YOU THOUGHT YELLOWSTONE VULCANO WAS BIG? THE LARGEST IS MUCH LARGER AND IN A HIDDEN PLACE

 

Many people shudder at the thought of a mega volcano like Tambora or Yellowstone erupting.  They are considered to the most devastating eruptions on earth with a scale of coverage and plume range to make Etna and Mount St. Helen look like child's play.

To those who are nail biting through the reports of an imminent massive eruption at those sites, the recent discovery of a much larger mega-volcano should make for a bit of scary news. 

The largest volcano on earth actually lies beneath the Pacific Ocean, already a hotbed of volcanic activity.  It is called Tamu Massif and the 3-D map of the volcanic bed is depicted in the picture above.

In comparison, the largest volcano in the Solar System, Mons Olympus on Mars, is only 25% larger than Tamu Massif.  

The odd geology of the volcano has lead scientists to re-think classification.  In fact its slope is so mild you could barely tell there is a volcano.  

The volcano's area is 650 km wide, but only 4 km high.  The last eruption is believed to have taken place a few millions years ago.  It is believed to be extinct at this time. 

 

The caldera bed is similar to that of Mauna Loa volcano, mostly at the summit of the formation.  

For many years, the volcano was believed to be nothing more than an oceanic plateau.  Some scientists believe that the magma has escaped the earth's mantle through a 'punching' of the earth's crust.  Others instead believe that the tectonic plate boundaries might have fissures, or breaking points, where the lava can escape to the surface. 

This volcano opens a new chapter in the exploration and scientific explanation of how oceanic plateaus are formed.  An explanation must be found for the formation of the plateau in such a short time, i.e., how such a massive amount of magma was delivered to the top in a brief period of time. 

Geochemist David Peate believes that the Tamu Massif is in effect a very large shield volcano.  He feels that it is important to understand how such a large volume of magma, both as production and deposit and the time interval between those pulses, can generate a new working theory on the nature of such volcanoes. 

William Sager, lead geologist at the University of Houston, Texas, believes that there are many more volcanoes still undiscovered at the bottom of the sea.  

Sager also believes that in the case of the Tamu Massif, the bulk of the volcano itself sits below the earth's mantle, because it is so massive, the thin lithosphere, or crust, cannot support its weight, and for that reason it probably never emerged above the waterline.  

In contrast, large volcanoes like the Hawaiian volcanoes have emerged because they sit over portions of the crust that are very thick. 

Source : NBC news/ 9.6.13