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Thursday, March 16, 2006

MOONQUAKES ?



NASA astronauts may need quake-proof houses as they are going back to the moon.
The moon is seismically active.Between 1969 and 1972, Apollo astronauts placed seismometers at their landing sites around the moon,instruments faithfully radioed data back to Earth.

And what did they reveal?

There are at least four different kinds of moonquakes:
(1) deep moonquakes about 700 km below the surface, probably caused by tides;
(2) vibrations from the impact of meteorites;
(3) thermal quakes caused by the expansion of the frigid crust when first illuminated by the morning sun after two weeks of deep-freeze lunar night; and
(4) shallow moonquakes only 20 or 30 kilometers below the surface.

The first three were generally mild and harmless.Between 1972 and 1977, the Apollo seismic network saw twenty-eight of them; a few "registered up to 5.5 on the Richter scale". A magnitude 5 quake on Earth is energetic enough to move heavy furniture and crack plaster. Shallow moonquakes lasted more than 10 minutes. The moon rang like a bell.

On Earth, vibrations from quakes usually die away in only half a minute. The reason has to do with chemical weathering: "Water weakens stone, expanding the structure of different minerals. When energy propagates across such a compressible structure, it acts like a foam sponge—it deadens the vibrations." Even the biggest earthquakes stop shaking in less than 2 minutes.

The moon, however, is dry, cool and mostly rigid, like a chunk of stone or iron. So moonquakes set it vibrating like a tuning fork. Even if a moonquake isn't intense , it just keeps going and going.

"Any habitat would have to be built of materials that are somewhat flexible," so no air-leaking cracks would develop. "We'd also need to know the fatigue threshold of building materials," that is, how much repeated bending and shaking they could withstand.

What causes the shallow moonquakes? And where do they occur? The Apollo seismometers were all in one relatively small region on the front side of the moon, so we can't pinpoint [the exact locations of these quakes].
We're especially ignorant of the lunar poles. That's important, because one candidate location for a lunar base is on a permanently sunlit region on the rim of Shackleton Crater at the Moon's south pole.

Proposals for deploying a network of 10 to 12 seismometers around the entire moon is on, to gather data for at least three to five years. This kind of work is necessary, to find the safest spots for permanent lunar bases.
Other planets must be shaking too.We have to study the moon before establishing habitats on mars or beyond.

NASA NEWS RELEASE

4 comments:

Gr81 said...

Nice info.
BTW, as u said there are different types of quakes occuring (depending on the depth of origin, kind of material b/w origin and surface etc.) So does that mean that a planet having various layers of materials will be having different kind of quakes with varying magnitudes, making it difficult for planning how 2 build labs etc. over there??
Buildings on Moon......
It seems difficult, but not impossible!

Varun Khetarpal said...

Wo ho ! Good question . See what happens is the seismic activity starts deep inside and depending upon the material the effect gets transported to outer layers.Since moon is rigid waves last there for a longer time and produce a tuning fork like effect as I have written.In order to built labs etc. we do have to take care about different complex aspects.

The Curly Brothers!! said...

this news is quite shaky!..
but let me tell you bout things that will shake you more...:
HERE:
Americans never ever went to the moon...the neil amstrong clip,photos,trassmissins were all carried out in area 51!!!..
there is a discovery sequel(which has been banned now)..which gave 20 proves that the images,the clips shown to the public were shot on earth!!...
for instance;
If u remeber the picture (Neil Amstrong on Moon with the American Flag Fluttering...remember??)..such a picture wont be possible coz there is no wind on the moon and hence no flag can flutter!!....
besides, astromnomically,at the time NASA claims that neil amstrong was on moon was during a solar something something which would have vapurised Neil!....he he!!
get the sequel..
its still on thr p2p's.

i had to post it here..as there is no msg box on your blog...get one.. nice bog

Varun Khetarpal said...

Hi Guys !

I know about this from ages and still get myself updated about the news related to the MOON HOAX.

I have something interesting for you.
Download this zip about the Moon Hoax
http://www.exploreuniverse.com/ic/Moonhoax.zip

Well, thanks for visiting !

This is science !

When you are speaking to technically illiterate people you must resort to the plausible falsehood instead of the difficult truth.

Photos of Comet Mcnaught !
Astro-photographer? Send your photos to pics@exploreuniverse.com and have them featured on this blog with your name. Comet Mcnaught : Pictures taken with Nikon D100 on 19/1/07 from Manning Point, northern NSW, Australia by Mr. Peter Enright.
Picture 1
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