Tokyo shrouded in midday darkness, trains derailed, roofs collapsing under volcanic ash: this is the vision Japan’s Cabinet Office laid before the public this week in a chilling simulation of a catastrophic eruption of Mount Fuji.The dramatic computer-generated film, unveiled on Tuesday to mark Volcano Disaster Prevention Day, is the first of its kind issued by the government. Officials say it is designed to sharpen public awareness of the risks posed by the 111 volcanoes that the...