New Zealand's South & North Islands moving closer, one city sinking after 2016 earthquake

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The devastating New Zealand earthquake in November 2016, measuring 7.8 on the Richter scale, have had long-lasting effect on the islands of the country.

The two main islands – North Canterbury and Marlborough landscape – are “creeping” closer to each other with each passing day while Nelson city at the top of the South Island is sinking.

The Kaikoura earthquake, that struck just after midnight, raced north from the middle of the South Island towards Cook Strait covering 170 kilometres in about 74 seconds, tearing apart 25 fault lines. The quake claimed two lives and left several injured. 

“But the changes unleashed have not finished yet, with post-quake monitoring showing Cook Strait is getting narrower as the northern part of the South Island edges northeast,” reported media news outlet Stuff.

According to GNS Science geodetic scientist Dr Sigrún Hreinsdóttir, the Cape Campbell is now about 35 centimetres closer to Wellington, while Kaikōura town slid about 15cm east, Blenheim 15cm northeast towards Cook Strait, and Nelson had slipped about 5cm southeast. “Sites in the Marlborough Sounds had moved northeast by about 10cm, but land around the Waiau epicentre had barely moved. Wellington had also shifted about 5cm northeast since the quake,” she said.

Scientists are now calling it one of the most complex earthquakes observed anywhere in the world.

"In reality we are having all this creeping going on and the question is, which (fault) is the dominant factor?

"The whole area is going down maybe 10 to 20 millimetres. It's not a huge amount but it is observable at our sites," said Hreinsdóttir.

New Zealand lies in the collision zone between the Indo-Australian and Pacific tectonic plates, part of the Pacific Basin Ring of Fire, and experiences more than 15,000 earthquakes a year although only 100-150 are strong enough to be felt, writes news agency AFP.