TIL the 1883 eruption of Krakotoa which killed 36,417 people was so loud it was heard 4800KM away and the sound pressure wave travelled the earth over 3 times
The sound of the largest explosion is estimated to have been 180dB at 160km distance, and SPL falls off by 6 dB for each doubling of distance, so at the commonly used 1m distance it would have been over 280 dB.