中国强震的震级下限确定及有关震源参数的讨论

本文提出了能量达到一定阈值时震源断层面宽度在孕震层内达到饱和的观点。由此观点结合实际地震资料得到中国大陆大震的下限震级为7.1,相应的孕震层厚度为20km。在具有同样介质强度条件下,推得不同断层面宽度情况下震源体线性尺度与震级的关系式。研究表明我国浅源地震震源断层面宽度和长度是互补的,因此震源断层面积A、镨动幅度D和地震矩m_0与震级的关系在整个震级范围内(M=5—8.5)具有统一的表达式。

DETERMINATION OF LOWER-LIMIT MAGNITUDE OF STRONG EARTHQUAKE IN CHINA AND DISCUSSION ON SOURCE PARAMETERS CONCERNED

This paper proposes the view that the width of source fault plane got saturated in seismogenic layer when the energy reaches certain threshold value. Based on the view, combining actual seismic data,the author draws the conclusion that the lower-limit magnitude of strong earthquake is 7.1 in Chinese Continent,and the thickness of seismogenic layer is 20km. In the condition of the same medium strength, the relative expression between source linear dimension and magnitude is derived in the case of different fault plane width. The research suggests that the width and length of source fault plane of shallow focus shock in China is complementary. As a result, it is a unified expression among the area Of-source fault,dislocation, seismic moment with magnitude (M=5-8.5).