Study on the Origin of the Body Wave Extracted from Ambient Seismic Noise Cross-Correlation Function in Yunan
详细信息
- 责任者：Wang Weitao (Institute of Geophysics ; China Earthquake Administration ; Beijing 100081 ; China) ; Yang Runhai
- 刊名：Journal of Seismological Research
- 出版年：2011
- 卷期：34(3)
- 关键词：远震信号 ; teleseismic signals ; 云南 ; Yunnan Province
- 页码：p.350-357
- 图表：7 illus., 32 refs.
- 分类号：0500
- 出版序号：112
- issnNo：ISSN1000-0666
- isbnNo：CN53-1062/P
摘要
Using vertical component records observed at 43 broad-band seismic stations from 2008 to 2010 in Yunnan,we calculate the noise-cross correlation functions between each station-pair and obtain Raleigh surface wave in the period from 5s to 40s.We find that in the period from 5s to 10s,and before Rayleigh wave,there is a strong precursory wave whose dominant frequency band is between 0.1 Hz and 0.2 Hz and whose arrival time is near the zero of cross correlation functions.Moreover its negative arrival-time in Winter alternates with the positive ones in Summer.Through further analysis of particle-motion,we confirm that this wave is P-wave with smaller reflection angle whose apparent velocity is about 30km/s.Referring to the relevant research results,we conclude that originating from the ambient micro-tremor noise source at a teleseismic distance,P-wave travels through deep earth to Yunnan and reaches a higher apparent velocity.The ambient noise source,which locates in South Indian Ocean in Summer and North Pacific Ocean in Winter,varies seasonally and spatially.