利用湖州台形变观测资料检测地震激发的地球球形自由振荡

Detecting the free oscillation of the earth by use of observational data at Huzhou Seismostation

摘要:

利用湖州地震台垂直摆倾斜仪、水管倾斜仪、伸缩仪和体应变仪等观测资料，采用功率谱密度估计方法，获得2011年3月11日日本9.0级大地震激发的0S5～0S50 基频球型自由振荡数据；比对PREM模型的理论计算周期，其相对偏差均小于1.2‰，且体应变观测的相对偏差最小；伸缩仪和体应变仪能清晰地检测到与地壳深部结构密切关系的0S2、0S3和0S4低阶振型。

Abstract:

By using digital observations of the pendulum tilt-meter，water tube tilt-meter，extensometer and volume-strain-meter at Huzhou seismic station and with power spectrum density estimation method，we acquired 0S5～0S50 fundamental sphere free oscillations caused by the March 11,2011 Japan earthquake，and then compared it with PREM model. The relative errors are mostly smaller than 1.2‰. Extensometer and volume-strain-meter can clearly detect 0S2,0S3 and0S4 which is closely related to the deep structure and earth's interior.