You are using an older browser version. Please use a supported version for the best MSN experience.

Moon appears to be active below the surface, scientists say

The Washington Post logo The Washington Post 5 days ago Reuters
This mosaic of many images taken by NASA’s Lunar Reconnaissance Orbiter shows wrinkle ridges in a region of the Moon called Mare Frigoris.  These ridges add to evidence that the moon has an actively changing surface. © Ho/AFP/Getty Images This mosaic of many images taken by NASA’s Lunar Reconnaissance Orbiter shows wrinkle ridges in a region of the Moon called Mare Frigoris. These ridges add to evidence that the moon has an actively changing surface.

The moon may be dynamic and tectonically active like Earth based on a new analysis revealed Monday of quakes measured by seismometers on the moon from 1969 and 1977.

Researchers examining the seismic data gathered during NASA’s Apollo missions traced the location of some of the quakes to step-shaped cliffs called scarps on the lunar surface that formed relatively recently, in geological terms, because of the ongoing shrinking of the moon as its hot interior cools.

“It means that the moon has somehow managed to remain tectonically active after 4.51 billion years,” said Smithsonian Institution planetary scientist Thomas Watters, who led the research published in the journal Nature Geoscience.

Earth’s tectonic activity is driven by its hot interior. The moon, which orbits our planet at a distance of about 239,000 miles, has a diameter of about 2,160 miles, a bit more than a quarter of Earth’s diameter.

Images from NASA’s Lunar Reconnaissance Orbiter showed that the moon has delicately shriveled as its interior has cooled over the eons, like a plump grape transforming into a smaller raisin. As a result, it has acquired thousands of small surface wrinkles in the form of surface features called thrust-fault scarps.

Related Slideshow: An exploration of the planets in our Solar System (Provided by Photo Services)

These faults push one part of the lunar crust up and over the adjoining part, said University of Maryland geologist and study co-author Nicholas Schmerr. They can reach up to about 330 feet tall and extend for many miles.

“This is exciting as it wasn’t clear if the moon had already gone through this period billions of years ago and was tectonically dead, or if it was still active in the present,” Schmerr said.

U.S. astronauts placed seismometers on the lunar surface during the Apollo 11, 12, 14, 15 and 16 missions, recording 28 shallow quakes up to almost 5 magnitude, which is moderate strength. Eight quakes occurred close to faults. Other events such as meteorite impacts can produce quakes, but those would produce different seismic signatures.

Boulder movements and disturbed soil near the scarps also indicated tectonic activity.

Watters said experts must be mindful that quakes may strike near these scarps when planning sites for future lunar exploration and a long-term human presence on the moon.

The moon is not the solar system’s only object shrinking with age. The innermost planet, Mercury, boasts many thrust faults. 

More From The Washington Post

The Washington Post
The Washington Post
image beaconimage beaconimage beacon