P1- Section A - Natural hazards and tectonic hazards Flashcards
What is the difference between natural events and natural hazards ?
Natural events have no risks whereas natural hazard pose potential risks of damage to property and loss of life .
How are different types of natural hazards classified ?
Tectonic Hazards-
Atmospheric Hazards
Geomorphological hazards
Biological hazards
What are tectonic hazards ?
Such as Earthquakes or tsunamis , which involve movemnt of tectonic plates in the Earths crust .
Examples of atmospheric hazards
hurricanes
examples of geomorphological hazards
ones that occur on the earths surface , flooding , glaciers , avalanches
example of biological hazards
such as forest fires , which involve living organisms .
Howis globalwarming a cause natural hazards ?
As it is warmer , more glaciers arre melting causing sea levels to rise , causing potential tsunamis , hotter climate caused droughts heatwaves , and warmer weather incresases the tempertaure of the oceans affecting marine species and ecosytems .
How is Deforestation a cause of Natural hazards ?
There arelos of trees on slopes , heavy storms could make tress collapse causing contamination in the water as soil could get into the sea and landslides .
How is Urbanisation a cause of natural hazards ?
More crowding in places means more poeple could be effected if an Earthquake hits and more builidng on impereable surfaces can increase flooding .
Why do people live in hazardous areas ?
CANNOT MOVE
due to living expenses ,
DONT WANT TO GO
Jobs
its worth staying due to the area (fertilised area due to a volcanic eruoton)
Overconfidenn in defences against hazards
Optimistic the hazard will not happen .
What are the four layers of the Earth (In layers starting from the outside )
Crust . Mantle , Outercore , Innercore
Describe the crust
Hard outershell that is cracked , the pieces are called plates . Very thin vompared to mantle and core
Describe the Mantle
Upper is hard but bellow that is semi-molten rock , 3800 degress celcius covers the core , made of material that flows very slowly (3800 degrees c ) the upper portion of the mantle is a weak layer called the asthenosphere .
Describe the Outer Core
Liquid Iron and Nickel
Inner Core
solid very hot - up to 5500 degress celcius
What aree the two types of crust ?
Oceanic Crust and Continetal Crust
Facts about Oceanic Crust
Under the ocean
5-10km thick
It is desner (think heavier ) than continetal crust
It is continually being renewed and subducted (destroyed )
It is mainly madeof basalt , made from solidified lava
Oceanic crust is young ;kss than 200 millioon years .
Facts about Continental Crust
25-100km thick
It is less dense (2.7g/cmcubed) than the oceanic curst
Cannot sink or be destroyed
It is older than Oceanic crust - 3.8Billion years old
Mainly made of granite rocks (lower part maily basalt and diorite )
What is the Earth’s structure (inwards out )
At the center is the core , (descrbe both cores ) then mantle (describe mantle ) , outermost layer is *crust * (describe crust )
what do the crust and mantle form
They from a rigid shell on the surface of the earh called the lithosphere .
What is significant about the lithosphere
The lithosphere is broken into bits called tectonic plates which move very slowly across the upper mantle . Movement can be tracked using gps .
How do tectonic plates move
There are two theories
convecton
or slab pull (ridge push ) - more accepted explanation