moonquakes


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moonquakes

Localized disturbances inside the Moon, detected by the Apollo seismic network. Rare but strong moonquakes occur 50–300 km below the surface, although they are much less intense than earthquakes by a factor of about 1000. Weaker but more numerous moonquakes occur at depths of 800–1000 km and are triggered at perigee by lunar tides. Seismic signals on the Moon are extended by scattering in the dry and porous lunar crust. Deep moonquakes provide information, through their arrival times, of the structure of the lunar interior: a 60 km crust on average, a mantle extending to a depth of 1100 km or more, and a central partly molten core roughly 500–600 km in radius.