Thread: Earthquakes in Space

If we get earthquakes here, do other planets do? Do we have enough evidence to suggest that? Or are we still looking for answers?

Originally Posted by LHoneyman9913

If we get earthquakes here, do other planets do? Do we have enough evidence to suggest that? Or are we still looking for answers?

I think it is the latter. The attached Wiki article has a bit about plate tectonics on other celestial bodies: Plate tectonics - Wikipedia, the free encyclopedia

I was interested to see one hypothesis is that water may play a key role in weakening the surface to allow shear zones to develop. If this is right then extraterrestrial plate tectonics may be fairly rare in the universe. I'd like John Galt's opinion on this however.

Is volcanism evidence of plate techtonics? We can identify volcanism fairly easily. Active volcanism has been seen on the moons of the gas giants. Evidence of past volcanism on Mars is Olympus Mons. Active volcanism seems to be linked to tidal forces.

Originally Posted by Sealeaf

Is volcanism evidence of plate techtonics? We can identify volcanism fairly easily. Active volcanism has been seen on the moons of the gas giants. Evidence of past volcanism on Mars is Olympus Mons. Active volcanism seems to be linked to tidal forces.

I'm no expert but I don't think plate tectonics is needed for vulcanism - all you need is fluid or semifluid rock beneath the surface which rises to find an exit. It seems to me this does not necessarily imply the kind of convection cell circulation of solid (albeit slightly plastic) rock that we have on Earth. But I could be wrong.

Volcanism can be caused by the powerful gravitational pulls of larger bodies as well. The constant flexing of the crust of the satellite causes volcanic activity. Any planet with active tectonics will obviously have earthquakes.

didn't some of the Apollo crews leave behind equipment that measured moon quakes ?

When I read the title of this thread I had a wonderful visual of a space opera "space ship" being shaken in deep space by a "space quake". "What's happening Captain Buck?, asks the pneumaticly proportioned blonde space cadet in the unlikely short skirt. -- steely eyed Capt Buck replies, " Don't worry Wilma, its just a space quake."

A quick, back of the envelope, summary. (Keeping in mind that earthquakes can only occur on Earth. Elsewhere they are seismic events.)

Firstly, anywhere we have vulcanicity we have associated tremors. For example, the shape of the Yellowstone magma chamber has been defined through analysis of the hundreds of small events that occur weekly as a consequence of magma movement. There are volcanoes on all the terrestrial planets, Io, Titan and Enceladus, and there must be tremors associated with these.

Secondly, impacts by bolides will generate seismic events and all solar system bodies are struck by these. In the past these have been capable of generating events that would far outstrip in magnitude an internally generated one. The impact that produced the Caloris basin on Mercury, the mare forming lunar impact, the Agyre basin on Mars, and others spring to mind.

Thirdly, tidal stresses induced in a planet or satellite may produce adjustments, i.e 'earthquakes'. Many of the satellites of Jupiter and Saturn would likely experience such instances.

Mercury:
I would not anticipate anything significant here, other than minor flexuring from tidal effects. I can find nothing in a very quick scan of my library.

Venus:
Currently, setting aside vulcanicity and impact, there is probably no meaningful seismic activity.

Mars:
There are features here consistent with substantial movement, but nothing that appears recent.

Io:
Probably as crazy as hell. This is a happening place.

Ganymede:
Definitely had major surface movements in the past. Currently dead?