Moonquakes Can Shake the Moon for More Than 10 Minutes

The Moon has moonquakes that can last more than 10 minutes, caused by tidal forces, cooling and shrinking rock, impacts, and temperature changes.

Astronomy

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The Moon is not as quiet beneath its surface as it looks from Earth. Seismometers placed on the lunar surface during the Apollo era detected several kinds of moonquakes. Some deep quakes are linked to Earths gravity tugging on the Moon, while others happen because the Moon is slowly cooling and shrinking. As the interior cools, the brittle outer crust can crack and move along faults. Meteorite impacts can also send seismic waves through the Moon, and extreme temperature changes between lunar night and day can make shallow rocks expand and contract. Cooling-related moonquakes can begin roughly 20 to 30 kilometers below the surface, reach about magnitude 5.5, and last for more than 10 minutes. NASA also reports that the Moon has become roughly 50 meters smaller in diameter over the last several hundred million years, showing that its slow contraction is still written into the lunar landscape. The long-lasting vibrations are partly related to the Moon being dry and fractured, which allows seismic energy to persist differently than it does on Earth.

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