Researchers from Britain have unveiled the most detailed survey of the South Pacific -the most seismically active area of the planet.
They utilized sonar to create pictures of the seabed, and observed the process of demolition of the undersea volcanoes in the Tonga Trench.
The researchers are trying to understand the causes of the tsunamis that afflict the area.
They made pictures by sonar in waters up to 6km deep.
The volcanoes are strung across the ocean bottom and are moving westward on the Pacific tectonic plate.
The trench forms the second deepest stretch of seabed in the world.
It reaches a depth of 10.9km.
The trench is a very active fault line going north from New Zealand in the direction of Tonga and Samoa.
The discoveries are the result of a joint project by the Oxford and Durham colleges, financed by the Natural Environment Research Council.
[mappress] Subsea World News Staff , December 07, 2011; Image: WHOI