Published in Science Advances, the study was co-authored by Smithsonian Senior Scientist Emeritus Thomas R. Watters and University of Maryland geophysicist Nicholas Schmerr. Their analysis focused on geological features left behind by seismic activity, revealing insights into the strength and frequency of these moonquakes.

"We don't have the sort of strong motion instruments that can measure seismic activity on the moon like we do on Earth, so we had to look for other ways to evaluate how much ground motion there may have been, like boulder falls and landslides that get mobilized by these seismic events," Schmerr said.

The team determined that quakes near magnitude 3.0 occurred repeatedly along the Lee-Lincoln fault over the past 90 million years. Although minor by terrestrial standards, such quakes could be hazardous if close to lunar infrastructure. The findings suggest the Lee-Lincoln fault remains potentially active, raising concerns about the placement of future lunar bases.

"The global distribution of young thrust faults like the Lee-Lincoln fault, their potential to be still active and the potential to form new thrust faults from ongoing contraction should be considered when planning the location and assessing stability of permanent outposts on the moon," Watters said.

Watters and Schmerr calculated a one-in-20-million daily chance of a damaging moonquake near an active fault. Over long missions, this risk becomes non-negligible. Schmerr explained that while short-term stays like Apollo 17 carried minimal risk, missions lasting years or decades face growing exposure.

"It doesn't sound like much, but everything in life is a calculated risk," Schmerr noted. "The risk of something catastrophic happening isn't zero, and while it's small, it's not something you can completely ignore while planning long-term infrastructure on the lunar surface."

The implications are critical for future programs like Artemis, especially for missions using tall, slender landers such as Starship. Schmerr emphasized that expanding lunar paleoseismology-using geological evidence to infer ancient moonquakes-will be vital for safe exploration.

"If astronauts are there for a day, they'd just have very bad luck if there was a damaging event," Schmerr added. "But if you have a habitat or crewed mission up on the moon for a whole decade, that's 3,650 days times 1 in 20 million, or the risk of a hazardous moonquake becoming about 1 in 5,500. It's similar to going from the extremely low odds of winning a lottery to much higher odds of being dealt a four of a kind poker hand."

Future Artemis missions are expected to provide new seismic data with modern instruments far more advanced than those used during Apollo. These tools will support researchers in refining hazard maps and helping NASA avoid high-risk zones.

"We want to make sure that our exploration of the moon is done safely and that investments are made in a way that's carefully thought out," Schmerr said. "The conclusion we came to is: don't build right on top of a scarp, or recently active fault. The farther away from a scarp, the lesser the hazard."

Research Report:Paleoseismic activity in the moon's Taurus-Littrow valley inferred from boulder falls and landslides

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