[S21-4] Lithospheric discontinuities II – Reflectivity

[S21-4-02] On the feasibility and use of teleseismic P-wave coda autocorrelation for mapping shallow seismic discontinuities

^○Thanh-Son Pham, Hrvoje Tkalcic (The Australian National University, Canberra, Australia)

Seismic body waves from distant earthquakes which propagate near-vertically beneath recording stations, provide tools for imaging shallow Earth structures with high vertical resolution. The most commonly used techniques such as P- and S-wave receiver functions utilize conversion mode from P- to S-waves or vice versa to retrieve information on the gradients of elastic properties in the crust and upper mantle. Here we demonstrate the feasibility and advantage of utilizing reflection signals through an improved method of teleseismic P-wave coda autocorrelation. We recover clear reflections independently on vertical and radial components, which provides complementary constraints on the subsurface structures. Field data from different geological settings: from ice-covered stations in Antarctica to bedrock stations on the Kaapvaal craton in South Africa were analyzed. The results from analyses show the feasibility of the method to unveil P- and S-wave reflection signals from shallow interfaces and the Moho discontinuity. The method holds the potential to be applied globally to enhance crustal structure in various geological settings.