汶川8.0级地震前BSQ型数字垂直摆倾斜仪观测到的地形变异常现象

Abnormal Changes of Crustal Deformation before Wenchuan 8.0 Earthquake Observed by BSQ Model Digital Tilt Meter

地倾斜连续观测是地壳形变观测研究中重要内容。汶川8.0级地震前,布设在四川德阳金河测点的新型BSQ型数字垂直摆倾斜仪观测到了明显的地形变异常现象。分析其观测结果可知,汶川8.0级地震前约半月时间内德阳金河测点的地倾斜运动速度较过去的平均运动水平提高了数十倍,且震前地表快速倾斜的方向在N25°W左右。除此之外,德阳金河BSQ型数字垂直摆倾斜仪测点还观测到较为完整的,对应于可以反映地表应力集中、释放过程的震前地表破裂过程。上述现象为今后研究强震孕育机理提供了重要的信息。介绍与分析了布设在龙门山断裂带附近的其它类型地倾斜仪在震前的观测结果。事实证明,BSQ型数字垂直摆倾斜仪在强震前的浅表过程监测中具有重要意义,值得在今后的地震前兆台网工作中进行推广。

Continuous ground tilt observation is important in crustal deformation studies.The new BSQ model digital vertical pendulum tilt meter installed at Jinhe observation station in Deyang city,Sichuan Province caught abnormal ground deformation obviously before the Wenchuan 8.0 earthquake.According to the observation results,beginning from half a month before the earthquake,the ground tilt rates at the Jinhe station became tens of times stronger compared to that of before,and the tilt direction was about NW 25°.Besides,the BSQ model tilt meter here also got relatively complete information about stress accumulation and release before and during the earthquake process.It provided important information for studying strong earthquake process. The article also introduced the observation results from other kinds of tilt meters before the Wenchuan earthquake installed near the Longmenshan fault.This research proved that the BSQ model digital tilt meter can get more useful information about the deformation of ground surface,and worthy to be popularized.