摘要
对云南地区4个地震序列,分别为2000年姚安6.5级地震、2001年施甸5级震群、2001年永胜6.0级地震和2003年大姚6.2、6.1级震群,利用垂直向数字地震尾波分别计算地震序列周边台站3个频率段的Qc-1值,分析对比其时间演化趋势。发现对于主-余震型序列,主震后Qc-1值整体上变化幅度不大,趋于稳定。而对于震群(或双震)型序列,在第一个主震后,Qc-1值表现出上升-下降趋势,持续一段时间后强震发生。这些变化在序列周围的台站和三个频率段的变化整体趋势是一致的,但变化幅度不一致,可能与孕震区的位置和孕震应力的演变过程有关。上述研究为强余震的预报提供一个新的方法。
Three frequecy band＇s Q^-1c of four earthquake sequences in Yunnan Area, Yao＇an M6. 5 sequence in 2000, Shidian M5 sequences in 2001, Yongsheng M6 sequence in 2001 and Dayao M6.2, M6.1 sequence in 2003, are calculated with vertical digital seismogram in stations around the sequences. By analyzing and comparing their temporal charac teristies, we conclude that Q^-1c values to be stable after the main shock for mainshoek-aftershock sequences; but for mainshock swarm sequences, Q^-1c values would trend to be in- creasing at first after the first main shock then decreasing and after a short time lasting the next main earthquake occurs. Those tendencies show rough agreements for Q^-1c in stations around the sequences and three frequency bands except their amplitudes show varying, which would be related to the zone of earthquake generation and the progress of stress ac cumulation. This research provides a new way to predict strong aftershocks.
出处
《地震》
CSCD
北大核心
2006年第1期19-25,共7页
Earthquake
基金
"十五"国家科技攻关项目(2004BA601B01-04-03)
地震青年基金项目(140102-134-03)
