Natural hazards Flashcards
What is a natural hazard?
A natural event that threatens people of has the potential to cause damage, destruction and death
What are the 4 different categories of hazard?
Atmospheric, geological, water based, biological
Give some physical factors affecting hazards
Magnitude, geology, level of development of the place,
Give some human factors affecting hazard risk
Population density, governments, technology
What four parts is the earth made up of?
Inner core, outer core, mantle, crust
Inside the earth, heat is released from the core which creates convection currents in where?
The mantle
Which crust is more dense: oceanic or continental ?
Oceanic
Describe the pattern of earthquakes
Generally, earthquakes are found on the plate boundaries. For example, the Nazca and South American plate boundary is a destructive plate boundary.
Describe the pattern of volcanoes
Volcanoes are usually found on constructive and destructive plate boundaries. For example, Iceland is ok the constructive plate boundary and there are usually a lot of volcanoes there.
Why do earthquakes and volcanoes mainly occur along plate margins?
Because they are caused by the friction between the two plates or the hot molten rock(magma) rising to the surface of the earth
What is an epicentre?
It’s directly above the focus. It’s where the seismic waves are the strongest. The epicentre has the most potential for damage
What is a focus?
The point at which the earthquake is occuring
Why might there not be any damage at the epicentre of an earthquake?
There might be nothing there, for example, there might only be vegetation in the area
Describe what happens at a destructive plate margin
-Oceanic and continental plate are moving towards each other
-Oceanic plate is subducted
Describe what happens at a constructive plate margin
Two plates move apart