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本文根据中国近海海域历史及现代强震活动的时空分布与相邻大陆地震活动的关系、强震发生的构造条件、震源机制应力场等探讨了该区地震活动特征.结果表明海域强震多分布在近海区:有渤海、南黄海二个强震集中、频度高的“地震窝”;有泉州、南澳和琼州三个强度高但频度低的强震区·海域强震活动与相邻大陆的大震活动时间有明显的相关性,整个海域的强震活动的时间分布亦有其共同的活跃期和平静期.海域强震发生的构造条件与大陆地震的相近,常发生在新生代特别是第四纪以来的强烈断陷区.海域地震应力场方向与邻近大陆的完全一致,它们好似大陆地震应力场轨迹线向板块边界处的自然延伸.该区强震活动与周围板块的构造运动密切相关.
In this paper, the characteristics of the seismic activity in this area are discussed according to the relationship between the spatial and temporal distribution of the history of China’s offshore seas and the activity of the adjacent areas, the tectonic conditions of the strong earthquakes, and the stress field of the focal mechanism. The results show that there are many distributions of strong earthquakes In the offshore area, there are two “strong earthquakes” concentrated in the Bohai Sea and the South Yellow Sea with strong and frequent earthquakes. Three high-intensity and low-frequency earthquakes in Quanzhou, Nan’ao and Qiongzhou, The time of strong earthquakes in the mainland is obviously correlated, and the time distribution of strong earthquakes in the whole sea area also has its common active period and quiet period. The tectonic conditions of strong earthquakes occur in the sea area are similar to those of the mainland earthquakes and often occur in the Cenozoic Especially the Quaternary Depression area.The seismic stress field in the sea area is completely consistent with the adjacent continent, which is similar to the natural extension of the earthquake stress field trajectory to the boundary of the plate.The seismic activity in this area is related to the structure of the surrounding plate Movement is closely related.