Extracting 220 Hz information from 55 Hz field data by near-field superresolution imaging

Field experiments are used to unequivocally demonstrate seismic superresolution imaging of subwavelength objects in the near-field region of the source. The field test is for a conventional hammer source striking a metal plate near subwavelength scatterers and the seismic data are recorded by vertical-component geophones in the far-field locations of the sources. Time-reversal mirrors (TRMs) are then used to refocus the scattered energy with subwavelength resolution to the position of the original source. A spatial resolution of λ/10, where λ is the dominant wavelength associated with the data, is seen in the field tests that exceeds the Abbe resolution limit of λ/2.