前兆异常区地震危险性概率的评估方法

讨论了根据前兆观测估计地震危险性概率的问题，给出了单学科观测异常区和多学科观测异常区地震的危险性概率的评估方法。利用３ 个先验概率值，即地震背景概率—Ｐ（Ｂ）、孕震条件下某学科观测发生异常的概率—Ｐ（Ａｉ／Ｂ）、非孕震条件下某学科观测发生异常的概率—Ｐ（Ａｉ／Ｂ），就可计算：①异常区有震概率（也称有震报准概率）Ｐ（Ｂ／Ａ） 或Ｐ（Ｂ／ ∩ｎｉ＝ １Ａｉ） 和异常区无震概率（也称虚报概率）Ｐ（Ｂ／Ａ） 或Ｐ（Ｂ／ ∩ｎｉ＝ １Ａｉ）；②非异常区有震概率（也称漏报概率）Ｐ（Ｂ／Ａ）或Ｐ（Ｂ／ ∩ｎｉ＝ １Ａｉ）和无异常无震概率（也称无震报准概率）Ｐ（Ｂ／Ａ） 或Ｐ（Ｂ／ ∩ｎｉ＝ １Ａｉ）。通过几组模拟数据的计算，可初步得出结论：①对于单学科观测，降低非孕震异常概率，即减小干扰，可提高报准概率；②多学科观测同时出现异常，将提高报准概率，但漏报概率也将显著增加。

A METHOD FOR ASSESSING EARTHQUAKE RISK PROBABILITY IN A PRECURSORY ANOMALOUS AREA

The earthquake risk probability in a precursory anomalous area is assessed based on the principle of conditional probability. A set of probabilities including probabilities of earthquake and none earthquake in an anomalous and a non anomalous area can be calculated if three prior probabilities which are background probability of seismic activities and precursory anomalous probabilities under conditions of earthquake and non earthquake development ,are given. After calculations with the simulative data, it can be concluded that 1)decreasing precursory anomalous probability under non earthquake development condition can increase the probability of successfully forecasting earthquake and 2) when multi disciplinary anomalies occurring, the probability of successfully forecasting earthquake will rise, but the probability of missing earthquake will also quickly increase.