Natural Hazards Flashcards
Earthquakes Tsunamis Volcanoes Structure of the Earth
What is a tectonic plate?
The division of the Earth’s crust
What is the crust?
The outer most part of the Earth’s structure
Convection Currents
Are the movement of the Earth’s mantle that drives tectonic plates to move
The mantle
is the largest and semi - molten part of the Earth’s structure
The core
is the inner most part of the Earth’s structure.
The inner core
is solid and temperatures are 4,300 degrees Celsius
The outer core
is a liquid and is responsible for the Earth’s magnetic fields
Plate boundaries
where two or more tectonic plates meet
Continental drift
the gradual movement of the continents across the Earth’s surface through geological time
What causes Earthquakes?
Vibrations caused by the movement of the Earth at plate boundaries and at major fault lines
What are fault lines?
Cracks in the earth’s surface
What is the focus?
The point where two plates collide
What are seismic waves?
waves of force which travel through the earth from the focus of the earthquake
What is the epicentre?
The point on the Earth’s surface directly above the focus of an earthquake
What are the three types of plate boundary movement?
Conservative
Destructive
Constructive
What is a constructive plate boundary?
When the tectonic plates move apart.
What natural hazard can be formed through constructive plate boundaries?
Volcanoes, the magma seeps through into the gap however it is not very powerful
What is a destructive plate boundary?
When the oceanic and continental plate move together. The heavier oceanic plate submerges beneath the lighter continental plate.
Which two natural hazards can form through a destructive plate boundary?
Volcano - Magma rises up through cracks and erupts onto the surface.
Earthquake - Friction causes melting of the oceanic plate and may trigger earthquakes.
What is a conservative plate boundary?
A conservative plate boundary occurs where plates slide past each other in opposite directions, or in the same direction but at different speeds.
How do conservative plate boundaries cause earthquakes?
Friction is eventually overcome and the plates slip past in a sudden movement. The shockwaves created produce an earthquake.
What is a collision zone?
Where two continental plates collide into each other.Neither plate is forced under the other, and so both are forced up and form fold mountains
What is the Richter scale?
Measures the magnitude of an earthquake using a seismograph. It starts from 0 and goes up to 10.