Global Hazards Flashcards
What are the 4 structures of the earth called?
1 - Inner core
2 - Outer core
3 - The mantle
4 - The crust
What is the inner core made up of?
Its sold and its made up of iron and nickel
What temperature can the inner core reach?
5500*c
What is the outer core made up of?
It is a liquid layer and is made out of iron and nickel
How thick is the mantle?
2900km
What is the mantle made up of?
Semi-molten rock called magma
Is the rock in the mantle soft or hard?
The rock is harder in the upper parts but then in the lower parts it is soft and begins to melt
How thick is the crust?
0 - 60km
What state is the rock in the crust?
It is hard
What are the two different types of crust?
1 - Continental crust
2 - Oceanic Crust
What creates convection currents?
Heat rising and falling inside the mantle
What are convection currents generated by?
Radioactive decay in the core
What do plate tectonics create?
Earthquakes and volcanoes
What happens at a tensional, constructive or divergent boundary?
The plates move apart
What happens at a compressional, destructive or convergent boundary?
The plates move towards each other
What happens at a conservative or transform boundary?
The plates slide past each other
What can a destructive boundary also be called?
A collision boundary
What are the 3 atmospheric cells called?
Hadley, Ferrrel and the polar cell
What is the largest atmospheric cell called?
Hadley
Between what *C is the Hadley cell?
30 - 40*C North and South
What is the middle atmospheric cell called?
The ferrel cell
Between what *C is the ferrel cell?
60 - 70*C
What is the smallest and weakest atmospheric cell?
The polar
What *C is the polar cell?
90*C
What temperatures does El Nino create?
Warmer
What temperatures does La Nina create?
Cooler
How long do La Nina and El Nino episodes last?
9 - 12 months
Which occurs more La Nina or El Nino?
El Nino
Which countries get warmer due to El Nino?
Australia and North America
What are the physical causes of tropical storms?
They are over tropical and sub-tropical water between 5 - 30C North and South of the equator. The surface ocean above 26.5C & depth of at least 50 - 60m, and at least 500m away from the equator so Coriolis effect is strong enough to spin weather systems.
What are some other names for tropical storms?
Cyclones, Hurricanes and Typhoons
Is a tropical storm at high or low pressure?
Low
How high do the wind speeds need to be to be classified as a tropical storm?
75mph
What is the centre of the storm called?
The eye
What is the most destructive part of the storm called?
The eye wall
How fast to the wind speeds need to be to be classified as a grade 5 hurricane?
155mph
What are the physical causes of drought?
El Nino brings descending air & high pressure causing drought.
What increases as global temps increase?
Evaporation
What happens in constructive plate boundaries?
The plates move apart, the magma seeps up through the fissures , this faults and cools instantly causing solified rock, and also a shield volcano in the mid-Atlantic ridge
What happens in destructive plate boundaries?
The plates move towards each other - oceanic & continental and oc sub ducts as denser oc melts in the mantle causing a composite volcano. On the Eurasian plate
What happens in conservative plate boundaries?
They move along side each other, earthquakes can only be on the same side or opposite, sliding past one another e.g. on the San Andreas fault line
What happens in destructive collision plate boundaries?
When earthquakes only moving towards each other at the same densities, which buckle upwards anticline + syncline. The geosyncline sedimentary compressed layers fold mountains
What is a hotspot?
A fixed point in the mantle which create intense heat in a mantle pume. The area of hot magma which are small and long-lasting which sustain volcanic activity. The magma erupts through the crust which then the pume reaches the crust causing the crus to dome and crack.
Where is Haiti?
In the northern hemisphere near Jamaica and Cubs
Which plate boundary is Haiti on?
The Caribbean
What type of plate boundary is Haiti on?
Destructive
How many were made homeless due to Haiti?
1 million