Natural Hazards Flashcards
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
What’s a still
An underground vent in a volcano
What’s a crater
The hole at the top of the volcano
What’s special about volcanoes
They have different layers created by lava
What’s a magma chamber
The area under a volcano where magma is stored
What are the eight very important plates
- north American plate
- cocos plate
- nazca plate
- african plate
- eurasian plate
- indo - Australian plate
- antarctic plate
- pacific plate - the big boy
What’s happening between the Eurasian plate and the North American plate
They are both moving away from each other, this causes earthquakes and volcanos
What’s happening between the Eurasian plate and the indo-Australian plate
The are both colliding into each other creating earthquakes and mountains
What’s happing between the Eurasian plate and the Pacific plate
The Eurasian plate is moving towards the Pacific plate and will create earthquakes and tsunamis
Why do plates move
Plates are moving because of convection currents there help the heat rise and move the plates and the crust is made up of plates
Where is the rind of fire located
Along and between the Philippines,Pacific, indo Australian and Eurasian plates
What are the three types of volcanoes
Hotspot, destructive and constructive
