Ground motion amplification due to lunar topography

Abstract

<p>In recent years, estimating the possible ground motion on the Moon became quite essential as various researchers are exploring safe extra-terrestrial habitats close to the Earth. From the high-resolution imageries, it is observed that seismic sources like lobate scarps and wrinkle ridges are identified representing that there is seismic activity on the Moon which is considered a hazard to the lunar base. Therefore, it is essential to include topographic amplification factors in the ground motion predictions on the Moon which are in turn used in the seismic hazard analysis. It is well known that there is a wide variation of topographical features in the lunar south pole region (LSPR). Hence in this study, the spectral element method is preferred to model the seismic wave propagation in such complex topographic regions. The main objective of this study is to estimate the ground motion amplification on the Artemis landing sites that are present in the LSPR region. The topography for the study region is extracted from the entire South-pole topographic map which is obtained from the LRO-LOLA. A grid elevation data is incorporated with a resolution of 30m. The shallow moonquake event that occurred on March 13, 1973, is considered a seismic source, located at [84⁰ S, 134⁰ W] and has a focal depth of 5 km. The seismic wave simulations can generate up to a frequency of up to 2Hz from the developed model. The simulations have been performed with and without topography. The amplification ratio i.e., Peak ground displacement with topography/ Peak ground displacement without topography is calculated for the considered landing sites. In addition, an amplification map of the shake intensity maps is also generated for the considered study region. Results show that there is amplification on ridges and de-amplification in the valleys.</p>