海底地震仪对海上地震定位精度的提升作用——以南澳外海域M_L2.8级地震为例

Development of Offshore Ocean Bottom Seismometer to Promote the Accuracy of Coastal Earthquakes Relocation——A M_L2.8 Earthquake in the Open Sea of Nanao

由于海底地震台站的缺乏,如何提高海域地震定位的精度是目前地震学家面临的问题之一。南海北部陆缘作为板内地震的活跃带,其微震活动在华南沿海和近海海域频发,海上由于未布设相应的地震台网,因此对近海海域地震尤其是微震的定位精度极低。利用2012年南海东北部海陆地震联测期间两台海底地震仪(Ocean Bottom Seismographs,OBS)所记录到的南澳外海域发生的ML2.8级地震为例,对比分析OBS数据加入前后对地震定位结果的影响。这是首次在南海北部陆缘利用OBS联合陆上地震台网对天然地震进行定位的对比研究,结果说明了近海海域OBS的布设将会对我国沿海地震定位精度的提升、地震活动性的特征以及海域断裂构造的研究具有极其重要的意义。

Due to the lack of seismologic observation stations, how to promote the accuracy of coastal earthquake location is one of important problems for seismologists now. As an active intraplate seismic zone, microearthquakes occurred at the northern margin of the South China Sea frequently, however, the accuracy of coastal earthquakes location, especially the microearthquakes location is extremely low for the lack of corresponding seismologic observation networks. The paper relocates a ME 2.8 earthquake which was captured by two Ocean Bottom Seismometers （OBS） in 2012 during the period of the onshore-offshore seisnfic experiment in northeastern South China Sea, and analyzes the influence of OBS data on seismic relocation. The studying on using the data of OBS and continental networks to relocate the natural earthquake is the first time in the northern margin of the South China Sea. The results inform that the offshore OBS is important to promote the accuracy of coastal earthquakes location, and understand seismic activity and undersea fault tectonic.