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海丰震区发育着规模宏大的 NE 向海丰—梅陇断裂及一系列与其平行的次级断裂.同时,还存在与其共轭的断续分布的 NW 向断裂.震群中的三个子群的主震的震源机制解非常类似,其中一节面为 NE,另一节面为 NW.从余震的空间分布及极震区的长轴方向来看,2月26日 M_L3.3和4月9日 M_L,4.2地震的断层面为 NE 向;而3月14日 M_L,3.4地震,其断层面应取 NW 向.又据137个小震的四个台的 P 波初动符号的组合特征,可划分为八个类型并作出相应的迭加震源机制解.综上所述,本区破裂过程,主震及Ⅰ、Ⅳ 类地震是岩块沿NE 及 NW 向共轭构造的粘滑;Ⅱ—Ⅴ、Ⅶ、Ⅷ 类地震是岩块在粘滑过程中对前后邻接岩块引起平行滑动方向的挤压(前)和引张(后)的转换应力场所产生的剪切破裂.
In the Haifeng earthquake zone, a large-scale NE-Haifeng-Meilong fault and a series of parallel sub-faults are developed, and there are also conjugate discontinuous NW trending fractures.These three subgroups Of the main shock focal mechanism solution is very similar, one section of the NE, the other section of the NW from the spatial distribution of aftershocks and the long axis of the polar region direction, February 26 M_L3.3 and April On the 9th, the fault plane of M_L, 4.2 earthquake is NE direction, and the M_L, 3.4 earthquake on March 14 should have NW fault plane.According to the combined characteristics of the P-wave prime mover symbols of the four stations of 137 small earthquakes , Which can be divided into eight types and corresponding focal mechanism solutions are added.In conclusion, the rupture processes, main shocks and type I and type IV earthquakes in this area are stick-slip along the NE and NW conjugate structures. Ⅱ-Ⅴ, Ⅶ and Ⅷ earthquakes are shear fractures caused by the squeezing (anterior) and extension (posterior) transformational stresses in parallel sliding directions of the adjacent rock masses during the stick-slip process.