Earthquakes Happen On The Moon

When the Apollo astronauts placed scientific instruments on the lunar surface, they uncovered a surprisingly active world. For years after the missions ended, seismometers relayed data to Earth, revealing that the Moon experiences thousands of seismic events annually. These "moonquakes" provided the first real glimpse into the Moon's interior, proving it wasn't the silent, geologically dead sphere many had assumed.

The sources of these tremors are quite different from our own. Many are deep quakes, occurring about 700 kilometers below the surface, caused by the immense tidal forces from Earth’s gravity literally squeezing and stretching the Moon’s core. More powerful and mysterious are the shallow quakes, which can be as strong as a moderate earthquake on Earth. Because the Moon’s crust is cold, rigid, and completely dry, it lacks the water (Review) that dampens seismic waves on our planet. As a result, the vibrations from a strong moonquake can continue for over ten minutes, causing the entire Moon to ring like a bell.