A new research study found that the moon is quite seismologically active satellite, given that it experiences lunar quakes, often called “moonquakes.” However, the study found that moonquakes are causing the moon to shrink, shocking scientists who don’t know what’s causing the seismic activity.
Researchers studied 28 recorded moonquakes which took place between 1969 and 1977. Their analysis revealed that eight of the moonquakes arose from what researchers called “true tectonic activity – the movement of crustal plates.” The others resulted from asteroids and rumblings inside the moon.
“We found that a number of the quakes recorded in the Apollo data happened very close to the faults seen in the [NASA’s Apollo and Lunar Reconnaissance Orbiter missions] LRO imagery,” University of Maryland assistant professor Nicholas Schmerr said in a statement. “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.”
Researchers used data recorded by five seismographs placed on the moon’s surface during the Apollo 11, 12, 14, 15 and 16 missions. Those quakes would have registered between a 2 and a 5 on the Moment Magnitude Scale if they had happened on Earth.
“We think it’s very likely that these eight quakes were produced by faults slipping as stress built up when the lunar crust was compressed by global contraction and tidal forces, indicating that the Apollo seismometers recorded the shrinking moon and the moon is still tectonically active,” lead author Thomas Watters said in the statement.
NASA first saw evidence that the moon is shrinking in 2010 in images from the Lunar Reconnaissance Orbiter. Researchers then used data from the 1960s and 1970s to accompany the 2010 data and created an algorithm which could explain what caused the quakes which have been shrinking the moon.
Thanks to the algorithm and the data it provided, the moon can be called “tectonically active.” The findings of this research were published in the journal Nature Geoscience. The research offers an explanation for seismic and tectonic movement on the moon. However, researchers still need to find evidence of what’s causing it. Perhaps future lunar missions will provide more information.
“We conclude that the proximity of moonquakes to the young thrust faults together with evidence of regolith disturbance and boulder movements on and near the fault scarps strongly suggest the Moon is tectonically active,” the study’s abstract states.
“For me, these findings emphasize that we need to go back to the moon,” Schmerr added. “We learned a lot from the Apollo missions, but they really only scratched the surface. With a larger network of modern seismometers, we could make huge strides in our understanding of the moon’s geology. This provides some very promising low-hanging fruit for science on a future mission to the moon.”