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The moon is shrinking, causing landslides and moonquakes exactly where NASA wants to build its 1st lunar colony

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The moon has been slowly shrinking for millions of years. Now, as Artemis 3 nears its 2026 launch date, geologists worry about whether moonquakes and lunar landslides will impact landing.

A photograph of the moon's surface.
A photograph of the moon's surface. (Image credit: NASA)

When plotting sites for crewed lunar landings — ranging from the forthcoming Artemis missions to eventual lasting moon settlements — mission planners must account for tons of lunar parameters. For instance,  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 tantalizing than its drier counterpart. But now, geologists suggest it's also important to keep moonquakes and lunar landslides in mind.

As the scientists emphasize, this is no longer an academic question. Researchers examining the moon's south polar region — which sits near the planned landing side of Artemis 3, 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 along with them. On March 13, 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.

Related: Humanity's future on the moon: Why Russia, India and other countries are racing to the lunar south pole

The research further 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. If you're asking yourself why in the world the moon would be shrinking, well, it's basically because the lunar interior has cooled over the last few hundred million years. It's sort of like a raisin shriveling up, scientists say, which also helps us visualize the creation of those creases.

The epicenter of one of the strongest moonquakes recorded by the Apollo Passive Seismic Experiment was located in the lunar south polar region. However, the exact location of the epicenter could not be accurately determined. A cloud of possible locations (magenta dots and light blue polygon) of the strong shallow moonquake using a relocation algorithm specifically adapted for very sparse seismic networks are distributed near the pole. Blue boxes show locations of proposed Artemis III landing regions. Lobate thrust fault scarps are shown by small red lines. The cloud of epicenter locations encompasses a number of lobate scarps and many of the Artemis III landing regions. (Image credit: NASA/LROC/ASU/Smithsonian Institution)

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.

A Lunar Reconnaissance Orbiter Camera, Narrow Angle Camera (NAC) mosaic of the Wiechert cluster of lobate scarps (left pointing arrows) near the lunar south pole. A thrust fault scarp cut across an approximately 1-kilometer (0.6-mile) diameter degraded crater (right pointing arrow).

A Lunar Reconnaissance Orbiter Camera, Narrow Angle Camera (NAC) mosaic of the Wiechert cluster of lobate scarps (left pointing arrows) near the lunar south pole. A thrust fault scarp cut across an approximately 1-kilometer (0.6-mile) diameter degraded crater (right pointing arrow). (Image credit: NASA/LRO/LROC/ASU/Smithsonian Institution)
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"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," said Nicholas Schmerr, a geologist and one of the researchers, in a statement. "This work is helping us prepare for what awaits us on the moon — whether that’s engineering structures that can better withstand lunar seismic activity or protecting people from really dangerous zones."

The research was published on Jan. 25 in The Planetary Science Journal.

Originally posted on Space.com.

Rahul Rao

Rao is a freelance science journalist based in New York and is a contributor to Live Science’s sister site Space.com, as well as Popular Science, EEE Spectrum and Gizmodo. Rao has a bachelor’s degree in Physics and English from Vanderbilt University, and a master’s degree in Science, Health and Environmental Reporting from New York University.