Water supply and agriculture were affected in the fallout from the eruption and the explosions of Hunga Tonga-Hunga Ha'apai could be heard as far away as New Zealand and Alaska.
It is now known to be the largest volcanic explosion ever recorded - double that of the next largest, Mount Pinatubo in the Philippines more than 30 years ago.
Professor of Volcanology at the University of Auckland, Shane Cronin has examined ash from the explosion, video footage and aerial images.
