Hazards caused by earthquakes

Question 1

What is liquefaction and what happens during it?

Answer 1

• vibrations of smaller particles causing ground shaking & displacement
• foundations give way
• riverbanks collapse
• structures tilt & sink

Question 2

How are landslides & avalanches caused and what effects do they cause?

Answer 2

• caused by slope failure
• effects mountainous regions e.g. Himalayan range
• can block transport routes
• can create temporary lakes (Quake lakes) which can breach and flood areas downstream.

Question 3

What are tsunamis and how do they occur?

Answer 3

• river bed rises
• displaces water above
• creates powerful waves on the surface
• typical wave height 1m (increases nearer the shore) & wavelength of 200km
• caused by under-water earthquakes or ocean landslides