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Tuesday, 14 May 2019

The moon is quaking as it shrinks

[S.O.T.T]: A 2010 analysis of imagery from NASA's Lunar Reconnaissance Orbiter (LRO) found that the moon shriveled like a raisin as its interior cooled, leaving behind thousands of cliffs called thrust faults on the moon's surface.

A new analysis suggests that the moon may still be shrinking today and actively producing moonquakes along these thrust faults. A team of researchers including Nicholas Schmerr, an assistant professor of geology at the University of Maryland, designed a new algorithm to re-analyze seismic data from instruments placed by NASA's Apollo missions in the 1960s and '70s. Their analysis provided more accurate epicenter location data for 28 moonquakes recorded from 1969 to 1977.

The team then superimposed this location data onto the LRO imagery of the thrust faults. Based on the quakes' proximity to the thrust faults, the researchers found that at least eight of the quakes likely resulted from true tectonic activity-the movement of crustal plates-along the thrust faults, rather than from asteroid impacts or rumblings deep within the moon's interior.

Although the Apollo instruments recorded their last quake shortly before the instruments were retired in 1977, the researchers suggest that the moon is likely still experiencing quakes to this day. A paper describing the work, co-authored by Schmerr, was published in the journal Nature Geoscience on May 13, 2019.

"We found that a number of the quakes recorded in the Apollo data happened very close to the faults seen in the LRO imagery," Schmerr said, noting that the LRO imagery also shows physical evidence of geologically recent fault movement, such as landslides and tumbled boulders. "It's quite likely that the faults are still active today. You don't often get to see active tectonics anywhere but Earth, so it's very exciting to think these faults may still be producing moonquakes."...read more>>>...

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