The Īnangahua earthquake
Posted 24 May 2008 // Simon Nathan
The 1968 Īnangahua earthquake
24 May is the 40th anniversary of the 1968 Īnangahua earthquake. With a magnitude of 7.1, it remains New Zealand’s largest on-land earthquake for more than fifty years.
Six people were killed in accidents related to the earthquake, including a helicopter crew repairing power lines. There was enormous damage in the surrounding hills, with huge landslides. State Highway 6, through the upper and lower Buller gorges, was closed for many months. Most large structures such as bridges survived with little damage because they had been designed to withstand large earthquakes.
I was asleep in the upper storey of an old wooden house in Westport. Just before 5.30 a.m. there was a huge earthquake, followed by an explosion above me. It turned out that the chimney had fallen over, and bounced down the corrugated iron roof. I can remember holding on to the bed, and wondering how long the shaking was going to last. It was much worse close to the epicentre, over 30 kilometres away.
40 years later there is little evidence of the earthquake. Most of the big landslides have naturally revegetated. But the people who lived through the earthquake will always remember.
There is a small museum at Īnangahua village, with many pictures of the earthquake, which is open most days.
The Inangahua earthquake remains the largest disaster EQC has had to deal with in terms of claims numbers - 10,500 - although it is well down the list as far as cost - $2.4 million - goes. The insurance scheme run by EQC is far different today. It covers just residential property, not all tangible property as it did in 1968, and the basis of settlement is replacement value, not the indemnity value of those days.
This means the same event occurring today would have a very different impact on EQC. Other factors like population change and repair costs would also affect this. EQC’s modelling shows that, if the same earthquake occurred today, there would be fewer claims - 4,500 to 5,000 - but the cost could be over $100 million.