During the summer of 1999 I decided to learn more about WHAT volcanoes
are, and what made them xxxx from time to time.. And I did not get far
before I met the xxxx 'plate-tectonics'.
What's that again?'. Well, that was the definite fact that our Earth
consisted of quite a few plates, upon which the continents were floating
around, again upon something else further down in the deep.
Sounds interesting? At least it did to me. And so I
began searching. Mostly on Internet, but also in my own books and encyclopedias.
The result was quite confusing.. See my page: Platetektonikk???.
(PS - it's a large one, and still only in norwegian - sorry!)) The situation
did not become easier when I got in touch with a 'rebell' on this theme,
a professor at the university i Bergen, Norway, and received some of
his thoughts about plate-tectonics.That's why I have included questionmarks
after the title 'Platetetektonikk'. But what then have I learned? Actually
I had to learn something while studying?
Well, to be honest, I first of all learned that I did
not know much at all about this thing called volcanoes and plate-tectonics.
But to get further in this story, one has to know a little more about
the theory called plate-Tectonics and its history, but have to put
that on another page, so this piece here won't be too long......
click on map for larger version
As shown on the map above, the earth is cut into several pieces, all
borders consisting of either a crust or a subductionzone or what else
it might show up to be. OK, so we are almost sure that those pieces
are plates, and that some of them moves in certain directions,
at the time being, about 2-12 centimeters ( 2-3 inches?) each year
We are also sure that some of them goes down under the others, in socalled
while others are colliding, like in a car to car crash, and they form
large mountain-chains etc. Other plates moves along each other, some
in opposite directions, which makes crustzones, and here we can find
the larges earthquakes (California, Indonesia and recently Turky 1999),
and also some of the most active volcanoes (California, Turkey???).
Indonesia is the country with most volcanoes compared to its size.
But then - here comes the questions. You ought to have a subductionzone
to keep kind of balance of the earth - the radiant, or the distance
from the center of the Earth and to surface at the equator line or to
one of the two poles, has to be constant. (xxxx km at the poles). From
the spreading-zones comes up new lava, and new landmasses forms, and
the plates move away from here. Subduction zones are typically deep
trenches, where one of the plates dissapers downwards (usually the ocean-plate).
Deep sea trenches are found off the coasts of the Philippines, Japan,
Indonesia and Alaska. But where are the deep trenches supposed to take
care of all the other plates? Look at the map below, and click to view
a larger map.
Plateboundaries (+|+|+) and trenches (violet)
click for large scale
The plates are floating in certain directions, away from the spreading
zones and supposed to finally
reach a subduction zone, or to collide with some other plate. That is
why chains of islands, and chains of volcanoes that have popped up on
top of so called hot-spots in the earths surface, is lying just like
that, in chains similar to the direction of the actual plate they are
a part of, with the oldest top nearest to the place where the plate
is going to end up.
But somehow there are a lot of other trenches in the
big oceans where nothing is happening. Nothing dissapears, and nothing
comes up. At he same time there are mountain ridges coming up both here
and there the more maps you can get hold of. How or what have made them
It's still a bit too difficult to understand these theories,
so I'm going to continue my study.....
Put your opinions right down in
Since then I have listed more than 200 different volcanoes, each has
its own page
here on my site. And you bet I've learned a lot. But I am still learning.
Read more about that here.
from my surfing for Volcanoes
October: I am still learning....