The epicenter of one of the strongest moonquakes ever recorded by the Apollo Passive Seismic Experiment could not be accurately determined. Researchers tracked multiple possible locations using a relocation algorithm specifically adapted for the sparse seismic networks near the Pole. Blue boxes show locations of proposed Artemis III landing regions, while the small red marks represent scarps. Image credit: NASA/ LRO/ LROC/ASU/ Smithsonian Institution

New research indicates that potential landing sites at the Moon’s south pole for robotic and human-carrying Artemis missions are vulnerable to quakes and landslides.

Science results published in the Planetary Science Journal show linkage of a group of faults located in the Moon’s south polar region to one of the most powerful moonquakes recorded by seismometers planted by Apollo moonwalkers over 50 years ago.

Image credit: NASA

Active thrust faults

“The potential of strong seismic events from active thrust faults should be considered when preparing and locating permanent outposts and pose a possible hazard to future robotic and human exploration of the south polar region,” explains the paper, lead by Thomas Watters, a senior scientist emeritus in the National Air and Space Museum’s Center for Earth and Planetary Studies.

“Our modeling suggests that shallow moonquakes capable of producing strong ground shaking in the south polar region are possible from slip events on existing faults or the formation of new thrust faults,” said Watters in a University of Maryland press statement.

Rendering of Artemis astronauts exploring a lunar south pole crater. A water ice-rich resource ready for processing?
Image credit: NASA

Landslides from seismic shaking

Nicholas Schmerr, a co-author of the paper and an associate professor of geology at the University of Maryland, said this means that shallow moonquakes can devastate hypothetical human settlements on the Moon, in the university statement.

The research team made use of computer models to simulate the stability of surface slopes in the south pole region, finding some areas were particularly vulnerable to landslides from seismic shaking.

“As we get closer to the crewed Artemis mission’s launch date, it’s important to keep our astronauts, our equipment and infrastructure as safe as possible,” Schmerr said in the university release.

“This work is helping us prepare for what awaits us on the Moon,” Schmerr adds, “whether that’s engineering structures that can better withstand lunar seismic activity or protecting people from really dangerous zones.”

Apollo 11 astronaut Buzz Aldrin with deployed seismic experiment.
Image credit: NASA

Magnitude 5 moonquake

Unlike earthquakes here on Earth that tend to last only a few seconds or minutes, shallow moonquakes can last for hours and even a whole afternoon, the researchers report.

The magnitude 5 moonquake recorded by the Apollo Passive Seismic Network in the 1970s was connected to a group of faults found by NASA’s Lunar Reconnaissance Orbiter (LRO) more recently. 

The research paper concludes: “The potential of strong seismic events from active thrust faults should be considered when preparing and locating permanent outposts and pose a possible hazard to future robotic and human exploration of the south polar region.”

For access to the paper in the Planetary Science Journal – “Tectonics and Seismicity of the Lunar South Polar Region” – go to:

https://iopscience.iop.org/article/10.3847/PSJ/ad1332/pdf

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