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Mountains dragged into chasm in seabed by tectonic action
A joint research by the British universities of Oxford and Durham, presented to the annual conference of the American Geophysical Union, revealed that the tectonic action is dragging giant volcanoes into a chasm in the Pacific seabed, destroying massive underwater mountains in the process. Sonar images were taken in waters up to six kilometers deep by a sonar in the Tonga Trench and used in the study.
Where the Pacific plate collides with the Indo-Australian plate, it is forced downwards into the trench, a subduction zone, and the volcanoes are carried with it. The Pacific Ring of Fire is vulnerable to tsunamis and has frequent earthquakes, thus one aim of the research is to understand whether the destruction of the volcanoes adds to the risk. One theory is that the volcanoes add friction to the movement of the two plates which leads to a greater build-up of tension and consequently to a more explosive quake. Another is that by shearing into blocks as they collapse, the volcanoes provide a kind of buffer easing the subduction process.
Publicado em: 8/12/2011 00:52:00
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