What does moonquake mean?
A moonquake is a seismic event occurring within the Moon, analogous in general principle to an earthquake but on a body with very different geology and seismic behavior. Lunar tremors can be shallow or deep and may be caused by the expansion and contraction of the Moon as its surface undergoes extreme temperature changes, by tidal stresses from Earth, by motion deep within the lunar interior, or by meteoroid impacts. The term became especially important during the Apollo missions, when astronauts left seismometers on the lunar surface to measure vibrations and thereby investigate the Moon's internal structure. In current scientific use, moonquake chiefly refers to seismic activity itself, although some writers also use the alternative expression lunar quake. It is a technical term rather than part of ordinary conversation, and its principal value lies in explaining the Moon's active and surprising inner world.
nounA seismic event caused by movement or vibration within the Moon. Moonquakes may result from tidal stresses, thermal changes, deep Moon activity, or impacts from meteoroids and other objects.
- Any seismic event occurring within or on the Moon.
"The seismometer recorded a moonquake as the spacecraft's ascent stage struck the lunar surface."
"Scientists analyzed the seismic signal to determine the depth and origin of the moonquake."
"A meteoroid impact generated a moonquake that was detected by a lunar seismometer."
The regular plural is used when referring to multiple recorded or observed lunar seismic events.
"The seismometers recorded several moonquakes during the mission."
Moonquakes are not merely Earthquakes on another world: Apollo-era seismometers revealed several distinct kinds of lunar tremors, including deep events and vibrations caused by meteoroid impacts.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of moonquake
Moonquake is a modern compound of moon and quake, both elements being of Germanic origin. Moon continues Old English mōna, while quake derives from Old English cwacan, meaning 'to shake, tremble, or move violently.' The compound was adopted in the context of lunar science as instruments began recording seismic activity on the Moon.
How moonquake is actually used
This is a specialized scientific and astronomical term. It is normally singular or plural, with the plural formed by adding -s; in technical writing, the alternative form 'lunar quake' is also encountered.