Ok, can somebody explain to me why GREENLAND just had a 4.6

[kestrel91316]

earthquake?

http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008rpbr.php

I am thinking shifting masses of ice on top of the earth rather than traditional tectonic plate activity?

[janetblond]

1. Moving ice caps

NOT the sound of 1 hand clapping when they crash!

[arcos]

2. It has happened before...

http://www.newscientist.com/article.ns?id=dn8889

[phantom power]

3. hydrostatic rebound

I've heard people say this won't necessarily be so bad. That seems unintuitive to me. If Greenland loses a significant fraction of that ice mass, I don't see how it could avoid some significant seismic activity, as it floats higher on the mantle.

[Cleita]

4. Isn't Greenland partially volcanic?

That could explain it.

[GreenPartyVoter]

6. Most articles I found said no, but then I found this one: "Volcano Deep Down Could Be Melting

Greenland’s Ice"

According to them, the "hotspot" is located in the northeast corner of Greenland -- just below a site where an ice stream was recently discovered.

The researchers don't yet know how warm the hotspot is, but if it is warm enough to melt the ice above it even a little, it could enable the ice to slide more rapidly out to sea.

To measure actual temperatures beneath the ice, scientists will have to drill boreholes down to the base of the ice sheet-- a mile or more below the ice surface. The effort and expense make such measurements few and far between, especially in remote areas of northeast Greenland.

"The behaviour of the great ice sheets is an important barometer of global climate change," said Ralph von Frese, leader of the project and a professor of earth sciences at Ohio State University.

http://www.medindia.net/news/Volcano-Deep-Down-Could-Be-Melting-Greenlands-Ice-30702-1.htm

[Whoa_Nelly]

5. And there was just a 5.6 near Papua New Guinea

http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2008rpbx.php

Meanwhile, I keep watching the quakes in the Reno area (my former hometown of 20 years)

[gristy]

7. That is unusual. But I see no reason to link it to "shifting masses of ice"

Baffin Bay is the body of water west of Greenland and east of Baffin Island

[bananas]

8. Kestrel, if your cats start acting funny, let us know

All the talk of earthquakes lately is making me nervous.

[Cleita]

10. I've been dreaming of tidal waves lately?

Should I be nervous?

[kestrel91316]

12. My elderly female has been increasingly WEIRD in the last several weeks.

Stomping around and fussing more than normal (I know, it's really subjective, she's ALWAYS weird), and it's been unusually HOT (earthquake weather), and there have been an increasing number of moderately large quakes scattered all over the west.

We were commenting on it the other day. My assistant and both think something is coming. I just hope it hits far enough away to not ruin my business. It took us years to recover from the economic hit of Northridge.

[crikkett]

18. (deleted - I'm MOTO today)

MOTO - Master of the Obvious

[Warpy]

9. Quakes can happen anywhere

The theory about New England quakes for many years was that ancient buried volcanic plutons were still cooling and shrinking. Whether or not anybody is still promoting that theory is just a guess since I moved away 18 years ago.

Certainly the gain and loss of massive amounts of pressure as the ice sheet melts and shifts is a workable theory.

[kestrel91316]

13. "Ancient buried volcanic plutons"?? For shame, Warpy.

That sounds more than a little bit obscene, lol.

[Warpy]

17. Aw, get yer head out of the nether regions

of all those hypersexual tomcats you're relieving of their knackers!

Shame on you!

:evilgrin:

[Journeyman]

11. Because Greenland is on a planet with temblors? . . .

[kestrel91316]

14. Well, I look at the USGS earthquake site almost daily now,

and there is a distinct lack of earthquakes there in general.

I guess I'm just nervous. I think something's up. I just hope to hell it's not HERE.

[Dead_Parrot]

15. My money's still on Reno

Seems to dropped out of the news a little, but it's still grumbling away like a fat guy who missed breakfast.

http://earthquake.usgs.gov/eqcenter/recenteqsus/Maps/US2/38.40.-121.-119_eqs.php

[Dead_Parrot]

16. Another 4.6, just N of Canada

http://earthquake.usgs.gov/eqcenter/recenteqsww/Maps/10/260_80.php

Hmmm...

:shrug:

Edit to add Question:

If there was a series of explosive methane releases from melting clathrates on the polar continental shelf, what's the first thing you would know about it?

Sleep well...

[Javaman]

19. I had heard this very interesting yet very frightening theory about the

melting ice and the weight upon the earth. As the ice melts at the caps, the downward pressure that the ice has been exerting upon the land masses becomes less and less.

The theory goes on to say that the shape of the earth will actually change.

As a result, more earthquakes.

[itsrobert]

20. And the added weight in the ocean water will force water to

seep down into the earth thereby cooling the internal earth and starting the global cooling process. LOL

[bhikkhu]

21. That's the "hydrostatic rebound" mentioned upthread.

Or alternatively "isostatic rebound". I don't know if one term is more correct than another.

Greenland is a special case, with an ice sheet up two two miles thick. The effects of glacier loss elsewhere would be of a much smaller magnitude.