Need to Know
Tectonic Hazards are a type of Natural Hazard
- A natural hazard is a naturally occurring event that has the potential to affect people's lives or property. For example, earthquakes, volcanic eruptions and tsunamis.
- When natural hazards do affect people's lives or property they're called natural disasters.
- Earthquakes and volcanoes are tectonic hazards - they're caused by the movemnt of tectonic plates.
Cross Section of Earth
- Core - The core is located at the centre of the Earth and its the hottest part of the Earth. It consists of an Inner Core and an Outer Core. Both the inner and outer core are made out of iron and nickle. However the inner core is a solid ball and the outer core is liquid.
- Mantle- The mantle is the widest section of the Earth which surrounds the core. It is made out of a semi-molten rock called Magma which moves very slowly.
- Crust - The crust is the thin (about 20km) outer layer of the Earth. This crust is the solid rock layer upon which we live. The crust is devided into tectonic plates which are in constant motion.
Tectonic Plate Boundaries/Margins
Tectonic Plates are made of two types of crust - Continental and Oceanic.
- Continental crust is thicker and less dense.
- Oceanic crust is thinner and more dense.
The plates are moving due to convection currents taking place in the the rock in the mantle underneath them.
The places where plates meet are called boundaries or plate margins.
- North American Plate
- Eurasian Plate
- Pacific Plate
- Indo-Australian Plate
- South American Plate
- African Plate
Diagram of Plate Boundaries
Types of Tectonic Plate Margins
Destructive margins are where two plates are moving towards each other.
- Where an oceanic plate meets a continental plate, the oceanic plate will be forced down into the mantle and destroyed. This often creates volcanoes and ocean trenches (very deep sections of the ocean floor where the oceanic plate goes down).
A subduction zone is the area where an oceanic plate is being pushed under a continental plate.
- Where two continental plates meet, the plates smash together, but no crust is destroyed. -The area where continentak plates collide is called a collision zone.
Destructive Margin Diagram