汶川MS8.0地震前四川地区前兆异常及其统计分析

Precursory anomalies inSichuanregion before 2008 Wenchuan MS8.0 earthquake and their statistical analysis

  • 摘要: 研究了2008年5月12日汶川MS8.0地震前四川地区观测到的各种异常.异常项与所有测项(或测站、台、场地、井点、泉点)之比称为异常测项(测点)比,以下类同. 地震前四川地区流动短水准观测存在中长期趋势异常的场地比为0.28,异常测项比为0.20;流动短基线存在中期趋势异常的场地比为0.13,异常测项比为0.13;地倾斜类观测存在中期趋势异常的台站比0.17,异常测项比为0.13;地下水位观测存在中期趋势异常的水位井点比为0.20;温泉观测存在水温短期异常的泉点比为0.15;温泉水氡、气氡观测存在短期异常的台点比为0.08,异常测项比为0.04;井泉水质组分观测存在短期异常的台点比为0.20,异常测项比为0.04;视电阻率观测存在中期异常的台站比为0.17, 异常测项比为0.06.对同一观测台或场地有不同观测手段,分别计算了台或场地数:四川地区在汶川8.0级地震前各类观测台或场地共有172个,存在观测异常台或场地比为0.14,其中出现中期与短期异常场地比分别是0.08和0.03;各类观测项共有335项,异常测项比为0.09,其中出现中期与短期异常测项的占比分别是0.06和0.01.可见,震前仪器微观监测台或测项多数没有观测到突出异常现象.本文中其它没有提及的观测手段或观测项的资料,经过研究没有分析检测出异常项.

     

    Abstract: Various observation anomalies in Sichuan region before the 12 May 2008 Wenchuan MS8.0 earthquake were studied. The abnormal items against all of observation items (or observation stations, measuring platforms, sites, well points, spring points) are the ratio of abnormal items (points), following are similar. On the mobile short leveling, the site and item ratios of existing medium to long-erm trend anomalies are 0.28 and 0.20 respectively. On the mobile short baseline, the site and item ratios of existing medium-erm trend anomalies are 0.13 and 0.13 respectively. On the ground tilt measurement, the station ratio of medium-erm trend anomalies is 0.17, the abnormal item ratio is 0.13. On the groundwater level observation, the well point ratio of medium-erm trend anomalies is 0.20. On the hot spring observation, the spring point ratio of short-erm anomalies is 0.15. On the hot spring water-as radon observation, the station and point ratio of short-erm anomalies is 0.08, the abnormal item ratio is 0.04. On the well water quality component observation, the station and point ratio of short-erm anomalies is 0.02, the abnormal item ratio is 0.04. On the apparent resistivity, the station and items ratios of medium-erm anomalies are 0.17 and 0.06 respectively. There have various observation means in the same station or site, we calculate the station or site number. There are 172 various stations or sites in Sichuan area before the Wenchuan MS8.0 earthquake, and abnormal stations or sites ratio is 0.14, the site ratios of appearing medium-erm and short-erm anomalies are 0.08 and 0.03 respectively. The total of various observation items are 335, the ratio of abnormal items is 0.09. The ratios of medium-erm and short-erm abnormal items are 0.06 and 0.01 respectively. It is clear that there are not obvious anomalies recorded by station or observation items before the earthquake. As for other observation means and data of observation items which are not involved in this paper, after researching, there have no abnormal items.

     

/

返回文章
返回