【摘要】 分析了华北地区1484年以来M≥5级地震平静现象:(1)华北地区1484—1730年及1815年以来2个地震活动期所有M≥5级地震平均平静时间为17.8个月,1731—1814年地震平静期的所有5级地震的平均平静时间约90.1个月,二者有明显差异;(2)华北地区2个地震活动期中相邻活动幕的幕间M≥5地震平均平静时间约86.4个月,与地震平静期大体一致,这样,90个月可以为华北地区M≥5级地震长期平静的标志性时间;(3)当前华北地区M≥5级地震平静时间达77个月,已接近长期平静的标志性时间,发生5级地震以上地震的可能已经很大;(4)上述工作成文后发生了2013年1月23日辽宁省辽阳市与沈阳市交界处5.1级地震,应注意华北进入新的地震活动幕。更多还原

【Abstract】 In this study,the M ≥5 seismic quiescence in North China since 1484 is discussed.The average time of M≥5 seismic quiescence is 17.8 months between two seismically activity periods.While the average time of the seismic quiescence period(1731—1814) is about 90.1 months.There is obvious difference between the two periods.Between the two seismically activity periods,the average time of M ≥5 seismic quiescence is about 86.4 months.It’s about the same length of time with the seismic quiescence period.So we can conclude that 90 months is the iconic time of the M ≥5 seismic quiescence in North China.Currently the time of M ≥5 seismic quiescence in North China is 77 months,and it has been close to the iconic time.There’s possibility that 5 or more magnitude earthquake will occur in North China.Actually,a 5.1 magnitude earthquake happened at the junction of Liaoning Shenyang and Liaoyang on January 23,2013 after completion of above work.It is worth attention that North China has entered a new earthquake activity period.更多还原