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Fifty years on from the magnitude 7.1 Inangahua earthquake, scientists are reflecting on how much progress has been made since 1968.
According to GNS Science, the fallout from the second biggest land-based earthquake in New Zealand history would be unthinkable today. When the Inangahua happened there had not been a large damaging earthquake in New Zealand for 26 years and there was an element of complacency about natural hazards.
GNS Science said it took six hours before the epicentre of the quake was known with confidence, and its magnitude took even longer. The pre-dawn jolt at 5.24am on May 24, 1968 resulted in three deaths and 14 injuries. A further three people died when a rescue helicopter crashed. The quake left 70% of the houses in Inangahua uninhabitable.
“Today, that all happens within a few minutes of an earthquake and the information is made available publicly straight away,” the research institute said.
Former chief seismologist with GNS Science Warwick Smith, now retired, recalls that there were just two paper drum seismographs operating in New Zealand in 1968 – one in the Seismological Observatory in Wellington and the other at Canterbury Museum.
Geologist Simon Nathan, meanwhile said: “When the earthquake struck, I was astonished by its force. I had to hold on to the side of my bed to stop myself falling out.”
At the time, Nathan was a fresh graduate and one of the first scientists on the scene after the quake. GNS Science said he took charge of getting an extensive photographic record of the damage.
“There hadn’t been a big earthquake in New Zealand since 1942 and it was an exciting experience for a young geologist to witness such a massive upheaval of the landscape,” he noted.
The deadly quake has left Nathan cautious about buying a house that could be prone to earthquake damage. He said the quake initiated significant improvements in building standards, planning the siting of infrastructure, and to the way civil defences operate. These improvements have continued incrementally ever since.
GNS Science earthquake geology specialist and principal scientist Kelvin Berryman added that the earthquake had a major positive impact on geological studies and for understanding earthquake hazards in New Zealand.
Fast forward to 2018, the GeoNet project operates about 650 instruments in its nationwide monitoring network. About half are seismometers sending their data in real time to GeoNet headquarters continuously.
GeoNet, which started in 2001, is operated by GNS Science and is funded largely by the Earthquake Commission. Its nationwide network enables the quick location of earthquakes and the information is broadcast to all New Zealanders via the GeoNet website, app, and social media.
