Wavefield Imaging of the Mantle of North America with 3D, Plane-wave Migration

Indiana University, Bloomington IN

Investigators

Abstract

This project is applying a recently developed, three-dimensional, direct wavefield imaging method to Earthscope Transportable Array (TA) data. The approach applies a series of algorithms that implement a form of three-dimensional, migration inversion. Three-component waveforms of body waves recorded by the TA are manipulated in a manner similar to seismic reflection processing to produce a three-dimensional image volume of P to S scattering strength beneath the continent. The method is being used to produce high-resolution images of the subducting lithosphere of the Juan de Fuca/Farallon system and to develop a 3D model of the geometry of that system. As the array moves eastward the method will be used to image lithospheric scale boundaries that can be applied to test models of how the Precambrian core of the continent was assembled. Technical problems being attacked to improve the capabilities of this new method are: (1) extension of the method to image S to P conversions, (2) new methods for estimating the impulse response of the medium (deconvolution), (3) improved handling of irregular data that are the norm for passive arrays, (4) improved error appraisal metrics, and (5) multiple removal. Broader impacts include support for a PhD student's research and plans to make 3D image volumes available via the web.