基于POT模型的昆仑山地区地震统计特征分析

极值统计是研究较少发生但一旦发生即产生极大影响的随机事件的有效方法。本文以地震活动频繁的昆仑山地区作为研究区域，建立了基于广义帕累托分布的超阈值（POT）模型，并讨论了该地区若干地震活动性参数，包括强震震级分布、潜在震级上限、强震平均复发间隔、一定周期内的强震发震概率、一定时期内的重现水平和超定值重现震级。经统计分析得到:该地区震级阈值选定为M_S5.5，超阈值期望震级为M_S6.81，潜在震级上限高达M_S9.08，M_S8.0的平均复发间隔仅为66.8年，未来3年该地区发生M_S5.5～M_S6.5的概率在80%以上，百年重现水平即可达到历史最大震级M_S8.1。

Analysis of Seismic Statistical Characteristics Based on POT Model in Kunlun Mountain Area

Extreme value statistics is an effective method to study random events that rarely occur but can cause great impact once they occur. This article takes the Kunlun Mountains area with frequent seismic activities as the research area. We establish a peaks over threshold (POT) model based on the generalized Pareto distribution. Then we discuss several seismic activity parameters, including: strong earthquakes magnitude distribution, upper limit of potential magnitude, average recurrence period, probability of strong earthquakes in a certain period in the future, the recurrence level and expected recurrence magnitude in a certain period. According to statistical analysis, the magnitude threshold of the region is selected as M_S5.5. The expected magnitude over the threshold is M_S6.81 and the upper limit of potential magnitude is M_S9.08. The average recurrence period of M_S8.0 is only 66.8 years. The probabilities of M_S5.5 ~ M_S6.5 are all above 80%. The 100-year return period can reach the historical maximum magnitude M_S8.1.