Earthquakes

Extreme Earth Events - 12ESS

Finn LeSueur

2021

Akoranga 17 Mahi Tuatahi

  1. Collect the volcanoes crossword
  2. Glue it into your book and complete!
  3. Put un-crumpled excess paper in the green bin

NB: 10 minutes max!

Te Whāinga Ako

  1. What type of plate boundaries and movements occur in NZ that contribute to earthquakes

Write the date and te whāinga ako in your book

Earthquakes

  • Recall: Earth is made up of tectonic plates which move past each other
  • Recall: New Zealand sits on the Ring of Fire
  • Recall: Most earthquakes occur on this ring of tectonic plates
Source

What Causes Earthquakes

  • Tectonic plates cannot move smoothly past each other due to high friction
  • Tectonic plates move suddenly
  • This sudden movement is a large release of energy
Source
Source
  • Energy moves through the ground as seismic waves
  • The point under the ground where the plates actually move is called the focus
  • The point on the surface, directly above the focus is called the epicenter

Pātai: What Causes Earthquakes?

There are two ways that earthquakes occur in New Zealand:

  1. Through volcanic activity (breaking of rocks through mantle pressure)
  2. Tectonic plate movement due to the movement of the mantle

It all comes back to the mantle!

Pātai: How to Plates Move?

Source
  1. Crust is being pulled apart. The land slumps downwards and away from the other block.
  2. The two blocks are driven together, one block climbs above another.
  3. Block move sideways past each other.

Sketch the diagrams & descriptions in your book.

Task/Ngohe

Put these steps in order in your book!

  • When the stress becomes too high, the block suddenly moves to a new position in just a few seconds.
  • Stress (elastic potential energy) builds up in the blocks of the rock.
  • Fault lines form both close and faraway from the stress to relives some of this pressure.
  • Blocks of rock on either side of a fault are stuck together, but tectonic plates (Pacific and Australian) are still moving slowly.
  • Energy is released in the form of seismic waves. We feel this as an earthquake.

Whakatika

  • Blocks of rock on either side of a fault are stuck together, but tectonic plates (Pacific and Australian) are still moving slowly.
  • Stress (elastic potential energy) builds up in the blocks of the rock.
  • Fault lines form both close and faraway from the stress to relives some of this pressure.
  • When the stress becomes too high, the block suddenly moves to a new position in just a few seconds.
  • Energy is released in the form of seismic waves. We feel this as an earthquake.

Ngohe/Task

Find and read the stuff article on Google Classroom on the Hikurangi subduction zone earthquakes.

Ngohe/Task: Types of Faults

  1. Find the Types of Faults activity on Google Classroom
  2. Complete the task