Paper 1 - global hazards Flashcards
What is the epicentre of an earthquake?
the point on the Earth’s surface directly above the focus
What is the focus of an earthquake?
the point inside of the Earth’s crust where the earthquake originates
What is the ‘depth of focus’ of an earthquake?
The depth at which an earthquake occurs (distance from focus to epicentre
What is an example of a composite volcano?
Mount Fuji, Japan
What plate boundary do composite volcano’s form?
Destructive
Compare the eruptions of composite and shield volcanos
Composite volcanoes have more violent but with longer periods between them, where shield volcanos have more frequent eruptions which are less violent
What is an example of a shield volcano?
Mouna Loa, Hawaii
What plate boundary do shield volcanos form?
Constructive
What plate boundary do Fissures form?
Constructive - on fault lines
What is an example of a fissure volcano
The mid-atlantic ridge
What is the lava like in a fissure volcano?
Basaltic lava - hard, volcanic rock
What is extreme weather?
When weather is significantly different tot he norm, depends on where you are
What is the definition of a drought?
A period of time when an area has significantly less water than the norm
What are the 4 types of drought?
Meteorological, agricultural, hydrological and water supply
What is a Meteorological drought?
Lack of rain
What is an agricultural drought?
Low levels of water in soil
What is a hydrological drought?
Low levels of water in rivers and lakes
What is a water-supply drought?
When a drought has an impact on water supply and certain uses are prioritised.
What is the distribution of drought?
Mainly occur in South America, North-Africa, the Middle East and Australia.
What is water stress?
where the demand for water exceeds supply
What is water scarcity?
a limit in availability due to physical shortages or failure of institutions to provide
What is a water shortage?
the lack of sufficient water resources, including lack of safe drinking water
What are the 3 main characteristics of a tropical storm?
Sustained winds (above 120km/h), Torrential rain and storm surges
What are the necessary conditions for a tropical storm?
Ocean temperature above 27 degrees Celsius,
at least 500 km from equator (for Coriolis spin system) and ocean depth over 60m.
Why are these the necessary conditions for a tropical storm?
The storm energy comes from the moist sea air
How do tropical storms form?
When ocean temps are over 27 Degrees (C), warm air rises, creating a low pressure area
More warm air is drawn upwards creating strong winds
Air cools and sinks, water vapour condenses and forms cumulonimbus clouds which form the eye of the storm
The storm eventually dies down when t reaches land as it will on longer get energy from moist sea air
What is the troposphere?
the lowest layer of the atmosphere where weather takes place
What are the 3 cells in the tri-cellular model?
Hadley, Ferrel and Polar
What happens in the Hadley cell?
convectional moist air rises at equator (sunshine overhead), air rises, reaches tropopuase and spreads towards pole. At 30 degrees latitude, the air descends (high pressure) creating trade winds.
What happens at the Ferrel cell?
This is the ‘zone of mixing’ which is driven by the other 2 cells
What happens in the Polar cell?
At 60 degrees North or south, air is almost warm enough to rise. This air spreads to pole at tropopause, air becomes very cools and sinks, spreading outwards from pole
What are the 4 layers of the Earth’s structure?
Inner core, outer core, mantle and crust
What is the inner core made out of?
Solid iron and nickel
What is the outer core made out of?
Liquid iron and nickel