Cordon Caulle - advanced of a rhyolitic obsidian flow a year after the eruption.

The behavior of a rhyolitic lava flow was analyzed by Dr. Tuffen, James Castro and Schipper in the volcanic field of Cordon Caulle in Chile.

This is the first direct observation of the progress of such a lava flow one year after the end of the eruption. Obsidian can be issued at the end of major explosive eruptions, as Vulcano, Yellowstone, or the Katmai ... but this was rarely observed . The most recent opportunities have arisen in the Puyehue -Cordon Caulle in 1921 , 1960 and 2011.

           Cordon Caulle - the plume from the eruption in 2011 - Photo Ivan Alvarado / Reuters

 
    The obsidian flows (1960 & 2011) of Cordon Caulle, seen by the satellite of the NASA EO- 1 Ali

Simplified map of the lava flows of Cordon Caulle with dates - doc . in Tuffen et al. / Ref. in Sources

         Cordon Caulle - obsidian flows of 2011-2012 - photo by Jonathan Castro, University of Mainz

The black obsidian , emitted by the eruption of 2011-2012 was spread on a light gray background of ash and volcanic debris.
In January 2013, the cast was still moving ... very thick , it moves just like a glacier.

Dr. Tuffen and the reports in his article in the journal Nature:
"We discovered that the lava still oozes a year later, and it advances of one to three meters per day. Though it moves slowly, it can accelerate or reduce its speed depending on the terrain " .

The team of scientists made ​​new discoveries about the progress of obsidian flows and modeling of advanced lava .
" The flow is like a solid rock cliff crumbling , high of more than 40 meters ... beneath the crust, the hot lava, over 900°C , flows slowly and can fear out on the edge of casting, helping the latter to move . "

          Cordon Caulle -  rhyolitic obsidian flows after a rain - Photo H.Tuffen / Flickr

 
Cordon Caulle - NE edge of the obsidian flow 04.01.2013 - three darkest extrusive lobes stand over 10 meters in length - picture in Tuffen et al. / Ref .. in sources

Cordon Caulle rhyolitic obsidian flow- lobes and points of extrusion - Advanced lava ratios  - doc . in Tuffen et al. / Ref. in sources

Satellite images reveal a lava field extended with localized extrusions , forming more than 80 lobes in margin of the thick flow . In January 2003, the front of the clava flow is 3600 meters from the vent, although a detectable feeding ceased for 6 to 8 months.
This illustrates the effect of thermal insulation of the outer shell of the casting , which promotes a prolonged horizontal transport and way of washing the extension of said casting .

This feature had been met until now only for the basaltic lava, red and fluid, but this rhyolite flow has obvious similarities !

Sources :

- Nature com - Exceptional mobility of an advancing rhyolitic obsidian flow at Cordon Caulle volcano in Chile : observations from Cordon Caulle, Chile, 2011-2013 / Tuffen Hugh & al. - link

- Global Volcanism Program - Puyehue-Cordón Caulle volcanic complex