Re-evaluation of Apollo 17 Lunar Seismic Profiling Experiment data including new LROC-derived coordinates for explosive packages 1 and 7, at Taurus-Littrow, Moon

Abstract

We re-analyze data from the Apollo 17 Lunar Seismic Profiling Experiment (LSPE) using updated locations of the applied explosive sources. Specifically, we complement our models with the previously missing coordinates and P-wave arrival times of Explosive Packages EP1 and EP7. We read new P-arrival times for all eight EP events, and solve for two- and three-layer seismic velocity models. We confirm a strong increase of seismic velocity with depth. In particular, we suggest a more drastic increase than was previously thought from post-mission coordinate information. For the three-layer model we find P-wave velocities of 315, 580, and 2680 ​m/s for the uppermost, second, and third layers respectively, with the transitions between the layers being at depths of 110 and 855 ​m. When compared with previous results, we find (1) a slightly higher velocity (+10.5%) for the uppermost layer, (2) no differences in velocity for the second layer, and a (3) significantly higher P-wave velocity for the third layer (+46.9%).