[S14-2] Upper mantle and transition zone dynamics and structure II

[S14-2-05] Towards 3D Kirchhoff Migration of Receiver Functions at Continental Scale

^○Florian Millet^{1, 2}, Thomas Bodin¹, Stephane Rondenay² (1.Universite Claude Bernard Lyon 1, Lyon, France, 2.Universitetet i Bergen, Bergen, Norway)

The coda of seismic body waves contains a wealth of information about heterogeneities and discontinuities inside the Earth. By using fast Receiver Function migration techniques such as classic Common Conversion point (CCP) stacking, one can easily interpret structural features down to a few hundred kilometers in the mantle. However, strong 1D assumptions limit the scope of these methods to stable regions such as cratons and stable basins. Other more accurate 2D and 2.5D methods are based on fewer assumptions, but rely on dense arrays of stations, and are computationally expensive. Following the ideas of Cheng et al. (2016), we have implemented a fully 3D prestack Kirchhof Receiver Function migration scheme where travel times are quickly computed with the use of a fast Eikonal solver. The method is tested using both 2.5D synthetics generated with a ray theory scheme (Raysum) and 3D synthetics using a spectral element method (specfem3D). Results show that dip angles and depths can be well recovered. Application of this method to field data should prove interesting, for example, in complex subduction zones that exhibit strong heterogeneities or multiple slabs.