Sociable

Saturday, May 21, 2011

End of the World, 158 Mile Deep Earthquake, Iceland Volcano



Humorously put: Right now I'm too busy blogging this and being a rock nerd to even pop my cork for some bubbly, bringing in the end of the world...


Just now we have two very interesting things going on as far as earth movements go, and right at a time, an hour ago (3 pm PST) when the world was supposed to end. Of course I'm mentioning the end of the world humorously, for who really knows if, how and when that will happen. But indeed, at 3 pm PST, there were crowds at Times Square, and an interesting deep quake and a volcanic eruption happened then.


We have had a 5.0 mag earthquake at the depth of 158 miles down. This is a complex and very deep subduction zone in the Banda Sea, north of Darwin, Australia. This is an are capable of very large earthquake because of a subduction zone, and where the plate is very deep and melting off some material, it kicks off some powerful and dangerous volcanos. These volcanos associated with the subduction zones in the area are usually of the explosive andesitic type, much like the famed and deadly Krakatau.


A subduction zone is an area where one plate, usually oceanic, crashes into another tectonic plate, and normally, because it's a thinner plate, it will bend downwards, and slide under the lighter thicker plate it has crashed into. The sinking plate dives into the semi-molton mantle below, and melts off some of the salt water bearing rock. That rock can turn into granite and andesite as it moves up through the mantle, and the crust.


In the picture here, with the colorful bands of dots, we can actually see the depths of the earthquakes in the past, those associated with this subduction zone.


You can see the more shallow quakes, where the orange dots are, which are 35 km deep to the surface. These tend to be the west most earthquakes. This is an area where the plate is not as deep.


The yellow dots are where the quakes a bit deeper, 70 to 35 miles down, and represent where the plate is deeper and grinding against the other plate and material there.


The green dots represents a depth of 150 to 70 km, and blue 300 to 150 km down. This is where the sinking plate is well into the hot mantle material below, causing a partial melt of both plate rock and mantle material.


We also see purple dots, representing earthquakes at 500 to 200 km down, and then a few red quake dots, those being 800 to 500 km down.


Look closely at the map, and look for chain islands and indicators of volcanism. I like to Google Earth this area too, to see the fantastic volcano chains in detail.


Krakatau is a volcano set between Sumatra and Java, and it is believed to be an area where sinking tectonic plates are twisted.


Here's a link on today's deep earthquake:


http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0003kwv.php#details


Also, in south eastern Iceland, a very active volcano started erupting just at the supposed end of the world was due to happen. It is in an uninhabited part of Iceland, and a large plume already has been seen and photographed. It just blew about an hour ago as of this writing, 4 pm PST. It probably won't do much more than send ash into the air, and probably won't cause extensive air traffic problems, judging by the past behavior of the volcano. This volcano erupted in 2004. Right now there are earthquakes associated with that volcano too. Here's a link to the first news reports on that event:


http://www.abc.net.au/news/stories/2011/05/22/3223393.htm?section=world

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