Blending Apollo-era and LRO Data and New Technologies to Assess Seismic Hazards on the Moon

Abstract:

As NASA and other organizations look toward the Moon under planned lunar exploration programs, it is important to understand the hazards posed to the structures and instruments that will perform important scientific missions and support the health and safety of astronauts. Available data indicates that the Moon is seismically active with the potential to produce significant moonquakes. Probabilistic seismic hazard assessment (PSHA) has been widely adopted to assess the frequency and severity of ground shaking on Earth and is used to inform a range of engineering decisions. It provides a systematic framework for characterizing and including random variabilities and epistemic uncertainties in the assessment of seismic hazards.

In this study, we explore the application of PSHA methods to assess seismic hazards on the Moon, with a particular focus on high-frequency teleseismic (HFT) events (shallow moonquakes). While available data related to lunar seismic hazards is limited relative to Earth, the blending of Apollo-era and Lunar Reconnaissance Orbiter (LRO) data with new technologies provides us with the building blocks necessary to construct a lunar PSHA for selected sites on the Moon.

Looking to the past, we leverage data from the Apollo seismic stations, which recorded ground motion data from 28 shallow moonquakes. We seek to use this data to establish models related to event magnitudes and to characterize shear wave velocities. This information is coupled with more recent data from LRO and mapping efforts that provide new insights regarding fault locations and surface geometry. Further, by coupling high-fidelity numerical models with a growing knowledge of fault characteristics and lunar topography, we can begin to model ground motion for moonquakes. While high-fidelity numerical models are computationally expensive, machine-learning derived surrogate modelling techniques present an opportunity to balance computational costs and prediction capabilities. In this work, we describe our ongoing efforts to build a preliminary PSHA framework for the Moon. We provide updates on study progress, outline challenges, and describe insights of relevance to hazard characterization and potential knowledge gaps that can be addressed through future missions.