Comparative Study of Seismic Scattering Structures and Temporal Variations in Earth, Mars, and the Moon

Objective

The deep interiors of planets hold clues to fundamental questions in planetary science: How do planets evolve? Why do some remain geologically active while others fall silent? Earth, Mars, and the Moon, the three neighboring bodies, offer a natural laboratory for addressing these questions. Earth’s convecting core sustains a magnetic field, while Mars has lost its shield and the Moon has been inactive for billions of years. Yet, unlike Earth, Mars and the Moon preserve ancient records of planetary history due to the absence of plate tectonics. Comparing their interiors thus offers a unique view into the diversity of planetary evolution and the conditions controlling geological longevity. Seismology is the most powerful tool for probing planetary interiors, but for Mars and the Moon our knowledge remains fragmentary. Despite seismic data from InSight and Apollo, key parameters such as crustal thickness and core size remain uncertain. This is largely due to strong seismic scattering in their heterogeneous interiors. Scattered waves obscure primary phases much like echoes blur a voice, producing prolonged codas rather than sharp arrivals as on Earth. SeisEchoPlanets (from “seismic echoes” and “planets”) captures the central idea: just as sound reverberates in a hall, seismic waves can reverberate within a planet’s interior when scattered repeatedly, carrying rich information about its structure and evolution. This project treats such echoes not as noise, but as signals that encode the scattering properties and their temporal changes. I will conduct a comparative analysis of seismic codas from Earth, Mars, and the Moon, extracting parameters such as rise time, decay time, and attenuation using modeling and envelope-fitting tools already in my toolkit. The results will form the basis for interpreting data from upcoming missions, including FSS/Chang’E-7, Dragonfly, and Europa Seismic Package, advancing a new era of planetary seismology in echo-dominated environments.