A hiker traipsing around Hawaii's Mauna Loa volcano came across a strange find last month: two rusty, decades-old bombs, both unexploded. But as Live Science reports, the find by Kawika Singson has a logical explanation, one that goes back to the 1930s. Back then, a prominent Hawaiian volcanologist pushed the idea to bomb the volcano after an eruption sent lava flowing toward the city of Hilo. His thinking was that the bombs could create new channels for the lava and save the city's water supply. The US Army Air Corps agreed to the experiment. "Our purpose was not to stop the lava flow, but to start it all over again at the source so that it will take a new course," said the man behind the idea, Thomas Jaggar, in a 1935 radio broadcast, per a post at the US Geological Survey. Did it work? Not so much, though Jaggar claimed success at the time.
He argued that the bombs hit lava tunnels, which exposed them to air and caused them to cool. This hadn't been the original intent of the mission, but the bottom line, he argued, is that the bombing helped save the city of Hilo. Subsequent investigations have cast doubt, however. The lava did indeed slow after the bombs fell, but "the cessation of the 1935 flow soon after the bombing must be considered a coincidence," concluded a field investigation in the 1970s. The current USGS post says this: "Our view is that the bombing was carried out as the eruption was already waning." The post adds that bombing volcanoes is probably not an option for most eruptions, but it could be considered on a case-by-case basis. In the meantime, authorities are working on a plan to remove the unexploded bombs, which are in a remote location, per West Hawaii Today. (Read more Mauna Loa stories.)