云南近期几次M≥6.0级地震前水氡异常特征

Change characters of radon content in groundwater before several earthquakes with M ≥6.0 in Yunnan Province

对1998年11月19日宁蒗6 2级地震,2000年1月15日姚安6 5级地震和2001年10月27日永胜6 0级地震前后的云南水氡资料异常,用形态对比、二倍标准差等常用方法进行分析研究,结果表明,在M≥6 0级地震前,震中附近都有台站的水氡资料会出现长达1年以上的长期趋势异常;4个月的长、中期异常占异常台站的50%左右;震前3个月内出现的短临异常占异常台站的40%～50%,临震异常在震前几天到1个月之间出现,幅度大,时间短。3次M≥6 0级地震前,水氡异常总的特点是:长、中、短、临异常分别在单台表现突出;异常形态区别明显,异常不连续性特征普遍存在,继承性异常有所表现。

The change characters of observation data of radon content in groundwater in Yunnan Province before and after three earthquakes with M ≥6.0 are summarized.These earthquakes are Ninglang M 6.2 Earthquake on 19 November 1998,Yaoan M 6.5 Earthquake on 15 January 2000 and Yongshen M 6.0 Earthquake on 27 October 2001.We use an appearance compare and 2 times standard deviation as our index to find abnormal message relate to seismic events.We find:an earthquake with M≥6.0 can make it last for one year that a long-term tendency changes of the radon contents in groundwater;The medium term abnormal changes,which last for 4 months,exist in a half of stations around the epicenter of earthquake;The short-and impend abnormal changes exist several days to one month before the earthquake and their change amplitude of the abnormal data are big and clear.