Inversion of teleseismic waves at Shidao Seismographic Station

	Inversion of teleseismic waves at Shidao Seismographic Station
	Ruan Aiguo ; Li Jiabiao ; Hao Tianyao ; Wu Qingju ; Xu Yi
刊名	ACTA OCEANOLOGICA SINICA
	2006
卷号	25 期号:5 页码:63-73
关键词	South China Sea s Wave Splitting Receiver Function s Wave Velocity Structure Waveform Inversion
ISSN号	0253-505X
文献子类	Article
英文摘要	Teleseismic datasets at the Shidao Seismographic Station, located in the northwestern South China Sea, are used to determine the earth anisotropy and the vertical distribution pattern of the shear wave velocity by inversion approaches. The rotated correction function is applied to analyzing high quality ScS records from five earthquakes at distance of 25 degrees similar to 35 degrees to obtain shear wave splitting parameters of the lithosphere. The result from the deepest earthquake among the five events indicates that the polarization of the fast shear wave is N94 degrees E, which means the direction of extensional stress or the moving of the upper mantle mass in Xisha Islands is nearly west to east and confirms that the crust in this region is a transitional one and the driving force beneath the crust is from the moving mass consistent with the Eurasian plate. The anisotropy effective thickness is estimated about 100 km based on the time delay of 1.3 s between the fast and slow shear waves. The receiver function is applied to analyzing high quality P wave records from nine earthquakes at distance of 20 degrees similar to 60 degrees to obtain the vertical distribution pattern of shear wave velocity beneath the station. The result indicates that the crust could be divided into three layers: the uppermost crust (5 km above) is a velocity gradient zone consisting of several small layers, where the shear wave velocity increases from 1.5 to 3.5 km/s gradually; the 5 similar to 16 km depth interval also consists of several small layers of which the mean velocity is about 3.8 km/s; and the lower crust (16.0 similar to 26.5 km) is an obvious low velocity layer with a velocity of about 3.6 km/s. The buried depth of the Moho discontinuity is 26.5 km, the mean velocity of the layers beneath the Moho is about 4.7 km/s and there is an obvious low velocity layer just beneath the Moho. Moreover, analysis of the arrival time of converted waves and the swinging variation of velocity around the initial model suggests that smaller layers in the model maybe are not reliable but the low velocity layer between 16 and 26.5 km maybe is the real one that implies the plasticity of the lower crust.
WOS关键词	STRATIFIED HALF-SPACE ; SOUTH CHINA SEA/ ; CRUSTAL STRUCTURE ; SEISMIC-WAVES ; MANTLE ; ANISOTROPY
WOS研究方向	Oceanography
语种	英语
出版者	CHINA OCEAN PRESS
WOS记录号	WOS:000241606800006
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/66138]
专题	中国科学院地质与地球物理研究所
通讯作者	Ruan Aiguo
作者单位	1.State Ocean Adm, Key Lab Submarine Geosci, Hangzhou 310012, Peoples R China 2.State Ocean Adm, Inst Oceanog 2, Hangzhou 310012, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100101, Peoples R China 4.China Seismol Bur, Inst Geophys, Beijing 100081, Peoples R China
推荐引用方式 GB/T 7714	Ruan Aiguo,Li Jiabiao,Hao Tianyao,et al. Inversion of teleseismic waves at Shidao Seismographic Station[J]. ACTA OCEANOLOGICA SINICA,2006,25(5):63-73.
APA	Ruan Aiguo,Li Jiabiao,Hao Tianyao,Wu Qingju,&Xu Yi.(2006).Inversion of teleseismic waves at Shidao Seismographic Station.ACTA OCEANOLOGICA SINICA,25(5),63-73.
MLA	Ruan Aiguo,et al."Inversion of teleseismic waves at Shidao Seismographic Station".ACTA OCEANOLOGICA SINICA 25.5(2006):63-73.