Quick Dips

Going Up!

The Miramar Golf Club acquired an extra hole at the end of February -- about 80 metres deep.

It was drilled by staff and students of Victoria University's School of Earth Sciences and the Institute of Geological and Nuclear Sciences, who have been studying the Miramar Peninsula's geography for the last three years. They aim to find evidence of the effects of past earthquakes on the peninsula, which has been lifted by eight to nine metres over the past 7000 years.

In 1855 Wellington was devastated by a magnitude eight quake, over ten times more powerful than the 1987 Edgecumbe quake. The coast around the harbour was lifted up by about two metres by the earthquake, which was caused by movement along the Wairarapa Fault to the east.

Local Maori oral history, recorded early this century, describes what was probably the previous major earthquake to affect the Wellington area. By counting back through the generations of local Maori, it was estimated to have occurred in the 15th century.

This earthquake caused coastal uplift on Miramar Peninsula, and led to the final joining of Miramar to Kilbirnie across the Rongotai isthmus. Before this Miramar was an island, with a narrow seaway running just west of the present airport runway providing a second harbour entrance through which canoes travelled.

Evidence of old shorelines is preserved beneath the low-lying parts of Miramar, Strathmore and Rongotai, and in these areas the shorelines have been located by drilling into the sediments. The new drillhole will provide data on the older uplift history of Miramar, perhaps back to 100,000 years.

Researchers also hope to collect valuable information on the long-term climatic history of Wellington, using fossilised pollen grains trapped in the sediments. The plant pollen will show what vegetation was growing at various times in the past, and provide clues to the climate.