The 6.7-magnitude earthquake that jolted Hawaii this past October lasted about a minute, but on
the moon a similar quake might continue shaking for several minutes, according to Clive Neal,
ND associate professor of civil engineering and geological sciences.
"Most earthquakes last a minute or two. Shallow moonquakes can last up to 10 minutes,"
says the Notre Dame geologist, who is part of a research team assessing quakes' effect on any
potential manned moon base.
Data for the study came from seismometers placed on the moon between 1969 and 1972
that recorded more than 12,000 seismic events until they stopped transmitting date in 1977.
Using those seismometer readings, Neal and his colleagues identified four main forms of
moonquake: those caused by a meteorite impact; "deep moonquakes" that result from events 700
kilometers below the surface; "shallow quakes" that ripple out from events 20 to 30 kilometers
below the surface; and "thermal moonquakes" that are generated by the sudden increase in
temperature at moon dawn when the sun's rays heat the moon surface.
(January 2007)
