The Challenge Of Natural Hazards Part 1 Flashcards
What is the definition of a natural hazard
Are extreme natural events that can cause loss of life, extreme damage to property or disrupt human activities
What are the 5 types of hazards
Geological
Hydrological
Climatological
Meteorological
Biological
What is a geological hazard
When the earth crust moves
What is a climatic hazard
Changes in earths climate
What are the four factors that affect hazard risk
Urbanisation, poverty, climate change, farming
What is the layers of earth from outside to inside
Crust
Mantle
Outer core
Inner core
What are the two types of crust
Oceanic and continental
What is ridge push
When the weight of an elevated ridge pushes an oceanic plate towards the subduction zone
What is slab pull
When older denser tectonic plates sink into the mantle, pulling newer and less dense sections of plate along behind
What are convection currents
A movement within the earths mantle caused by the heat of the core
Where is oceanic crust found
Underneath the ocean
What are the properties of oceanic crust
Denser than continental crust and can be subducted
Where is continental crust found
Under land masses or continents
What are the properties of continental crust
Older than oceanic crust and is less often destroyed
Where are earthquakes found
Along all types of plate margins
Where are volcanoes found
Occur on constructive and destructive plate margins
What is a plate margin
Where two or more tectonic plates meet
Which plate boundary are most volcanoes located at
The pacific plate
What is a destructive plate margin
Involves an oceanic plate and a continental plate that move towards each other
How does an earthquake form at a destructive plate boundary
As the oceanic plate subduct’s under a continental plate it can get stuck causing friction and pressure to build up but once the pressure is finally released it causes seismic waves which is an earthquake
How does a volcanic eruption happen at a destructive plate boundery
When the oceanic crust subduct’s under the continental crust it goes into the mantle as it is hot it melts and forms magma the pressure of the magma builds up it then escapes through weaknesses in the rock and rises up through a composite volcano
What are eruptions at a composite volcano like
Violent with lots of steam gas and dust
Why does the oceanic plate subduct’s under the continental plate
Because it is denser
If two continental plates collide what happens
Neither can sink so the land goes upwards and forms fold mountains
