的影响,与爱琴海下方的非洲板块下沉有关。对于 2020 年 10 月 30 日的地震(Mw:6.8),库仑破坏应力变化分析显示,NS 方向上的应力显着降低,支持运动学结果。西安纳托利亚-爱琴海的 NS 延伸在很大程度上受到希腊海沟向南相对快速移动的影响,与爱琴海下方的非洲板块下沉有关。对于 2020 年 10 月 30 日的地震(Mw:6.8),库仑破坏应力变化分析表明,NS 方向上的应力显着降低,支持运动学结果。西安纳托利亚-爱琴海的 NS 延伸在很大程度上受到希腊海沟向南相对快速移动的影响,与爱琴海下方的非洲板块下沉有关。