%0 Journal Article %T 南北地震带北段6级以上地震前ML ≥ 3.0地震活动特征 %T Activity Characteristics of Weak Earthquakes before M ≥ 6.0 Earthquakes in the Northern Section of the North-South Seismic Belt %A 任雪梅 %A 曾宪伟 %A 丁风和 %A 蔡新华 %A Ren Xuemei %A Zeng Xianwei %A Ding Fenghe %A Cai Xinhua %J 中国地震 %@ 1001-4683 %V 34 %N 4 %D 2018 %P 818-827 %K 南北地震带北段;前兆性平静;增强;活跃;震中区 %K The north-south seismic zones;Precursory calm;Enhancement;Active;Epicentral area %X 对1970年以来南北地震带北段6级以上地震前的ML ≥ 3.0地震活动特征进行了分析,讨论了平静或增强现象的特征,并结合主震震源机制解和区域活动性差异,对6级以上地震的平静现象进行较为深入的分析。结果表明,主震前震中区ML ≥ 3.0地震活动主要存在平静异常,各个区域的平静特征和时间有差异,震中区ML ≥ 3.0地震平静持续时间的长短与其主震前活动水平密切相关。 %X In the northern section of the North-South Seismic Belt since 1970 activity characteristics of earthquakes with ML ≥ 3.0 before M ≥ 6.0 earthquakes are analyzed,and discussed the calm or enhanced characteristics of the phenomenon. On the basis of the main seismic source mechanism and the differences of regional activity,the calm phenomena of M ≥ 6.0 earthquakes are analyzed in depth. The results show that there is clam anomaly of seismic activity of earthquakes in the epicentral area before main shocks. The calm characteristics and time of each region are different. The duration of the calm of earthquakes with ML ≥ 3.0 in the epicentral area before main earthquake was closely related to the activity level before the main earthquake. %R %U http://zgdz.eq-j.cn/zgdz/home %1 JIS Version 3.0.0