Our shrinking Moon could cause moonquakes near the Artemis astronauts’ landing site

When plotting sites for crewed lunar landings, mission planners must account for many lunar parameters. The shape of the terrain could make or break a mission, and a possible high volume of buried water could make one spot much more tantalising than its drier counterpart. But geologists suggest it’s also important to keep moonquakes and lunar landslides in mind. Researchers examining the Moon’s south polar region – which sits near the planned landing side of Artemis III, set to touch down in 2026 – have identified fault lines whose slips triggered a major moonquake about 50 years ago. Certain Apollo missions carried seismometers. On 13 March 1973, a particularly strong moonquake rattled those seismometers from the general direction of the Moon’s south pole. Decades later, the Lunar Reconnaissance Orbiter flew over the south pole and discerned a webwork of fault lines. With new models, researchers have connected those faults with that moonquake. The research adds to our picture of what moonquakes are like in general. In principle, moonquakes are like earthquakes. Both are caused by shifting faults; in the Moon’s case they’re caused by creases that form on the Moon’s surface as it shrinks due to its interior cooling over the last few hundred million years. It’s sort of like a raisin shrivelling up, which also helps us visualise the creation of those creases.

Further, the Moon’s surface is much less tightly packed than Earth’s, often consisting of loose particles that can be thrown up and strewn about by impacts. As a result, moonquakes are even more likely to trigger landslides than earthquakes are. According to the researchers, as the day when human boots tread the Moon yet again draws nearer, the humans in question will have to plan for the possibility that the ground under those boots is not as stable as they might hope. The researchers’ model suggests, for example, that the walls of Shackleton crater, famed for its ice, are vulnerable to landslides.