Blocking Mt. Etna
I haven’t been following the story of the Indonesian mud volcano as closely as I should, but the new plan is to drop a bunch of concrete ball-and-chain units into the erupting crater. Those of us who have played with garden hoses as children are eagerly awaiting the upcoming footage of mud being squirted high into the air. However, the widespread skepticism prompted John Carpeneter to write to Nature with a wild story about a 1992 eruption of Mt. Etna:
The US Navy (in which I was then a commander), the Italian Navy and the US Marine Corps used exactly this approach successfully in Sicily, in Aprilâ€“May 1992, to slow and eventually redirect lava flow from Mount Etna that was threatening the small village of Zafferana.
We came up with this plan while talking to an Italian geologist. He spoke no English and I spoke no Italian, but I have a bachelor’s degree in geology and that helped a lot. We communicated on the back of a napkin while seated at a small restaurant at the ski lodge that became our base of operations. The navy units involved tried several different ways to place large decommissioned anti-terrorist barriers into a vent approximately 8,000 feet (2,440 metres) up the side of the volcano.
The first plan was to drop individual barriers into the vent, but that failed because of insufficient quantity, and the heat simply ignited the concrete. We then built a very large slide and were going to stack barriers on the slide and slip it into the vent. The slide was constructed but was impossible to move to the vent as mountain winds forced it into the path of the aircraft. (I filmed it on video and it is rather dramatic.)
Our third plan, which eventually worked, involved linking several dozen barriers together with asbestos-wrapped anchor chain and placing them in position around the vent. Additional concrete ‘Dempster Dumpster’ pads were placed directly over the vent on a net formed of anchor chain. When the entire assembly was in place it was blown into the vent using plastic explosive. US Navy and US Marine Corps CH-53E helicopters were used to place the barriers and transport the Italian explosives ordinance team required to place the explosives. The lava tube carrying lava down the mountain to the vicinity of Zafferana collapsed when flow was interrupted. That removed the immediate danger.
The long-term solution was to drive a bulldozer up the mountain, dig a very large canal and blow out the side of the vent. We had to change the engine on the bulldozer when we finally got it in place, as moving it up the hill destroyed the original engine.
Too good a story not to liberate it (er, well, most of it) from the Nature pay wall.