Nature and distribution of earthquakes

Hazards

Epicentre

• The point on the Earth’s surface that is directly above the focus where an earthquake originates

• Experiences the most intense seismic waves, damage and shaking

Types of foci

• Shallow-focus

• Intermediate-focus

• Deep-focus

Shallow-focus

• 0-70km

• Most common and dangerous

• Intense shaking

Intermediate-focus

• 70-300km

• Occurring in the mantle

• Common in subduction zones

• Less destructive than shallow but can still cause significant damage

Deep-focus

• 300-700km

• Deep in the mantle in subduction zones

• High magnitude

• Rarely destructive