The data collected during the Apollo seismic experiments can provide important information regarding the lunar subsurface conditions and the corresponding mechanical properties. This paper aims to determine the shear wave velocity of the shallow subsurface using an elastodynamic space-time spectral element forward solver and the trust region reflective algorithm for back-calculation. The elastodynamic forward solver provides a semi-analytical solution for the wave propagation through subsurface materials. The trust region reflective algorithm is a bounded non-linear least square algorithm that effectively reduces the difference (Euclidean distance) between measured and predicted data by iteratively improving the prediction of material properties. In this paper, the seismic data is used to generate a dispersion image of the lunar subsurface, which provides the relation between the phase (group) velocity and frequency. Such dispersion images can be used to derive the shear wave velocity in each layer.

Access the Conference Proceedings Paper on ASCE Library 

The data collected during the Apollo seismic experiments can provide important information regarding the lunar subsurface conditions and the corresponding mechanical properties. This paper aims to determine the shear wave velocity of the shallow subsurface using an elastodynamic space-time spectral element forward solver and the trust region reflective algorithm for back-calculation. The elastodynamic forward solver provides a semi-analytical solution for the wave propagation through subsurface materials. The trust region reflective algorithm is a bounded non-linear least square algorithm that effectively reduces the difference (Euclidean distance) between measured and predicted data by iteratively improving the prediction of material properties. In this paper, the seismic data is used to generate a dispersion image of the lunar subsurface, which provides the relation between the phase (group) velocity and frequency. Such dispersion images can be used to derive the shear wave velocity in each layer.

**[Access the Conference Proceedings Paper on ASCE Library](https://doi.org/10.1061/9780784483374.010)** 

Apollo Seismic Data Interpretation Using an Elastodynamic Space-Time Spectral Element Technique and Dispersion Image Inversion Method

This conference brought the experience and knowledge of experts in the aerospace industry together to share and discuss the latest research and engineering techniques that effect the exploration and settlement of space. Presentations were made in multiple concurrent symposia over three days. Topics included: Granular materials in space exploration, exploration in utilization of extra-terrestrial bodies, advanced materials and designs for aerospace and terrestrial structures under extreme environment, structures in challenging environments, and space engineering, construction, and architecture for the moon, Mars, and beyond.

Due to challenges with COVID-19, this 17th Biennial was moved to April 2021 and was offered in a virtual format.

[Paper Proceedings](https://ascelibrary.org/doi/book/10.1061/earthandspace2021)

Conference DOI: https://doi.org/10.26226/m.63243a3fb7ff860013acd57f