Nikita McDonald, of Aranui Primary School, asks :-

How many volcanos are there and which is the biggest?

Alexa Cameron, a geologist at the University of Canterbury, responded.

You don't say if you are looking at volcanoes just in New Zealand or the whole World, so I'll give you the information for both.

In New Zealand there are 10 active volcanoes on land, with other submarine active volcanoes offshore. Active volcanoes can erupt at any time, producing lava, ash , steam or gas.

The largest volcano in New Zealand is Mt Ruapehu and, as you know, that has certainly been active within the last few years, showering ash over a wide area of the North Island and ruining the ski seasons.

New Zealand has only a few active volcanoes though compared to the 1511 active volcanoes listed all over the World.

The highest volcano in the world which has erupted in historic times is Llullaillaco. It is 6739m high and is found in the North Chilean Andes mountains. The largest volcano is Mauna Loa in Hawaii. It looks like a small island way out in the ocean, but it has formed right from the sea bottom, so it is very high indeed.