汶川地震前羊八井中子-μ子望远镜计数率异常

Abnormal count rate of Yangbajing neutron-muon telescope before Wenchuan earthquake

利用在西藏羊八井新建中子-μ子望远镜的观测数据,研究分析了在2008年5月12日四川汶川8.0地震期间宇宙线高能粒子偏离正常背景的异常变化。中子-μ子望远镜的中子监测器经过消除背景场和气压修正后震前5天特别是5月9日出现计数率降低异常。在地震发生前5天左右,μ子望远镜各方向计数率出现日变化异常。这些宇宙线异常现象,与其它观测资料,例如地磁低点位移、电离层总电子含量TEC、电离层测高仪得到的foF2和电磁卫星监测的离子密度和温度等,在时空分布上有较好的一致性。这是继羊八井中子监测器观测到震前宇宙线异常现象后,利用另一种宇宙线观测手段观测到的震前宇宙线异常现象。

Using the data obtained with a newly-built Yangbajing neutron-muon telescope in Tibet,the abnormal changes of high energy cosmic ray particles deviating from the normal background are studied.The neutron monitor count rates,after the elimination of the background field and the pressure correction,appear to be reduced abnormally 5 days before the earthquake,especially in May 9.About 5 days before earthquake,the muon telescope count rates have an abnormal diurnal variation in each direction.These cosmic ray abnormities,and other observations,such as the geomagnetic low-point displacement,total electron concentration（TEC）,foF2 obtained by ionosphere sounding and ion density and temperature detected by electromagnetic satellite,are consistency in space and time.Following the Yangbajing neutron monitor,the Yangbajing neutron-muon telescope also observed the anomalies in cosmic rays before the earthquake.