
The moon may be tectonically active - alanwong
https://www.nationalgeographic.com/science/2019/05/moon-may-be-tectonically-active-geologists-shaken-apollo-moonquakes/
======
ryannevius
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)

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xaduha
Didn'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.

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arethuza
The 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...](https://www.popsci.com/how-apollo-lunar-modules-were-smashed-for-
science)

~~~
wallace_f
Also, for the record this was explicitly discussed in the OP...

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vegasdew
Maybe it is ready to hatch.
[[https://tardis.fandom.com/wiki/Kill_the_Moon_(TV_story)](https://tardis.fandom.com/wiki/Kill_the_Moon_\(TV_story\))]

~~~
roter
My mind went immediately to Seveneves [0].

[0]
[https://en.wikipedia.org/wiki/Seveneves](https://en.wikipedia.org/wiki/Seveneves)

~~~
cblum
Such an amazing book. The first half at least.

~~~
elsonrodriguez
I thought the second half was great except for the part where it ended right
in the middle of everything.

~~~
cblum
I thought it went too crazy on the tech. The ring habitat was fine but the
spinning things that catapult them into space seemed a bit too far fetched.

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cuddlecake
As I understand it, the fact that the moon is tectonically active implies that
there still is enough heat in the moon's core to cause tectonic activity.

(To anyone who's wondered as well)

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simonh
The article talks about these movements occurring close to apogee (the point
in the Moon's orbit when it's furthest from the earth), so it looks like this
activity is driven by gravitational tidal forces rather than internal heat.

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tracer4201
I’m a bit out of my depth here, so someone more knowledgeable correct me if my
understanding is wrong.

In the article, they’re stating they believe it’s seismic activity because
it’s occurring within some distance of these fault scarps, which also appear
to be where the surface displays lines in the images shown in the article?

How are they dismissing it’s not a result of material from space striking the
surface? Is it that their sensors are able to disambiguate if the source is
from the surface vs deeper in the moon?

~~~
flukus
> How are they dismissing it’s not a result of material from space striking
> the surface?

The earthquakes are magnitude 5.5, plugging that into an energy calculator
([http://earthalabama.com/energy.html#/](http://earthalabama.com/energy.html#/))
gives a result of 0.2 Hiroshima bombs, which I think would be noticeable.

~~~
IanSanders
I wonder if the calculation requires correction due to moon/earth mass
difference.

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saagarjha
Moment magnitude is generally supposed to be correlated to the amount of
energy released, so I would tend to think that it wouldn’t need correction.

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pferde
Looks like Arthur C. Clarke guessed correctly in his sci-fi novel
[https://en.wikipedia.org/wiki/A_Fall_of_Moondust](https://en.wikipedia.org/wiki/A_Fall_of_Moondust),
where a moonquake causes problems to a "sand-cruiser" full of tourists.

~~~
marktangotango
Ha I remember reading that years ago, thanks for the reminder!

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xaedes
In south- and east-asia mythology a frog lives in the moon. This is part of an
australian aboriginal myth:

"The frog opened his sleepy eyes, _his big body quivered, his face relaxed,
and, at last, he burst into a laugh that sounded like rolling thunder_. The
water poured from his mouth in a flood. It filled the deepest rivers and
covered the land. Only the highest mountain peaks were visible, like islands
in the sea. Many men and animals were drowned. The pelican-who was a
blackfellow at this time -sailed from island to island in a great canoe and
rescued any blackfellow he saw" \- [http://www.sacred-
texts.com/aus/mla/mla09.htm](http://www.sacred-texts.com/aus/mla/mla09.htm)

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taneq
Pun intended.

~~~
Galaxity
I rolled my eyes, but then thought "ok, that's fair".

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bryanrasmussen
moon worms! joking aside reminds me very much of 50s sci-fi - maybe there will
be a mining operation to draw energy from the moon's core in the near future
(owned by Jeff Bezos)

~~~
atoav
Or we set out onto a the goal to tame the moonworms by the year 2119

~~~
bryanrasmussen
Moonworms are gentle, misunderstood creatures that have been horribly
exploited by mankind.

These majestic beasts are captured when young, and through a process involving
electric shock and sub-nuclear bombardment trained to perform tricks for the
amusement of lunar tourists who often like to ride on top of their backs and
put pictures of their abuse onto Facebook for exploitative likes.

Please donate 100 credits to Save the Moonworm - an offplanet non-profit
organized by the head of Jeff Bezos.

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taf2
I wonder if

“Without water, the lunar surface instead gets deformed, stretching from a
spherical shape into a more oblong one and back again.”

Is enough energy to keep the core of the moon hot? Like maybe the moons mass
alone for for 4+ billion years would have cooled but the additional force of
the earth stretching the moon like a rubber band creates heat energy...

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LeoPanthera
Shouldn't that be something like... "lunology"? Doesn't geo- refer to Earth?

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whateveracct
*shook

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dcbadacd
I would have loved if they had named the article "Moon shakes, geologists are
shaken".

~~~
conmarap
Still, the notion of shaken geologists because of earthquakes is pretty funny.

