Moon Is Shrinking With 10,000 Faults & Moonquakes: Know What They Are, Why Scientists Are Concerned & Impact on Earth

The Moon is slowly shrinking as its interior cools, creating cracks, ridges, and about 10,000 faults across its surface, according to Scientists who are reviewing these geological changes to understand the Moon’s evolution and potential risks for Earth. Although the discovery of thousands of faults has ignited concerns, there is no proof that the shrinking Moon poses an immediate threat to Earth.

Unlike Earth, the Moon has no active system of plate tectonics. However, it is not geologically dead. As its interior loses heat over billions of years, the Moon contracts, triggering its rocky outer crust to buckle and break, which triggers geological features known as thrust faults as one section of the crust shifts over another.

NASA researchers state that if the rate of radius decrease has stayed constant over the past 400 million to 800 million years, the Moon has likely been reducing about 2.3 to 4.3 inches per million years, or about 39 millionths of an inch per year.

Why Are Scientists Concerned About 10,000 Faults & Moonquakes on the Moon?

The discovery and mapping of thousands of small lunar faults emphasise how active the Moon’s surface can be. These structures are crucial because movements along faults can trigger moonquakes, some of which may be strong enough to threaten equipment and infrastructure.

The Moon sees varied seismic activity, including quakes caused by tidal forces from Earth, meteorite impacts, and changes within its interior. Shallow moonquakes are especially relevant to future exploration because they can last longer than many earthquakes on Earth, especially due to the Moon’s dry, fractured crust.

For astronauts planning to create long-term bases, these findings matter. Habitats, landing sites, power systems, and scientific instruments will need to be positioned and developed with lunar seismic hazards.

What Will the Shrinking Moon Mean for Earth?

The pressing question is whether the Moon’s shrinking could impact life on Earth. Scientists have found no evidence that this slow contraction poses an immediate threat to our planet. The changes occurred over millions of years and are far too slow to cause sudden disruptions to Earth's environment.

The Moon's gravity plays an integral role in producing ocean tides and stabilises Earth's axial tilt, which impacts long-term climate patterns. However, the Moon's contraction does not imply it is disappearing or instantly losing its gravitational impact. Its overall size is shifting only slightly. 

The Moon is also slowly shifting away from Earth at around 3.8 centimetres per year. This is a different process from shrinking and is triggered by gravitational interactions between Earth and the Moon. Over very long periods, this movement can trigger tides and affect the length of Earth's days, but it is not a massive concern yet.