Onepoto Basin

Dr Phil Shane talks about his work studying rock cores from Onepoto Basin. This research helps the scientists learn more about the history of volcanic eruptions in New Zealand and perhaps predict when another eruption could occur.

Transcript

DR PHIL SHANE The research we have been doing here in Auckland is based on trying to get a record of the past frequency of volcanic eruptions. If we can get some idea of how frequent they have occurred in the past, and how big they are – like what we call the magnitude of the event – we might be able to get some idea of what could happen in the future.

So that led to our research at Onepoto Basin. We are interested in Onepoto Basin and other volcanic craters in Auckland because craters are places that often get filled in with sediment, they often become a freshwater lake. So anything that travels through the air like pollen, dust, but also volcanic ash will settle out in the lake, and we end up getting a nice continuous record of past events.

A lot of these craters are not very wide but they’re very deep – they can even be hundreds of metres deep – so if we want to extract a record from the past, we are going to have to drill into the ground. Sometimes we have to go down about 80 metres.

Although we call it drilling, it largely just involves pushing an open metal barrel into the ground 2 metres at a time and then extracting that sediment. And then we piece it all together back in the lab, and we end up with records of sometimes 80 metres long and can represent 100,000 years or more.

Acknowledgement: Dr Paul Augustinus, University of Auckland