Natural Hazards Flashcards
(35 cards)
What is the core and the mantle made of
Core - solid iron nickel
Mantle - semi molten rock that moves very slowly
What are the two types of plates
Continental and oceanic
What’s the difference between continental and oceanic crusts
Continental crust is thicker and less dense while oceanic is thinner and more dense
What is a destructive margin
When two plates are moving towards each other
What does a destructive margin cause and how
It causes volcanoes and ocean trenches because an oceanic plate meets a continental plate and is forced down into the mantel and destroyed
What happens if two continental plates meet
The plates smash but no crust is destroyed
What is a constructive margin
Where two plates are moving away from each other, magma rises from the mantle to fill the gap and cools creating crust
What’s an example of a constructive margin
The mid Atlantic ridge where the Eurasian plate and the North American plate are moving apart
What is a conservative margin
Where two plates are moving sideways past each other,or moving in the same direction at different speeds
What do conservative margins cause
Earthquakes
What’s an example of a conservative margin
The Pacific plate moving past the North American plate
What is the focus
The point in the earth where the earthquake starts
What is an epicentre
The point of the earthquake strait above the focus
What is a drought
When conditions are drier than normal and the rainfall is below average
What happens in an area with a drought
The water supplies in the area dry up faster because the heat has increased the rate of evaporation
How long does a drought last
Depends on the area
Which areas are at the biggest risk of droughts
Areas near the equator
What are the tree ways droughts are caused
- Change in atmospheric circulation, making it doesn’t rain in the area for a long time
- Change in atmospheric circulation can also cause the annual rains to fail
- High pressure weather systems - anti cyclones - block weather systems that cause rain
What are climatic hazards
Tropical storms and droughts
What natural disasters are members of the low pressure weather system family
Hurricanes,typhoons,tropical cyclones and tornadoes
What are tropical storms
Huge storms with strong winds and torrential rain
What are earthquakes and volcanoes caused by?
Movement of tectonic plates
What are some different characteristics of s volcano
- age
- size
- height
- active or dormant
- location
- constructive or destructive
- type
- what’s ejected/erupted
- violent or gentle
- on plate margin or not
- land or underwater
What’s a dike
A side vent in a volcano
