Volcano!

[beppe]

Originally Posted by GeoffC

Interesting that the link which lead to the section on Climate had no mention of the Laki incident which devastated Iceland and Western Europe in 1783/4.

[

Mother Earth gets rid of the flies on her back with a shudder of her thick skin. Like the old mare she is. When will some catastrophisicist propose human sacrifices again?

How many glaciations did we have in the last hump-th years?
How many times the orientation of the magnetic poles changed?
Where all the herrings of the Baltic sea go and with them the Anseatic League?
Why it was called Greenland? Just a promotion?
How thick the cenerite layer is in the Mediterranean Sea?
How tall are the Dolomites? All made with the bones of tiny living creatures.
I could go on and on.

You know (better than me) that a time correlation made on one point is ...
you choose the word.

Kisses.

[cmdahler]

Originally Posted by beppe

Why it was called Greenland? Just a promotion?

Actually, that's close to the truth. From Wikipedia:

The name Greenland comes from Scandinavian settlers. In the Icelandic sagas, it is said that Norwegian-born Erik the Red was exiled from Iceland for murder. He, along with his extended family and thralls, set out in ships to find the land that was rumoured to be to the northwest. After settling there, he named the land Grœnland ("Greenland") in the hope that the pleasant name would attract settlers. Greenland was also called Gruntland ("Ground-land") and Engronelant (or Engroneland) on early maps. Whether green is an erroneous transcription of grunt ("ground"), which refers to shallow bays, or vice versa, is not known. The southern portion of Greenland (not covered by glacier) is indeed green in the summer.

[GeoffC]

Originally Posted by kennyc

Yeah. I didn't realize the ash clouds caused lightning and the first time I saw it, though it was fake, but apparently is real.

Notoriously so ....

[DixieGal]

Geoff: That makes me wonder... has anyone ever died from volcanic lightning? Or is it a matter of if you are close enough to be struck by lightning, then you are probably already dead?

[GeoffC]

Originally Posted by DixieGal

Geoff: That makes me wonder... has anyone ever died from volcanic lightning? Or is it a matter of if you are close enough to be struck by lightning, then you are probably already dead?

Don't know is the honest answer ... I suspect that most of the lightning within the volcanic cloud doesn't actually reach the ground in the same way as thunderstorm lightning does.... It's likely generated by a different process....

[cmdahler]

Regardless of how the charge is developed within the cloud, the discharge as lightning can only happen because of an initial charge separation (positive and negative charges accumulate in separate areas). Near the bottom of an ash cloud, a buildup of polarization will induce an opposite polarization on the surface just below it. If the charge builds up enough potential, then lightning between cloud to ground will result. I don't know if anyone has ever been struck by ash cloud lightning - probably not, likely because such lightning itself would be an exceedingly rare event (if that kind of lightning killed you, then you could definitely say it was just your time to go...). Lightning between an ash cloud and the ground probably doesn't happen very much just because ash clouds don't tend to hang at low altitudes over the ground - they are violently thrown high into the atmosphere almost immediately, and by the time they drift back toward the earth, the particles are so dispersed that the charge potential isn't nearly enough to cause a spark, let alone lightning. I've seen pictures of ash cloud lightning before, however, in which a bolt or two was clearly striking the ground. Not a place I'd want to be standing.

Here's one link.

[kennyc]

Originally Posted by cmdahler

Regardless of how the charge is developed within the cloud, the discharge as lightning can only happen because of an initial charge separation (positive and negative charges accumulate in separate areas). Near the bottom of an ash cloud, a buildup of polarization will induce an opposite polarization on the surface just below it. If the charge builds up enough potential, then lightning between cloud to ground will result. I don't know if anyone has ever been struck by ash cloud lightning - probably not, likely because such lightning itself would be an exceedingly rare event (if that kind of lightning killed you, then you could definitely say it was just your time to go...). Lightning between an ash cloud and the ground probably doesn't happen very much just because ash clouds don't tend to hang at low altitudes over the ground - they are violently thrown high into the atmosphere almost immediately, and by the time they drift back toward the earth, the particles are so dispersed that the charge potential isn't nearly enough to cause a spark, let alone lightning. I've seen pictures of ash cloud lightning before, however, in which a bolt or two was clearly striking the ground. Not a place I'd want to be standing.

Here's one link.

Thanks for that!

[hidari]

Originally Posted by kennyc

Given the Iceland situation and the Major Impact on Air Travel, just imagine what a Supervolcano might do.

http://www.newscientist.com/article/...html?full=true


Course that's not as bad as The Great Dying a bit earlier:
http://en.wikipedia.org/wiki/Permian...tinction_event

IF I remember rite there are 5 super volcanoes... The Yellowstone one...errupted 600,000 years ago and is due for another. Hope I miss that one. I am more worried about he upteen dormant Volcanoes in my neigborhood...Japan...Not to mention the earthquakes.... C'est la vie...

SuperVolcanoes:

http://en.wikipedia.org/wiki/Supervolcano

Brought to you by the GOD: WIKI

[GeoffC]

... and the United States has two of them .... !

[kindlekitten]

Originally Posted by kennyc

Yeah. I didn't realize the ash clouds caused lightning and the first time I saw it, though it was fake, but apparently is real.

kind of makes you feel that those pictures may be representative of the early days (centuries) of land formation on earth...

[kennyc]

http://www.guardian.co.uk/world/2010...ion-human-race


"Iceland volcano: why we were lucky we weren't wiped out

The volcanic ash cloud from Eyjafjallajokull has caused travel chaos and misery. But we were lucky. An eruption in the future could wipe out the human race...."

[beppe]

Originally Posted by kennyc

http://www.guardian.co.uk/world/2010...ion-human-race


"Iceland volcano: why we were lucky we weren't wiped out

The volcanic ash cloud from Eyjafjallajokull has caused travel chaos and misery. But we were lucky. An eruption in the future could wipe out the human race...."

Let's hope that it keeps you (and your dear ones) and me (and my dear ones) out of it. By way of the mysterious powers to be.

P.S. Let's keep Geoff and Tom and may be Chicken and those they choose. I like dreams also. And others that I don't mention for privacy. The rest, out. vulcanized!