Krakatoa in the 18th century, but all historical reports does not match with this one. An explosion of this size would spit chunks of lava in the air which would cool very quickly forming stones, in the Krakatoa event it was noted by people sailing in the area that those stones fell right in the deck's ship and on shore. There were reports saying something about vaporized ashes, very thin ashes in this recent event in Tonga.Posted by Carlitos (here)
I have searched the web, and have not found, nor ever seen a volcano explode so violently, in one single event. does lead one to think..
I am no expert on these things, but it is very strange indeed, I doubt anything else than what we saw already will come out of this, in a few months nobody will be talking about.