In the January 1944 issue of Popular Science, the piece titled “Can We Blast Japan From Below?” presents the argument. The author, Professor Harold O. Whitnall of Colgate University, said that “[the Japanese] have made gods of [volcanoes],” and “fear of volcanoes is thoroughly ingrained in the minds of the Japanese.”
He went on to say that fear of volcanoes is so great that the act of bombing them would cause “cataclysmic terror.” The point was to not only use psychological warfare, but to turn the volcanoes into weapons of war by inducing eruptions.
Whitnall said that after Pearl Harbor, an all out attack on the Japanese homeland should have been accompanied by bombing raids on Japan’s volcanoes to hasten surrender. Obviously, it never materialized. But was it possible? Theoretically, yes.
In short, if a volcano is near its time to erupt, a bomb can be enough force to set it off. The proposal reached President Roosevelt, but was never seriously considered. Perhaps it was a good thing, because had such measures been taken, the tragic events at Hiroshima and Nagasaki might not have been the only ones.