I've just been reading a book I aquired recently called "Living on the Edge" and I noticed that it is available online for free. The website is a NZ govt one and 'Te Ara' is a multi-media encyclopedia about NZ, It can be a short or long read online, depending how much time you have, but is interesting in it's descriptions of volcanoes earthquakes and other potential disasters. Go to https://teara.govt.nz/en/volcanoes
Maybe look at the Taupo section first.

Very interesting but talking of what went on a million years ago, how could anyone possible find details that long ago. Hope all is well for you. Big hug for Rosie. Take care, cheers.