April 7, 2006
As NASA envisions it, astronauts will return to the moon within the next decade or so. Unlike in the earlier, quick, Apollo visits, these astronauts will build a permanent base and prepare for an historic undertaking that will send explorers to Mars. As Clive Neal, associate professor of civil engineering and geological sciences at the University of Notre Dame, envisions it, these same astronauts may be in for a shocking — and rocking — surprise.
Neal and a team of 15 other planetary geologists have reexamined data from seismometers placed by Apollo astronauts at lunar landing sites from 1969 to 1972. They found that instruments from Apollo missions 12, 14, 15 and 16 consistently radioed back seismic data to Earth until they were turned off in 1977 in a NASA cost-cutting measure.
Neal and his colleagues discovered a surprising number of relatively large “moonquakes,” including some that lasted a remarkably long time.
“The moon is seismically active,” Neal said. “When a quake occurs, the moon rings like a bell.”…