LAVA channels created when Mount Etna blew its top in 2001 have prompted volcanologists to rethink the way volcanoes sculpt the Earth.
When a volcano erupts, lava flows etch channels in the mountainside several metres deep by melting the rock and simply washing it away 鈥� or so it was thought. But Jens Siewert and Carmelo Ferlito at the University of Catania, Italy, actually watched a channel forming during Etna鈥檚 2001 eruption, and they think the molten lava behaved more like a glacier, eroding the rock in its path.
Because the lava took only 12 hours to form a channel 220 metres long and 6 metres deep, it couldn鈥檛 have melted the rock 鈥� unless it conducted heat nearly a thousand times as efficiently as other lava flows (Physical Review Letters, vol 96, p 028501). 鈥淲e propose that the essential cause was abrasive wear,鈥� says Siewert. If confirmed, the theory could prove important for understanding similar channels on Mars and Venus.
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