The Kaikoura Earthquake Monday 14 November 2016 12.04 am Engaging with Science The Kaikoura Earthquake Monday 14 November 2016 12.04 am

We live on a DYNAMIC EARTH This means one that is constantly changing. Sometimes changes to our earth are slow so happen over a very long period of time eg erosion by rivers carving out valleys. Other times our earth changes very rapidly such as when sudden and powerful earthquakes happen such as in November 2016 in an area around Culverden in the South Island. Lets remember what we know about the geology of NZ

Plate Tectonics The earth is made of large plates called tectonic plates New Zealand lies on the boundary of 2 plates called the Pacific plate and the Indo- Australian plate and the Alpine Fault (a long break in the rocks) marks this boundary. The earth is made of large plates called tectonic plates New Zealand lies on the boundary of 2 plates called the Pacific plate and the Indo- Australian plate. The Alpine Fault (a long break in the earth’s crust) marks this boundary in the South Island

Plate movement These plates move because they dragged by the moving mantle beneath. The mantle is moving due to convection currents

Crustal movement Movement along the edges of plates can be: towards each other (colliding) called converging boundaries sideways movement (moving past each other) called transform boundaries away from each other called divergent boundaries.

The Indo Australian plate is moving North-east and the Pacific plate which is moving West. How are we moving?

In the North Island The Pacific plate is diving under the Australian plate. This causes lots of deep earthquakes and volcanoes. For example White Island, Ruapehu, lots of dormant volcanoes in Auckland and the dormant volcano of Lake Taupo.

In the South Island Down very deep the Pacific plate is going underneath the Australian plate. However closer to the surface, crust on the Pacific plate is colliding and sliding. The collision pushes up the Southern Alps as much as 10 mm a year. The earthquakes here are shallower.

While the Alpine fault runs in a north-south direction, the Greendale fault that we studied ran east-west.

At the north eastern end of the South Island, there is a complex system of faults that radiate out in the North east direction from the Alpine fault. 6 faults are known to have ruptured during the 7.8 magnitude earthquake on 14 November. 4 went along the coast and out into the sea.

Earthquake progression The quake started weakly in Waiau and then slowly built up.The real burst of energy that contributed most to the size of the quake was between Kaikoura and Cape Campbell. It raced towards Cape Campbell and then stopped in it’s tracks because the Cook Strait faults acted as a barrier. Click on the link below to watch a computer simulation of the 7.8 Earthquake https://www.youtube.com/watch?v=z1HWet9j070&feature=youtu.be

Effects It was the sudden slowing down which caused the uplift of the coast by ~ 1m and shunted that part of the South Island 2 m closer to Wellington. It’s a bit like a car braking sharply to a stop and the passengers being thrown suddenly up and forward.

The quake started in Culverden where an existing fault broke which triggered the breaking of 3 more faults, one after the other and this pattern extended up the coastline north towards Kekerengu where it went offshore.. It is believed that onshore the faults extended for 130 km. It is believed that land in some places especially along the coastline has been uplifted by 1-2 metres in places, thereby raising the sea bed and sealife on the rocks eg seaweed, paua and crayfish. Some reports say a rise of 6m occurred(vertical displacement). The land is reported to have moved horizontally 2-3 m to the North east.

Fault Pattern In upper South Island

Exposed coastline after the earthquake

Kaikoura coastline before and after the 14 November earthquake

A fault is a break/fracture in the earth’s crust caused by an earthquake. Sideways movement along a faultline is called a strike slip fault. This is the type of movement that occurs along the Alpine fault. The Greendale Fault is a strike slip fault and in a few places there was reverse faulting.

14 November earthquake movements Strike slip and a reverse faulting occurred in the the 14 November quake.

Road damage

Road and railway track damage

A photo taken and received on November 14, 2016, shows a freight train partially buried by landslide near Kaikoura on the South Island's east coast.

Road tunnel damage

Massive canyon formed during the earthquake http://www.stuff.co.nz/national/nz-earthquake/87041485/christchurch-mans-drone-footage-captures-extent-of-massive-quake-canyon

Click on the link below to listen to Dr Kelvin Berryman describe the effects of the earthquake https://www.youtube.com/watch?v=EDnjsVH2jxU

Click on the link below to watch a flyover after the 7.8 earthquake https://www.youtube.com/watch?v=jxYLOXoZ728

TASK Using your knowledge of earthquakes and the Kaikoura earthquake, make up a poem or a song to show your understanding and which gives a message to others about NZ earthquakes.