Geography Flashcards
Which are the most deadly natural hazards?
Tsunami, hurricane, earthquake.
What is the structure of the earth?
Inner core, outer core, mantle and crust.
What is continental drift?
the gradual movement of the continents across the earth’s surface through geological time.
Give some evidence to support continental drift?
- 200 million years ago all the continents were all joined up. This was called the Pangaea.
- 180 million years ago the earth split into 2 continents. In the north it is called Laurasia and in the south it became Gondwanaland.
- Today earth is split up into 7 continents Australia which moved north east, South America which moved north west of the globe, Africa, North America , Antarctica and Asia.
How do tectonic plates move?
Plates at our planet’s surface move because of the intense heat in the Earth’s core that causes molten rock in the mantle layer to move. It moves in a pattern called a convection cell that forms when warm material rises, cools, and eventually sink down.
What is a destructive plate boundary?
A destructive plate boundary occurs when oceanic and continental plates move together.The oceanic plate is forced under the lighter continental plate. Friction causes melting of the oceanic plate and may trigger earthquakes. Magma rises up through cracks and erupts onto the surface.An example of a destructive plate boundary is where the Nazca plate is forced under the South American Plate.
What is a constructive plate boundary?
A constructive plate boundary, sometimes called a divergent plate margin, occurs when plates move apart. Volcanoes are formed as magma wells up to fill the gap, and eventually new crust is formed.
An example of a constructive plate boundary is the mid-Atlantic Ridge.
What is a conservative plate boundary?
A conservative plate boundary, sometimes called a transform plate margin, occurs where plates slide past each other in opposite directions, or in the same direction but at different speeds.
Friction is eventually overcome and the plates slip past in a sudden movement. The shockwaves created produce an earthquake.
This occurs at the San Andreas Fault in California.
What is an earthquake?
An earthquake is a disturbance of the earths surface that happens when a section of the earths crust is down together or shortened.
The sudden release of energy creates seismic waves that we feel as vibrates, shaking and movements on the ground.
What is a natural hazard?
Natural hazards are severe and extreme weather and climate events that occur naturally in all parts of the world, although some regions are more vulnerable to certain hazards than others. Natural hazards become natural disasters when people’s lives and livelihoods are destroyed.
