17:15 〜 19:15
[PPS08-P17] Numerical experiments of lunar seismic wave propagation: Case study at Szilard crater
キーワード：月、月震、惑星地震学
One of the unique features of lunar seismic signals is their spindle shape, which reflects the intense scattering caused by structural heterogeneity inside the Moon (e.g., Blanchette-Guertin et al., 2012; Gillet et al., 2017; Onodera et al., 2022). As described in Earth seismology, the determination of the internal structure is highly dependent on the precision of seismic phase identifications (e.g., P, S), and the intensely scattered moonquake signals prevent us from constructing a precise internal structure model. Thus, understanding the scattering mechanism is a crucial step toward the improved assessment of the lunar interior.
In these years, lunar seismic scattering was investigated through data analyses and numerical simulations (e.g., Gillet et al., 2017; Onodera et al., 2022), and the contribution of heterogeneous media in the lunar crust, such as megaregolith, has been understood better. On the other hand, the influence of topography (e.g., surface craters, mantle plugs) has less been discussed. While the Apollo landing sites (especially Apollo 12 & 14) are relatively flat, the far side or polar regions host large topographic features, such as basins, which can strongly affect the seismic wave propagation and, therefore, the estimation of interior structure.
In this study, I numerically simulated impact-induced seismic waves occurring on Szilard crater located on the far side of the Moon, where many craters and a subsurface mantle plug coexist. In the presentation, I will show preliminary results of how lunar topographic features, in addition to megaregolith, affect seismic wave propagation and discuss what kind of seismic observations are preferred to illuminate the detailed crustal structure.
References:
Blanchette-Guertin et al. (2012), JGR, 117 (E6), E06003.
Gillet et al. (2017), PEPI, 262, 28-40.
Onodera et al. (2022), JGR: Planets, 127 (12), e2022JE007558.
In these years, lunar seismic scattering was investigated through data analyses and numerical simulations (e.g., Gillet et al., 2017; Onodera et al., 2022), and the contribution of heterogeneous media in the lunar crust, such as megaregolith, has been understood better. On the other hand, the influence of topography (e.g., surface craters, mantle plugs) has less been discussed. While the Apollo landing sites (especially Apollo 12 & 14) are relatively flat, the far side or polar regions host large topographic features, such as basins, which can strongly affect the seismic wave propagation and, therefore, the estimation of interior structure.
In this study, I numerically simulated impact-induced seismic waves occurring on Szilard crater located on the far side of the Moon, where many craters and a subsurface mantle plug coexist. In the presentation, I will show preliminary results of how lunar topographic features, in addition to megaregolith, affect seismic wave propagation and discuss what kind of seismic observations are preferred to illuminate the detailed crustal structure.
References:
Blanchette-Guertin et al. (2012), JGR, 117 (E6), E06003.
Gillet et al. (2017), PEPI, 262, 28-40.
Onodera et al. (2022), JGR: Planets, 127 (12), e2022JE007558.