【摘要】 四川省汶川县发生8级大地震以后,在陕西省宁强县设立余震监测点,实地定时观测了余震发生与壤中气中Rn、Hg含量变化的关系,观测时间17 a。结果发现:在发震断裂上盘的壤中气中,Hg含量一般大于200 ng/m3,是下盘的1倍以上(在有地裂缝的地段,Hg异常高达560 ng/m3),而Rn含量没有明显差异。沿发震主断裂走向,距震中越近,Rn、Hg的背景含量越高。在背景地段,壤中气Hg含量高于20 ng/m3,同时伴有Rn异常,预示300 km范围、4~48 h之内、高频率、4级以上余震发生的几率高;反之则预示无余震发生。更多还原

【Abstract】 After the 8.0 magnitude earthquake that occurred in Wenchuan County,Sichuan Province,the authors established monitoring points of aftershock in Ningqiang County,Shaanxi Province.The relationship between the aftershocks and the Rn-Hg content change in soil gas was observed on the spot and at regular intervals in 17 days.The results show that the soil gas mercury content is generally more than 200 ng /m3 in the hanging wall of the earthquake fault,the content value is two times higher than that of the footwall(In fractures along the section,mercury anomaly value can reach 560 ng/m3),but radon content value shows no distinct change.Along the strike of the seismogenic main fault,the closer it is to the epicenter,the higher the Rn,Hg background values are.If mercury content is more than 20 ng/m3 in the background section,there is Rn anomaly simultaneously,which Indicates that there might occur higher probability of aftershock with high-frequency and over 4.0 magnitude within 300 km and 4～48 hours;if things are not like that,the aftershock will not occur.更多还原