In 2010, Nasa with reports from its Lunar Reconnaissance Orbiter revealed that the Moon is experiencing quakes as its interior is cooling, this in turn is causing the moon to shrink and is leaving thousand of cliffs called the thrust faults on the surface.
But that happened in 2010 and why bring it up now — that’s because a new report suggests that the moon is still experiencing quakes, with the shrinking also active. Nicholas Schmerr, professor at University of Maryland, along with a team of researchers designed a new algorithm to analyse the seismic data from the Moon.
With this new algorithm in place, the team was able to find even more accurate epicentres of previous moonquakes and when they superimposed this location data onto a the LRO thrust fault imagery, they found 8 of the total 28 analysed quakes to have been occurred from true tectonic activity.
Although, the instruments that recorded these quakes were retired in 1977, but the team says that quakes on the Moon are probably still active today. These instruments were placed on the Moon’s surface by the Apollo 11, 12, 14, 15 and 16 missions, of-them the Apollo 11 seismometer was only active for a month but the other remained functional and recorded 28 shallow quakes.
“We found that a number of the recorded quakes occurred very close to the faults seen in the LRO imagery,” said Nicholas Schmerr. Further adding, “It’s quite likely that these faults are still active today. Also, on Earth you don’t get to see the active tectonic movement, so it’s quite interesting to think that thesis faults may still be producing Moonquakes.”
According to the results of the new Moonquake algorithm, 8 of the quakes occurred within 19 miles of the visible fault lines in the LRO imagery — close enough for the team to blame the faults. Also, six of these happened when the Moon was at its farthest from the Earth — a time when the Moon’s surface experiences peak stress by Earth’s gravity — thus making thrust faults more active.
Thomas Watters, lead author of the study and senior scientist at the Center for Earth and Planetary Studies at Smithsonian Institution in Washington , said “We think that these eight quakes were caused due to the faults slipping as the Moon experienced a combined stress by global contraction and tidal forces“.
Since 2009, the LRO has imaged as many as 3500 faults, of which some show landslides running along them. The moon here can be compared to a raisin, which shrinks as it dries, but as surface of the Moon is more brittle, it cracks as the interior shrinks.
The faults still active isn’t just an imagination, there is some evidence in terms of LRO images. Some images contain fresh tracks of boulders running down cliffs. Although, on the Moon, these tracks are erased relatively quickly by the constant micrometeoroid rain, but the team with access to a decade long LRO data will likely compare images of the fault regions — from what they were to what they are now.