Components of an Earthquake

Key Terms:

Term	Definition
Earthquake	Shaking or vibration of the Earth's Crust
Seismologist	People who study Earthquakes
Seismograph	Machines that measure the magnitude/strength of an earthquake
Focus	Place within the crust where an earthquake occurs
Epicentre	Area on the surface directly above the focus where tremors and shock waves reach the surface first
LDC	A 'less developed country'. Characterised by low industrialisation, limited infrastructure, and lower standards of living.
Terrain	The physical features, shape, and layout of the land in a specific area.
Geology	The study of the Earth's physical structure, including rock types, layers, and processes in a specific area.
Emergency Aid	Immediate assistance provided after a natural disaster, including essential supplies like clean water, food, blankets, and medical care
Development Aid	Long-term support aimed at improving infrastructure, education, and economies, including resources like machinery, training for teachers, and engineers.
Tsunami	A series of large ocean waves caused by the displacement of large volumes of water, often triggered by undersea earthquakes, volcanic eruptions, or landslides.

Introduction to Earthquakes

What is an Earthquake?

• Created by the sudden release of energy along a fault line due to the movement of tectonic plates.
• Seismic waves/tremors that radiate out are called shock waves.
• Shock waves spread out from the focus deep within the Earth's crust.
• Directly above the focus is the epicentre where most of the destruction will take place.
• Waves that occur after the main earthquake are called aftershocks.

Categories of Earthquakes:

Shallow focus:

• Focus is found close to the surface – less than 80km from it.
• They are the most common and dangerous type of earthquake causing great destruction and loss of life.
• Occur at plate boundaries as a result of plates sinking and becoming stuck and then released which releases large amounts of energy.

Deep Focus:

• Focus is found close to the surface – less than 80km from it.
• They are the most common and dangerous type of earthquake causing great destruction and loss of life.
• Occur at plate boundaries as a result of plates sinking and becoming stuck and then released which releases large amounts of energy.