Technique for Combining Surface Wave Tomography with Receiver Function Results for Studying Upper Mantle Velocity Structure

Abstract—A technique is proposed for joint inversion of the surface-wave velocity dispersion data from long travelpaths and the results of the receiver function method. The technique is based on a modification of a surface-wave tomography procedure and allows for the use of the data not only from travelpaths but also obtained at individual isolated points. Initially, the data are reduced to a single type: either to surface wave velocity by calculating the dispersion curve from the vertical velocity section obtained by the receiver function method or to shear wave velocity by one-dimensional inversion of surface-wave dispersion curves from travelpaths. Thus, from the computational point of view, the problem reduces to the following one: to obtain a smoothed estimate of a two-dimensional function from the values ​​of this function at individual points and its average values along lines (travelpaths) which can be considered as straight. A direct application of a surface-wave tomography procedure under the assumption that the points are lines of zero length is impossible because the solution turns out to be singular at the points. To get rid of this obstacle, it is proposed to replace the points by circles of a small radius surrounding these points. Then, the problem of tomography is generalized by using data not only from linear travelpaths, but also from circular travelpaths. A numerical study has shown that an addition of point data results in an increase in the resolution.