http://m.nautil.us/blog/the-sound-so-loud-that-it-circled-the-earth-four-times?utm_source=pocket&utm_medium=email&utm_campaign=pockethits


On 27 August 1883, the Earth let out a noise louder than any it has made since.

It was 10:02 AM local time when the sound emerged from the island of Krakatoa, which sits between Java and Sumatra in Indonesia. It was heard 1,300 miles away in the Andaman and Nicobar islands (“extraordinary sounds were heard, as of guns firing”); 2,000 miles away in New Guinea and Western Australia (“a series of loud reports, resembling those of artillery in a north-westerly direction”); and even 3,000 miles away in the Indian Ocean island of Rodrigues, near Mauritius* (“coming from the eastward, like the distant roar of heavy guns.”1) In all, it was heard by people in over 50 different geographical locations, together spanning an area covering a thirteenth of the globe.

A volcano on Krakatoa had just erupted with a force so great that it tore the island apart, emitting a plume of smoke that reached 17 miles into the atmosphere, according to a geologist who witnessed it1. You could use this observation to calculate that stuff spewed out of the volcano at over 1,600 miles per hour—or nearly half a mile per second. That’s more than twice the speed of sound.

In order to appreciate this... here is a video that would should give you a hint of what a volcanic explosion feels like