Far-field superresolution by imaging of resonant multiples

We show that superresolution imaging in the far-field region of the sources and receivers is theoretically possible if migration of resonant multiples is employed. A resonant multiple is one that bounces back and forth between two scattering points or two neighboring reflectors. For a source with frequency f , N roundtrips in propagating between two scatterers increases the effective frequency to 2N × f and decreases the effective wavelength λ to λ/2N. Thus, interbed multiples can, in principle, be used as high-frequency probes to estimate detailed properties of layers. This is not only applicable to crustal reflections, but also to mantle and core reverberations of interest to earthquake seismologists.