Surface wave tomography on a large-scale seismic array combining ambient noise and teleseismic earthquake data

摘要

We discuss two array-based tomography methods,ambient noise tomography (ANT) and two-planewave earthquake tomography (TPWT),which are capable of taking advantage of emerging large-scale broadband seismic arrays to generate high resolution phase velocity maps,but in complementary period band:ANT at 8-40 s and TPWT at 25-100 s period.Combining these two methods generates surface wave dispersion maps from 8 to 100 s periods,which can be used to construct a 3D v S model from the surface to ～200 km depth.As an illustration,we apply the two methods to the USArray/Transportable Array.We process seismic noise data from over 1 500 stations obtained from 2005 through 2009 to produce Rayleigh wave phase velocity maps from 8 to 40 s period,and also perform TPWT using ～450 teleseismic earthquakes to obtain phase velocity maps between 25 and 100 s period.Combining dispersion maps from ANT and TPWT,we construct a 3D vS model from the surface to a depth of 160 km in the western and central USA.These surface wave tomography methods can also be applied to other rapidly growing seismic networks such as those in China.