Gravitational waves could map the Moon's interior like seismic tomography

When a gravitational wave passes through the Moon, it rings the body like a bell — and if the wave's amplitude is already measured by Earth-based detectors, the Moon's seismic response becomes a precision probe of its interior. This paper builds a perturbative framework connecting small changes in the Moon's elastic moduli, density, and layer boundaries to shifts in the frequencies and amplitudes of excited normal modes. Applying the formalism shows that calibrated gravitational-wave sources could reduce errors in lunar elastic parameters by about an order of magnitude compared to conventional seismology alone, providing fresh motivation for placing seismometers on the Moon.