摘要
动态追踪了云南地区第4 强震活跃期6 .3 级以上强震前波速比异常图像,显示出明显的南北差异:滇西南的1988 年11 月6 日澜沧- 耿马7 .6 、7 . 2 级和1993 年1 月27 日普洱6 .3 级强震发生在低波速比异常区内; 中缅边境上的1992 年4 月23 日6 .7 、6 .8 级和1995 年7 月12 日孟连西7 .2 级强震发生在低波速比异常区边缘;而滇西北的1996 年2 月3 日丽江7 .0 级、1976 年11 月7 日、12 月14 日宁蒗6 .7 、6 .4 级和滇东的1995 年10 月24 日武定6 .5 级强震却都发生在高波速比异常区内.强震前近震震级 ML 与持续时间震级 MD 的震级差的南北差异也进一步证实了波速比异常的差别.
The pattern of v p/ v s ratio anomaly for M≥6.5 earthquakes in the fourth activity period in Yunnan area was dynamically traced,it clearly showed the difference in south and north. The Lancang Gengma M 7.6 and M 7.2 earthquakes on November 6,1988 and the Puer M 6.3 earthquake on January 27,1993 in southwest Yunnan occurred in low v p/ v s ratio anomaly area,the China Burma border M 6.7 and M 6.8 earthquakes on April 23,1992 and the west Menglian M 7.3 earthquake on July 12,1995 occurred along the margin of this area,while the Lijiang M 7.0 earthquake on February 3,1996,the Ninglang M 6.7 and M 6.4 earthquakes on November 7 and December 13,1976 and the Wuding M 6.5 earthquake on October 24,1995 occurred in high v p/ v s ratio anomaly region. Before strong earthquakes,the north south difference between near shock magnitude M L and continued time magnitude M D demonstrated further the difference of v p/ v s ratio.
出处
《西北地震学报》
CSCD
1999年第4期363-369,共7页
Northwestern Seismological Journal
基金
中国地震局"九五"攻关项目!(950404)
