中国的地震活动性

基于华北地震统计区近600年地震资料，采用最大熵谱分析方法，定量解析了该区及各主要地震带的地震活动时间序列特征，为多个优势周期叠加的复杂强弱交替。以最优分割法划分了华北地震区及各主要地震带的地震幕，分析了其特点。结合当前华北地震区地震平静现象等，认为目前该区地震活动趋势正处于一个复杂的十字路口，华北地区随时可能进入一个新的地震活动幕（将持续10年左右），然后进入新一轮地震平静期（将持续几十年）；也有另一种可能，华北地区现在实际已经进入了新的地震平静期。

The relationship between maximum entropy spectra and maximum likelihood spectra

According to the seismic data from the North China earthquake statistical area in recent 600 years, time series characteristics of seismic activities in this area and the main seismic zones are analyzed quantitatively by using the maximum entropy spectrum analysis method. The complex alternation of strength and weakness superimposed by multiple dominant periods is observed. The seismic episodes of the North China earthquake zone and the main seismic zones are divided by the Fisher method （optimal segmentation method ） and their characteristics are analyzed. Combined with the analysis of the current seismic quiescence in the North China earthquake region and other phenomena, it is believed that the current seismic trend in this region is at a complex crossroads. North China area may enter a new period of intense seismic activity at any time （it will last for about 10 years） followed by a new period of seismic quiescence （it will last for decades）; There is another possibility that North China has actually entered a new period of seismic quiescence already.