A thrust fault (indicated by arrows) crosses the Taurus-Littrow valley where the Apollo 17 mission landed (asterisk) in 1971. Moonquake indicators include material from a landslide visible at one end of the fault (1); boulder tracks on a nearby slope (2); and areas where fresh soil has been exposed (3). Image: NASA/GSFC/Arizona State University/Smithsonian
Data from seismometers left on the Moon by Apollo astronauts, a new technique for analysing the data they produced and detailed images captured by NASA’s Lunar Reconnaissance Orbiter show the moon is still shrinking as its interior slowly cools, triggering thrust faults where one section of crust is pushed over another.
In a paper published in Nature Geoscience, researchers conclude the Moon has shrunk by about 50 metres (150 feet) over the past several hundred million years.
“Our analysis gives the first evidence that these faults are still active and likely producing moonquakes today as the Moon continues to gradually cool and shrink,” said Thomas Watters, senior scientist in the Center for Earth and Planetary Studies at the Smithsonian’s National Air and Space Museum in Washington. “Some of these quakes can be fairly strong, around five on the Richter scale.”
Five Apollo crews – missions 11, ...