Originally posted by magestyk7
reply to post by triplereiki
I think there is a connection with these quakes and the volcanos.
OK, let's just take a look at this one first. The bulk of earthquakes happen what we will call subduction zones - areas where the sea bed is plunging
down below the land. (I won't go into details as that is another can of worms so let's just take it as agreed)
The bulk of volcanoes happen around subduction zones, and yes there is a connection between the two. (I am not saying these specific quakes and
volcanoes but in general.)
The diagram below is off the US coast but the principle is the same.
[atsimg]http://files.abovetopsecret.com/images/member/5295d770978f.png[/atsimg]
You can see that where there is a subduction zone you get earthquakes and (not clear) volcanoes. This diagram may be a bit clearer.
Generally when an earthquake happens in one of these zones - and in particular when it is deep down - then if the magnitude is around the 6 mark
(sometimes a bit less) the ripples as Alysha said will spread out and will find their way all round the planet. This is what you see in the
seismograms. One single earthquake showing up all round the world and not simultaneous earthquakes in many places.
Right I'm trying to figure out what is making both happen. To me quakes are signaling volcanoes and the earth core's activity. Where is the
problem coming from that's making the Earth core kick out lava is what I'm trying to figure out.
Well I think I have covered that - it is the oceanic lithosphere (the sea bed) subducting under the land. If you drill down into the earth's core you
actually won't get all that far before the drill its begin to melt and the rock so mobile that you have to stop. The deepest hole in the world (in
Russia) got to 12 km before that happened.
Now bear in mind that this would be a shallow earthquake. They can be from 0 to 600+ km deep.
I'm keeping an eye out on many of the primary volcanoes that havent errupted yet. We all know many are due anytime soon and seems these seismic
events is warning us.
Seismic events do indeed warn us of impending eruptions, but a single one or two mag 6 events won't do it, depending on where they are. Generally
there will be a swarm of earthquake before an eruptive event. They may all be biggish one in the 5 to 6 range and may even have a 7 or two - but a
series of them does not necessarily mean a volcano is going to erupt. The was a bunch of quakes in the Moro Gulf recently, at least 4 of which were
7+, but no eruption. These were all very deep quakes.
Normally the precursors of an eruption will include harmonic tremor as well. Harmonic tremor is associated with the movement of magma, normally into
the magma chamber beneath the volcano as it gets ready to erupt.
Iceland and specially indonesia got me really interested. Monotering equipment is going crazy over there.
The volcanoes are getting worse too...
www.msnbc.msn.com...
Remember that at any given time there may be 20 or more volcanoes going off all over the world. There are 16 volcanoes that are continuously eruption
and these are found in Indonesia/Philippines, Kamchatka (Russia) and Central/South America. During the course of a year as many as 70 volcanoes may
have erupted and whilst these current events are both spectacular and sad at the same time because of the loss of life, they are not unusual. Even
Merapi is not actually behaving in an unexpected manner, although it seems to have caught the local team on the hop a bit.
So going back to the recorders 'ringing' as we call it, this actually is a common occurrence. There are 150 or so 6+ quakes every year. Any one of
those could ring the seismos, and often does. Remember the 6+ very deep quake in Brazil earlier this year? That made all the seismos black! Some of
the higher 5-5.9 quakes can also have the same effect. It is quite possible for these seismo events we have just seen to happen every other day for a
whole year.
Quake statsedit on 8/11/2010 by PuterMan because: to correct a
link