Natural Hazards & Tectonic Hazards

• What is a natural hazard?

  A natural event when the hazard effects people and human activities
• Oceanic crust (plate)

  1. Found beneath our oceans
  2. Between 5km and 10km thick
  3. Heavy, dense, younger
• Continental crust (plate)

  1. Found beneath our land
  2. Between 25km and 100km thick
  3. Lighter, less dense, older
• How do plates move?

  The core is the hottest part of the Earth. Heat is radiated out towards the surface (crust), with heat energy spreading through the mantle, where it creates molten magma. The hot magma moved around in the mantle due to a process called convection. Heated magma rises towards the crust where it begins to cool, becomes more dense and sinks again. Once it reaches the core, it is reheated and the process continues. These convection currents are responsible for forcing the floating tectonic plates to move.
• What is an explanation of a destructive plate boundary?

  The continental and oceanic plates meet, the oceanic plate is denser than the continental so it is subducted beneath the continental plate. Friction between the plates causes earthquakes. As the oceanic plate moves downward and melts. This creates magma. The magma breaks through the surface to form steep-sided composite volcanoes. When 2 continental plates meet, there is no subduction. Instead the crust becomes crumpled and uplifted. This is a collision boundary.
• What is an explanation for a constructive plate boundary?

  The plates move apart causing earthquakes. Magma forces its way to the surface. Reaching the surface, it forms volcanoes, because the magma coming from the Earth's surface cools when it reaches the crust. The volcanoes tend to be very flat 'shield volcanoes' as the magma is very runny and flows a long way before cooling.
• What is an explanation for a conservative plate boundary?

  At conservative margins, the 2 plates are moving past each other. Earthquakes happen at long conservative margins as stresses build up gradually over many years. There is a lot of friction between the plates. Earthquakes are suddenly released when the plates slip and shift. They can be destructive as they are close to the Earth's surface. There are no volcanoes because there is no magma.
• What is the defintion of monitoring?

  Using scientific equipment to detect warning signs of events such as a volcanic eruption.
• What is the definition of prediction?

  Using historical evidence and monitroing, scientists can make predictions about when and where a tectonic hazard could happen.
• What is the definition of protection?

  Designing buildings that will withstand tectonic hazards.
• What is the definition of planning?

  Identifiying and avoiding places most at risk, prepare evacuation plans, do earthquakes drills and fund emergency services.