Tectonic Landforms and Earthquake Flashcards
An earthquake is not a landform
Define volcano
A volcano is where liquid rock (magma) erupts through the ground. Above ground, the liquid rock is called lava.
Define earthquake
An earthquake is a sudden violent shaking of the ground, typically causing great destruction, as a result of movements of the earth’s crust or volcanic action.
Where can hot spots be found
Hawaii is above a hotspot
Hawaii is an arc of volcanic islands
Label a conservative plate margin/structure of an earthquake
Seismic waves
Plate movement, fault
Epicentre (above focus)
Focus (underground)
(look in book)
Define seismic energy
Seismic energy are the shock waves created by an earthquake
Epicentre: The point on the surface directly above an earthquake
Fault: A crack in the Earth’s crust along which plates move
Magnitude: the strength or energy of an earthquake
Focus: The point underground where the rock snaps and the earthquake starts
Define epicentre
The epicentre is the point on the surface directly above an earthquake
Define fault
A fault is a crack in the Earth’s crust along which plates move
Define magnitude
Magnitude is the strength or energy of an earthquake
Define focus
The focus is the point underground where the rock snaps and the earthquake starts
State some physical processes that can lead to earthquakes and volcanoes
Constructive plate margin
Destructive plate margin
Conservative Plate Margin
Where do most earthquakes and volcanoes occur
Most earthquakes and volcanoes occur at plate boundaries
Explain why earthquakes occur at plate margins.
[4 marks]
A destructive plate boundary is when oceanic crust moves towards continental crust. As the oceanic crust is heavier, it is subducted (forced downwards). This force and pressure can trigger earthquakes.
At conservative plate boundaries, two plates try to slide slowly past one another. When the two plates stick, pressure builds up. This pressure is then released as an earthquake.
A constructive margin is where two plates move apart. As a ‘gap’ appears between the two plates, lava can easily escape either in the form of a gentle eruption (volcano) or as a lava flow. The lava creates new oceanic crust and forms a mid-ocean ridge. Earthquakes and volcanoes can be found at constructive plate boundaries.
Earthquakes can occur at collision margins. The force and pressure from the two continental plates being pushed upwards or buckled under can trigger earthquakes.
What causes Earthquakes
Earthquakes are the sudden violent shaking of the ground. This happens because the Earth’s plates are constantly moving. Sometimes, because of friction, plates try to move and become stuck. Pressure builds up because the plates are still trying to move. When the pressure is released, it sends out huge amounts of energy in the form of seismic waves causing the Earth’s surface to shake violently.
What equipment are earthquakes measured on
A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions, and explosions.
