Tuesday, January 6, 2009


We often walk up the volcanoes and take friends up there. The most prominent is an island Rangitoto which is at the harbour.

Rangitoto was formed by a series of eruptions between 600 and 700 years ago. I have been there, and it is so young that the sea ward side of it is still barren volcanic rocks. The land facing side has scrubs.


The volcanic formations within the Auckland region have developed within the last 140 000 years. Volcanoes are a conspicuous feature of the Auckland city landscape. In some cases their form is emphasised by their preservation as reserves and parks, while in others they have been quarried to meet the city’s demand for building materials. Within a radius of about 20km centred on Auckland city there are 49 discrete volcanoes; this is the area referred to as the Auckland volcanic field.

The area covered by each volcanic centre is generally localised (less than a kilometre across) and the total volume of erupted material is small. However, five of the volcanoes (Mt Mangere, One Tree Hill, Three Kings, Mt Eden and Mt Wellington) are of medium size. The largest, Rangitoto, is an exceptionally large volcano for the field, representing 59% of the total volume of erupted material. It is significant that the five medium-sized eruptions occurred between 20,000 to 10,000 years ago and that the largest eruption was only about 600 years ago.

**8 This is a good pix of the Mt Eden Crater.***

1 comment:

Deb said...

Would you like to try making the link in your post a hyperlink?