November 7, 2011
I know that many of you are fascinated by volcanoes, and you will love today’s science news story. A city on the Atlantic cost of Spain has been completely evacuated, the port is closed to all ships and airplanes are banned from flying overhead, because of an underwater volcano that is threatening to erupt.
This is a submarine volcano ("sub" means under and "marine" means water). You might be surprised to know that 75% of the magma (the hot, liquid rock found inside a volcano) that wells up from beneath the earth’s surface each year comes from submarine volcanoes, but think about it. Volcanoes are spread all over our planet, and about 70% of Earth is covered by water. So, it makes sense that most magma flows happen underwater.
The volcano first started to emerge on October 9 off El Hierro Island, and researchers from the Spanish Institute of Oceanography (IEO, Ministry of Science and Innovation) used cutting-edge scanners to quickly map its formation. The image at the top shows the underwater valley as it appeared in 1998. The image on the bottom shows the new formation, with the volcano crater clearly visible and a "tongue" of lava flow running down into the valley. 
"It is spectacular to see how what was once an underwater valley is now a volcanic cone with its descending lava tongue," said Juan Acosta, head of the research team.
Photo: Canary Regional Goverment handout / EPA
Graphic: ScienceDaily.com
Posted by: Seymour Simon
