|Title||Interference of teleseismic body waves in noise cross-correlation functions in Southwest China|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||Wang W.T, Gerstoft P, Wang B.S|
|Journal||Seismological Research Letters|
|Type of Article||Article|
|Keywords||adjoint tomography; ambient seismic noise; arrays; direction; Geochemistry & Geophysics; greens-function; interferometry; locations; phase; secondary microseisms; source|
Vertical-vertical component noise cross-correlation functions (NCFs) from southwest China show strong signals at 4-8 s periods with apparent velocities exceeding 18 km/s. These signals exhibit clear azimuthal dependency and undergo seasonal variations. Using NCF-based beamforming, we isolate these signals from surface waves to better address their slowness distributions and source locations. They are identified as the interference of teleseismic P-wave microseisms. Backprojection results indicate that the sources are from deep oceans, consistent with previous studies. The inferred source locations are verified by the agreement between observed signals and their predicted arrival times. Our study suggests that knowledge of microseism sources helps identify various signals in NCFs and that analyzing these signals improves our understanding of the noise sources.