DETECTING EARTH’S FREE OSCILLATIONS BY USE OF GRAVITY OBSERVATIONS AT YICHANG STATION
Yuan Qu 1) ;Ren Jia 2) ;Fan Chunyan 3) ;Cheng Na 4) ; and Zhang Huan 5)
1)Yichang Seismostation of the Eaarthquake Administration of Hubei Province,Yichang 443002)Zhangjiakou Central Station of the Eaarthquake Administration of Hebei Province,Zhangjiakou 0750003)China Seismic Station Network Center,Beijing 1000454)Luoyang Seismostation of the Eaarthquake Administration of Henan Province,Luoyang 4710005)Sheshan Seismostation of the Eaarthquake Administration of Shanghai Minicipality,Shanghai 201602
Abstract:By use of the digitiled observations of the DZW microgal gravimeter at Yichang station without the corections of gravity tide and prossure the spherical free oscillations of the baseband 0S3-0S37 excited by the 26 Dec. 2004 Sumatra earthquake are exactly obtained with the method of power spectrum density estimation.After comparing it with the periods of the theoretical free oscillation calculated with the PREM model it is found out that the observed period coincides with the theoretical.Except for the 0S3,0S4,0S5,0S6 and 0S10 that their relative error between the observed period and the theoretical ones is more than 0.2%,for the most of the others the relative error is about 1%.
Yuan Qu ,Ren Jia ,Fan Chunyan et al. DETECTING EARTH’S FREE OSCILLATIONS BY USE OF GRAVITY OBSERVATIONS AT YICHANG STATION[J]. jgg, 2010, 30(Supp.1): 74-77.