CHAMPAIGN, Ill., March 25 (UPI) -- U.S. scientists say they have determined the cause of rotation found in volcanic plumes.
Using a 200-year-old report by a sea captain and a photograph of the 2008 eruption of Mount Chaiten in Chile helped University of Illinois researchers determined the spontaneous formation of a "volcanic mesocyclone" -- a cyclonically rotating columnar vortex -- causes the volcanic plume to rotate about its axis.
That rotation, in turn, triggers lightning and creates waterspouts or dust devils, the scientists said. The origins of the volcanic phenomena were previously unexplained.
"Rotation is an essential element of a strong volcanic plume," said Pinaki Chakraborty, a postdoctoral researcher and the paper's lead author. "By taking into account the rotation, we can better predict the effects of volcanic eruptions."
A photograph of the Mount Chaiten eruption showed what appeared to be a volcanic plume wrapped in a sheath of lightning. The 1811 sea captain's paper reported a volcanic vent that emerged from the sea in the Azores archipelago and formed a large volcanic plume.
The same process that creates a mesocyclone in a tornadic thunderstorm also creates a volcanic mesocyclone in a strong volcanic plume, Chakraborty said. "What happens in tornadic thunderstorms is analogous to what happens in strong volcanic plumes."
The research that included Professors Gustavo Gioia and Susan Kieffer is reported in the journal Nature.
