Extreme Earth Events - 12ESS
The Earth is composed of 4 main layers - the inner core, outer core, mantle and crust. The outer core is a liquid and extremely hot. The mantle above it is made of semi solid rock. The intense heat from the outer core causes the bottom layer of the mantle to become less dense, and because of this it rises. As the rock gets closer to the crust it cools down and becomes more dense, and begins to sink. This process repeats, resulting in a continuous movement called convection currents. These currents are responsible for the movement of the tectonic plates of the crust above.
Write the date and ngā whāinga ako in your book
Mass per unit of volume - so how much stuff is packed into a given space.
The area where two tectonic plates meet is called a plate boundary. Mountains, volcanoes and oceanic trenches are formed at plate boundaries, and earthquakes are more likely to occur here.
Sketch these boundaries into your book.
The plates move away from each other.
The plates often get stuck as they try to move past each other due to friction. Over time this builds up great pressure until finally they jolt past each other. The sudden movement causes an earthquake which may be violent and cause great damage.
When two plates move together and collide. Comes in three types.
The denser oceanic crust subducts under the continental crust, typically making a mountain range/island.
The denser of the oceanic plates subducts under the other. Sometimes creating magma plumes and creating an island arc system (e.g. Japan), as well as an oceanic trench.
The denser of the continental plates subducts under the other, creating a mountain range.
Open Google Classroom to find the Density Investigation