Earthquake processes and associated risk

Question 1

What is Ground shaking and what are its hazards

Answer 1

Shaking of the ground as a result of passing of seismic waves, it presents the greatest risk to humans as buildings can collapse and the destruction of infrastructure

Question 2

What is Liquefaction and why is it dangerous

Answer 2

Loose sediment such as sand and silt combine with groundwater and behave like a fluid or quicksand. It can cause foundations of buildings to sink and collapse after earthquake water sinks into the ground and sets in place

Question 3

What are Landslides and why are they dangerous

Answer 3

Earthquakes generate stresses that make weak slopes fail, triggering landslides as well as rockfalls and avalanches.
Landslides significantly increase death tolls and prevent areas from receiving necessary first aid.
In 1970 and earthquake 25km of the coast of Peru generated a landslide on Mt Huascran 130 km away and added 20,000 people to the death toll

Question 4

What are tsunamis and why are they dangerous

Answer 4

Caused by a shallow focus(the points where the rocks fracture)
undersea earthquake creating a sudden rise or fall in the oceans surface, displacing water above it. Ocean waves spread out from the epicentre travelling at hundreds of miles per hour
Tsunamis can travel over 10km inland destroying everything in there way. They are the second deadliest effect of earthquakes

Question 5

Primary effects of earthquakes on the environment

Answer 5

Landslides, Liquefaction and tsunamis
Destruction to buildings, roads, railways, power supplies and water and sewage systems
All occur locally/ regionally

Question 6

Primary effects of earthquakes on the demographic

Answer 6

Earthquakes killed over 804,000 people between 2000 and 2017
Many people left injured
Local affects

Question 7

Secondary effects of earthquakes on the environment

Answer 7

Damage and flooding resulting form primary impacts
Damaged power lines creating mixed with damaged gas reserves generate fires
Local affects

Question 8

Secondary effects of earthquakes on the demographic

Answer 8

Loss of personal belongings
Loss of livelihood and increased unemployment
Spread of disease from contaminated water supplies