Our biggest earthquake
Posted 23 January 2008 // Simon Nathan
Extent of shaking, 1855 earthquake
Today is the 153rd anniversary of New Zealand’s biggest recorded earthquake.
Shortly after 9 p.m. on 23 January 1855 a magnitude 8.2 earthquake shook central New Zealand. Although before the era of seismographs, it was clearly the largest earthquake to affect New Zealand in the last 200 years.
The earthquake was centred in south Wairarapa and caused a surface rupture for 140 kilometres along the Wairarapa Fault. A horizontal offset of 18.7 metres on an old stream channel was recorded – the largest known anywhere in the world during an earthquake.
The 1855 Wairarapa earthquake had a huge impact on the young city of Wellington, as there was widespread uplift of land. The track along the western side of the harbour had previously been impassable at high tide, but is now the site of the highway and railway line. The edge of the harbour at Lambton Quay was uplifted, and much of Wellington’s downtown area is now built on reclaimed land.
A tsunami accompanied the earthquake, with widespread damage around the southern coast of the North Island.
The only casualty in Wellington was Baron von Alzdorf, who was hit by a brick chimney falling from the hotel he owned. Two people died in a fissure in the Manawatū, and between two and six Māori were killed when their whare collapsed.
If such an event were to hit Wellington today, we would not get off so lightly.
