新地震区划图潜在震源区划分的主要技术特色

简要介绍了新地震区划图潜在震源区划分方案的形成过程,重点分析了潜在震源区三级划分、东西部地区潜在震源区划分技术途径的差异、不同级别活动块体边界带对高震级潜在震源区划分的控制作用、发震构造模型及其在潜在震源区划分中的应用等主要技术特色.共划分出29个地震带、77个地震构造区和1199个潜在震源区.与中国地震动参数区划图(2001)中综合方案相比,东西部地区潜在震源区的个数都有较大的增加,其中东部地区体现在震级上限6.0、6.5和7.0级的中强潜在震源区个数的明显增加,与划分工作中加强了该地区中强地震发震构造的判识研究相关;而西部地区体现在震级上限7.5和8.0级的高震级潜在震源区个数的大幅度增加,与划分工作中注重了活动块体边界带高震级潜在震源区划分,以及强调应用发震构造模型指导潜在震源区划分的技术特色相协调.

The Technical Highlights in Identifying the Potential Seismic Sources for the Update of National Seismic Zoning Map of China

After a brief introduction to the working process in identifying the potential seismic sources for the update of National Seismic Zoning Map of China, this paper summarizes four technical highlights, i.e. adopting the principle of three-level delineation, developing different technical approaches for higher seismic activity areas (e.g. the western China) and lower seismic activity areas (e.g. eastern China) separately, enhancing the upper limit magnitude of the potential seismic sources along the boarding zone of larger active blocks, and emphasizing establishment of the seismogenic models in each seismotectonic province and its application on delineating potential seismic source. The principle of three-level delineation was adopted in order to illustrate special irregularity of earthquake distribution. The first level of delineation is seismic belt which size is large enough to containing adequate earthquake data for statistical analysis. The second level is seismotectonic province that is delineated in each seismic belt for distinguishing different seismic activity background. The third level is potential seismic source that is identified according to clearer structural and seismic features in corresponding seismotectonic province. There are 29 seismic belts, 77 seismotectonic provinces, and 1199 potential seismic sources identified in China and adjacent region. Compared to the previous national seismic zoning map, the number of the potential seismic sources with higher-rank upper limit magnitude in western region is increased greatly. The number of the potential seismic sources of middle-rank magnitude in eastern region is increased too.