Evaluating Seismic Ambient Noise Techniques for Detecting Ice-Bearing Rocks on the Moon

Abstract

One of the primary objectives of upcoming lunar missions is to locate ice-bearing rocks at the South Pole. While evidence for their presence exists, the exact distribution and quantity remain uncertain. In this study, we evaluate the potential of seismic ambient noise techniques—including seismic interferometry, H/V spectral ratios, distributed acoustic sensing (DAS), and rotational measurements—for detecting ice-bearing rocks on the Moon. To achieve this, we perform 2D numerical simulations using a digital twin model of the shallow subsurface, incorporating high-velocity heterogeneities. Hereby, the resolution limits of the different methods are evaluated. Phase velocity dispersion curves of Rayleigh waves are extracted from DAS and rotational data, while group velocity dispersion curves are derived from interferometry. The strong scattering effects of the lunar regolith, in particular, influence the seismic interferometry results for large inter-station distances. While all methods reveal clear signatures of ice-bearing rocks due to the strong velocity increase, even for small weight percentages of ice, a combination of techniques is needed to achieve accurate resolution of depth, width, and ice content.