甘肃CZB型竖直摆倾斜仪观测数据震前异常分析

Analysis of variation characteristics of observation data of CZB type vertical pendulum tiltmeters in Gansu before earthquakes

甘肃省CZB型竖直摆倾斜仪观测资料显示,形变异常与中国大陆近年具有较大影响的一些地震存在对应关系,分析发现震前异常变化有2种:(1)渐进式异常变化;(2)台阶式异常变化。研究发现,在不同地震台站,同种倾斜仪器在同一地震前异常表现不同,分析认为异常形态与台址岩性和岩石完整程度有关,与台站所处地质构造和周围山体地貌有关。

The data recorded by CZB vertical pendulum tiltmeters installed in Gansu Province shows the relationship between anomalous phenomena of the crustal deformation and the earthquakes occuring in China continent in recent years. The crustal deformation data are recorded at stations located in Gansu. The relationship between the anomalous phenomena and the earthquake events is studied. Two types of abnormity variation features can be found：（1） Gradual model abnormity;（2） Stage style abnormity. The research shows that the same instruments installed in different stations recorded different phenomena before the same earthquake. The results indicated that the different anomalous phenomena can be owed to site lithology, rock mass completeness, geologic structure of stations and the mountain terrain surrounding stations.