A blue whale’s love song can reach 188 decibels, louder than a space shuttle launch at 170 decibels. But the loudest sound came from the 1883 volcanic eruption on the Indonesian island of Krakatoa, at an estimated 310 decibels. The pressure reading (how one can calculate sound) was the equivalent of 172 decibels, recorded 100 miles away on Jakarta. That shock wave travelled around the world three and a half times.