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The abstract from the actual study[1]: > The discovery of young thrust faults on the Moon is evidence of recent tectonic activity, but how recent is unknown. S
by ryannevius 7y ago
The abstract from the actual study[1]:
> 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 https://www.nature.com/articles/s41561-019-0362-2
- xaduha 7y agoDidn't people believe at some point that moon landings themselves caused the Moon to vibrate or something along those lines? Always found that eyebrow-raising.
- simonh 7y agoYou might be thinking of impactor probes, in which a vehicle is deliberately crashed into the moon (or another body) in order to generate shockwaves. Previously landed seismic instruments can us this to gather information about the moon's internal structure.
- arethuza 7y agoThe ascent stages of the Apollo Lunar Modules were deliberately crashed onto the Moon to generate shock waves to support seismology experiments: https://www.popsci.com/how-apollo-lunar-modules-were-smashed-for-science https://www.popsci.com/how-apollo-lunar-modules-were-smashed...
- wallace_f 7y agoAlso, for the record this was explicitly discussed in the OP...
- wuliwong 7y agoThere is a "hollow moon" conspiracy theory where one of the pieces of evidence cited is that the moon rang like a bell because of the impact of the lander.
- teh_infallible 7y agoI think what you meant to say is, “There’s evidence that the moon is hollow. It rang like a bell because of the impact of the lander.”
- cblock811 7y agoThey probably meant exactly what they wrote and didn't need a snarky correction.
- somatic 7y agoThe phrase “conspiracy theory” is a thought-terminating cliché used to delineate heretical from approved thought. If the Moon did indeed “ring like a bell”, it’s evidence of something, whether that something fits within our preconceptions or not. No, I’m not making an argument.
- astrobe_ 7y agoConspiracy theories (flat earth etc.) are twenty-teen trolling devices. Don't feed the trolls.
- acqq 7y agoThanks. It's based on the following data (from the same link): "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 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.html 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.jpg 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.
- politician 7y ago> Furthermore, shallow moonquakes lasted a remarkably long time. Once they got going, all continued more than 10 minutes. "The moon was ringing like a bell," Neal says. (2006) https://www.nasa.gov/exploration/home/15mar_moonquakes.html https://www.nasa.gov/exploration/home/15mar_moonquakes.html