The moon may be tectonically active

> The discovery of young thrust faults on the Moon is evidence of recent tectonic activity, but how recent is unknown. Seismometers at four Apollo landing sites recorded 28 shallow moonquakes between 1969 and 1977. Some of these shallow quakes could be associated with activity on the young faults. However, the epicentre locations of these quakes are poorly constrained. Here we present more-accurate estimates of the epicentre locations, based on an algorithm for sparse seismic networks. We found that the epicentres of eight near-surface quakes fall within 30 km of a fault scarp, the distance of the expected strong ground shaking. From an analysis of the timing of these eight events, we found that six occurred when the Moon was less than 15,000 km from the apogee distance. Analytical modelling of tidal forces that contribute to the current lunar stress state indicates that seven near-apogee events within 60 km of a fault scarp occur at or near the time of peak compressional stresses, when fault slip events are most likely. 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.

[1] https://www.nature.com/articles/s41561-019-0362-2

(To anyone who's wondered as well)

"Lunar seismicity was recorded by four seismometers placed at the Apollo 12, 14, 15 and 16 landing sites. These seismometers operated from 1969 to 1977 and recorded 28 shallow moonquakes."

and it's a more modern and definitely interesting approach to analyze these measurements. The conclusion which "strongly" suggests that "the Moon is tectonically active" is an argument to measure more in the future. The new measurements and the refinement of their analysis could surely increase our capabilities of modelling the rocks and the layers, even on the Earth. It doesn't however mean that the structure of the Moon fully matches that of Earth.

But also:

https://en.wikipedia.org/wiki/Geology_of_the_Moon

"Studies of the Moon's physical librations (small perturbations to its rotation) furthermore indicate that the core is still molten."

is a Wikipedia claim without the citation. But in NASA's article from 2011:

https://www.nasa.gov/topics/moonmars/features/lunar_core.htm...

"The team's findings suggest the moon possesses a solid, iron-rich inner core with a radius of nearly 150 miles and a fluid, primarily liquid-iron outer core with a radius of roughly 205 miles. Where it differs from Earth is a partially molten boundary layer around the core estimated to have a radius of nearly 300 miles."

Also note the estimated sizes of each layer:

https://www.nasa.gov/images/content/508668main_lunar_core_lg...

Also, the results of the GRAIL mission which ended in 2012 suggest that the lunar crust is thinner than the previous estimates.

https://www.teachastronomy.com/textbook/The-Earth-Moon-Syste...

"Even when there's no water to respond to tidal forces, the solid mass of a planet feels the stress caused by these forces. In fact, tidal forces can heat the interior of a satellite in an elliptical orbit. In that case, the satellite comes closer to the planet during one part of its orbit and there it's subjected to strong stretching forces. As it moves away from the planet the stress is partly released and the body relaxes back toward a more spherical shape. This continual flexing of the satellite creates heat through internal friction, in the same way, that if you flex a tennis ball enough times it becomes warm. This effect is called tidal heating. The more elliptical the orbit, the stronger the tidal heating. Jupiter's large Galilean satellites experience this kind of heating — enough to produce extensive volcanism on Io and possibly create liquid-water oceans beneath the surface of Europa."

The question is how the Moon could be more precisely modeled, and if some refinements to our models used on Earth too could be done, and for all that more measurements would be needed. The paper uses only those made from 1969 to 1977 from the seismometers placed by four Apollo missions, and tries to interpret the data with newer methods than what was done before with the existing measurements, but since 1977 there were no new measurements.

Also:

https://physicsworld.com/a/radioactive-decay-accounts-for-ha...

"About 50% of the heat given off by the Earth is generated by the radioactive decay of elements such as uranium and thorium, and their decay products. That is the conclusion of an international team of physicists that has used the KamLAND detector in Japan to measure the flux of antineutrinos emanating from deep within the Earth."