Internal structure of the Moon inferred from Apollo seismic data and selenodetic data from GRAIL and LLR

• Published in: Geophysical research letters 2015-09, Vol.42 (18), p.7351-7358
• Main Authors: Matsumoto, Koji, Yamada, Ryuhei, Kikuchi, Fuyuhiko, Kamata, Shunichi, Ishihara, Yoshiaki, Iwata, Takahiro, Hanada, Hideo, Sasaki, Sho
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Core-mantle boundary; Correlation; Data; Data recovery; Density; Evolution; GRAIL; Gravitation; Gravity; internal structure; Lasers; LLR; Love number; low-velocity zone; Lunar evolution; Lunar rangefinding; Mantle; Moon; Overturn; Recovery; Seismic data; Seismic velocities; Seismological data; Seismology; Titanium dioxide; Titanium oxides; Travel time; Velocity; Viscosity; Wave velocity
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2015GL065335

The internal structure of the Moon is important for discussions on its origin and evolution. However, the deep structure of the Moon is still debated due to the absence of comprehensive seismic data. This study explores lunar interior models by complementing Apollo seismic travel time data with selenodetic data which have recently been improved by Gravity Recovery and Interior Laboratory (GRAIL) and Lunar Laser Ranging (LLR). The observed data can be explained by models including a deep‐seated zone with a low velocity (S wave velocity = 2.9 ± 0.5 km/s) and a low viscosity (∼3 × 1016 Pa s). The thickness of this zone above the core‐mantle boundary is larger than 170 km, showing a negative correlation with the radius of the fluid outer core. The inferred density of the lowermost mantle suggests a high TiO2 content (>11 wt.%) which prefers a mantle overturn scenario. Key Points The lunar internal structure is investigated using Apollo travel time and improved selenodetic data At least a 170 km thick low‐velocity zone is required by the observation A lunar evolution model with a mantle overturn is supported