Sudden movement between the two plates sometimes causes earthquakes. In this area the center of the earthquakes is usually very deep so violent quakes are not typical. Above the edge of the diving Pacific Plate - about 75km underground by this stage - there are a line of volcanoes. They run in a north easterly direction from Ruapehu to Taupo, Rotorua, and onwards through White Island.

During an eruption, as the Magma rises, gas is released in a similar way to opening a soft drink bottle. The amount of gas varies according to the makeup of the magma and is one of the things that give a more energetic eruption. On your visit to Lake Taupo, try throwing one of the beach rocks into the water - they float! The pumice rocks from Lake Taupo are very porous, suggesting an extremely violent eruptions. There are a few other clues to the violence of Lake Taupo's eruptions, like the size of the hole it has left behind - the lake is the same size as Singapore!

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