The team then superimposed this location data onto the LRO imagery of the thrust faults.
"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 reads.
The Moon is one place we know that experiences those kinds of shifts, and new research suggests that it might actually be making the Moon smaller over time.
The scientists detailed their findings online today (May 13) in the journal Nature Geoscience. They will need to take the potential for moonquakes into consideration by avoiding landing near or building any permanent structures on particularly "active" areas, Watters says. But the lunar faults, like Earth's own fault lines, are similar in that occur where pieces of the surface sometimes rub against each other, causing quakes that can reverberate throughout the planet.
The moonquakes were recorded by five seismometers that were placed on the Moon's surface during the Apollo 11, 12, 14, 15 and 16 missions.
This means that the Apollo seismometers recorded the moon shrinking, the researchers said. On Earth, the quakes would have ranged in magnitude from about 2 to 5.
Using the revised location estimates from the new algorithm, the team found that eight of the 28 shallow quakes were within 30 kilometers (18.6 miles) of faults visible in lunar images. Additionally, while other events, such as meteoroid impacts, can produce quakes, they produce a different seismic signature than quakes made by fault slip events.
"Some of these quakes can be fairly strong, around five on the Richter scale."Some of the quakes also happened during a point in the moon's orbit when it was farthest from Earth, indicating that the tidal stress of Earth's gravity could have contributed to stress on the moon's crust".
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. As the Moon cools on the inside, the Moon's outside "wrinkles" and "shrivels" like a dehydrated grape when it turns into a raisin.
These moonquakes likely happen because the moon is quivering as it shrinks, researchers added.
This results in faults on the surface where one section of crust is pushed up over an adjacent section.
"It is truly incredible that the datasets collected by the astronauts so many years ago are still yielding new scientific findings about our moon", Schmerr said. For example, the Apollo missions detected about 11,000 moonquakes happening about 500 to 680 miles (800 to 1100 kilometers) beneath the lunar surface. With a larger network of modern seismometers, we could make huge strides in our understanding of the Moon's geology.
This release is adapted from text provided by NASA's Goddard Space Flight Center.
The research also sheds some light on the moon's internal composition.
The College of Computer, Mathematical, and Natural Sciences at the University of Maryland educates more than 9,000 future scientific leaders in its undergraduate and graduate programs each year.