“A moonquake is the lunar equivalent of an earthquake. They were first discovered by the Apollo astronauts. Moonquakes are much weaker than earthquakes. According to NASA, there are at least four different kinds of moonquakes:
The first three mentioned above tend to be mild; however, shallow moonquakes can register up to 5.5 on the Richter scale. Between 1972 and 1977, twenty-eight shallow moonquakes were observed. On Earth, quakes of magnitude 4.5 and above can cause damage to buildings and other rigid structures.”