地震活动性参数估计的K方法及潜在震源区边界不确定性的影响

The K Method for Estimation of Earthquake Activity Parameters and the Effect of the Source Zone Boundary Uncertainty ──Discussion about Seismic Zoning Methods

本文在两个方面介绍了可用于地震区划的新方法。一方面是在ｂ值及年发生率估计中，现有地震目录由两部分组成，一为历史地震目录，二为现今中小地震目录，仅用其一部分都具有缺陷。本文介绍的Ｋ方法用最大似然法估计ｂ值及年发生率就是考虑了地震资料的不完整性，将历史资料与现今地震资料结合使用，并考虑了震级的不确定性，以期得到更符合实际的地震活动性参数。另一方面是在地震危险性分析中，考虑了潜在震源区的边界不确定性，使地震发生率在潜在震源区的边界附近是连续变化的，避免了突变和计算结果有过大的变化梯度。

Two new methods are introduced in this paper, which could be used for seismic zoning. One approach to the problem of b and annual activity rate evaluation was proposed by Kijko and Sellevoll. Exsiting earthquake catalog contains both historical and recent instrumental data sets. It is not adequate to use only one part of them. Combining the large historical events and recent complete observations and taking the magnitude uncertainty into account, the Kijko's method gives out the maximum likelihood estimation of b value and annual activity rate, which might be more realistic. The other method introduced that considers the source zone boundary uncertainty in seismic hazard analysis, which means .the earthquake activity rate across a boundary of source zone changes smoothly instead ofabruptly and avoids too large gradient in calculated results.