Quakes show that moon, gradually shrinking,is tectonically active

  • Tuesday 14, May 2019 09:06 AM
  • Quakes show that moon, gradually shrinking,is tectonically active
Sharjah 24 – Reuters: The moon may be dynamic and tectonically active like Earth - not the inert world some scientists had believed it to be - based on a new analysis disclosed on Monday of quakes measured by seismometers in operation 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, due to the ongoing subtle 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 (385,000 km), has a diameter of about 2,160 miles (3,475 km), 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, akin to 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.

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 (100 meters) tall and extend for many miles (km).