The Loudest Sound in Recorded History
Scientists estimated the explosion's sound to be around 180 decibels, which is a great enough force to instantly kill all hearing tissue within a human ear. For comparison, 180dB is about 13x as loud as a jet engine from 100 ft, or as loud as a rifle shot at point blank range. People 2,200 miles away in Perth, Australia could clearly hear the eruption immediately after the explosion.
The pressure wave from the final explosion was recorded on barographs around the world, which continued to register it up to 5 days after the explosion. The recordings show that the shockwave from the final explosion reverberated around the globe 7 times in total.
Tsunami waves reached the coast of South Africa over 8,000 miles away, and smaller waves registered on tidal meters as far away as the English Channel. However, the English waves occurred too soon after the explosion to be remnants of the tsunami. Scientists believe these disturbances were instead a result of air displacement caused by the sound of the eruption.