山东及邻区地震的重新定位及其与活动构造的关系

Relocation of earthquakes in Shandong and its neighboring areas in China and relationship between their tectonics

对山东及其邻区1975～2010年发生的地震经震相到时数据校正后,用双差定位(Hypodd)和Hypoinverse 2000定位法对其进行重新定位,分析结果表明:重新定位的地震在空间分布上与区域构造结合更为紧密,震源深度的分布与人工地震勘探所推测的断裂相吻合;研究区地震多发生在5～25km深度范围内,分别在10km和16km左右存在两个明显的优势分布层,推断为这两个优势分布层分别位于上地壳底面和中地壳;地震活动图像表明中强震易发生在上下地壳交界的脆-韧转换带内,是区域应力作用下深部构造动力与浅层断裂运动变形的结果。

The earthquake in and around Shandong Province from 1975 to 2010 were corrected precisely to onset time of seismic phase and relocated by using Double-Difference （Hypodd） method and Hypoinvers 2000 （Hypo 2000 ）. The results show that the relocated seismicity is clearly associated with regional tectonics in space, and is also in agreement with the existence of deep faults imaged by wide-angle and deep seismic reflection profiling. Most earthquakes are located in a scope of 5 ~ 25kin, and there are two visible predominant depths： about 10kin and 16kin. We infer that they are in the bottom of the upper crust and in the middle crust respectively. The image of seismic activity indicated that moderately strong earthquakes occurred in the brittle-ductile transition. That is the effect of the deep tectonic dynamics under the area stress and the deformation of the upper and shallow fault movement.