华北地区中小地震重新定位和地震活动特征研究

选取了华北地区1978—2011年289个台站记录到的24753个地震事件, 使用双差定位方法对这些地震进行了重定位, 获得了20512个地震的重定位结果, 平均定位误差在EW、 NS、 UD方向分别为0.54 km, 0.57 km和0.57 km。 相比于初始结果和绝对定位结果, 双差定位结果在平面上分布更集中, 沿断裂分布特征更加明显, 震源深度也更加合理。 通过剖面分析, 张北地震带、 唐山地震带、 邢台地震带均为高倾角断裂, 南部剖面6震源深度分布有随时间变浅的趋势。 通过与前人的研究结果进行对比, 本次研究使用的时间较长, 地震数量较大, 得到了更加可信的结果。

Seismicity Characterized by Relocation of Small to Moderate Earthquakes in North China

There are 24753 seismic events recorded by 289 stations in North China in the period of 1978—2011. We relocated these events with the doubledifference location algorithm, and obtained the average position error of the relocation results of about 20512 earthquake, which were 0.54 km, 0.57 km and 0.57 km in the EW, NS, UD directions respectly. Compared with the initial results and absolute positioning results, our results are more concentrated in the plane distribution, the distribution is more obvious along fractures, and the focal depth is more reasonable. The profile analysis result shows that the Zhangbei seismic belt, Tangshan seismic belt, and Xingtai seismic zone are highangle faults, section profile 6 of focal depth distribution has the trend of shallow with time. Compared with the research of others, our research has a long time duration, earthquake number is larger, and the test results are more reliable.