Earthquakes: What are effects/aftermath of earthquakes?

Question 1

Effects of earthquake

Answer 1

1. collapse/destruction of infrastructure
2. fires
3. destruction of properties
4. disruption of services
5. landslides
6. spread diseases
7. tsunamis
8. loss of lives
9. economic losses

Question 2

Collapse/destruction of infrastructure

Answer 2

• EQ may cause cracks to form in infrastructure e.g. roads, bridges
• infrastrucutre in certain places are not designed to withstand EQ, infrastructure collapses

Question 3

Fires

Answer 3

• EQ may rupture gas pipes, gas provides fuel to start fires
• EQ may also expose electrical cables which may ignite flammable items e.g. gas, oil, chemicals, plastics
• fires spread quickly over large areas, esp if got strong winds; firemen dont have water supply due to ruptured water pipes
• e.g. Kobe EQ, Japan (1995)

Question 4

Destruction of properties

Answer 4

• EQ can cause widespread destruction to many homes
• ppl may become homeless after disaster
• reside at temp shelters while their homes r being rebuilt

Question 5

Disruption of services

Answer 5

• EQ can disrupt services such as supply of electricity, gas and water
• vibrations on ground can snap pipes and break cables which may cause an outbreak of fires
• communication services like television broadcasts, telephone connections may also be affected

Question 6

Landslides

Answer 6

• shaking of ground during EQ can weaken slopes of hills and mountains
• unstable slopes lead to landslides
• landslides refer to the downslope movements of soil, rock and vegetation debris from a slope
• mudflows may also occur when heavy rainfall saturates soil , causing mixed soil debris to flow down slope
  e. g Taiwan Keelung, 2010, landslide onto highway

Question 7

Spread of diseases

Answer 7

• usually after EQ, many left homeless, put up in temp shelters like schools and tents
• shelters overcrowded, lack proper sanitation, lead to rapid spread of diseases e.g cholera, typhoid
• dead bodies of those killed in EQ, poisonous materials from broken sewage pipes pollute water supplies
• spread of water-borne diseases/mosquito-borne diseases
• e.g. tent city set up in Nepal immediately after 2015 EQ
• homes destroyed, unsafe due to aftershocks
• lived in tents in open fields

Question 8

Tsunami

Answer 8

• refers to unusually large sea wave, may be caused by following:
• movement of seafloor during EQ at subduction zones
• explosive underwater volcanic eruption
• landslide above sea lvl, causes materials to plunge into water (landslides may be due to EQ or volcanic eruptions

Question 9

how a tsunami is formed

Answer 9

1. formation of tsunami waves starts when seismic energy from an offshore EQ forces out a mass of sea water
2. tsunami waves may start at a height of less than 1m, wave length 100-150km, speeds of 800km/h, may be undetected
3. when reaching shallower water, greater friction slows waves, force them to increase in height
4. at pt of impact on coast, tsunami waves could be travelling at 30km/h to 50km/h, may reach heights of arnd 15m
5. sometimes sea recedes from coast b4 advancing onshore, happens few min before tsunami reaches shore
   - recedes as water first rushes to fill void caused by movement of sea floor
   - water then forced out again soon afterwards, resulting in a tsunami

Question 10

tsunami example

Answer 10

• can travel long distances, cause widespread destruction at coastal areas when sweeps inland
• 2004, 9.2 magnitude EQ occurred in Indian Ocean
• triggered tsunami, caused damage to coastal communities in 12 countries
• most damage in low lying coastal areas of western Sumatra, Indonesia

Question 11

Loss of lives

Answer 11

• loss of lives may be resulted directly from fires, landslides, tsunamis or collapse of infrastructure
• might have survived EQ but eventually die as couldn’t receive emergency relief in time (first aid)
• aftershocks (tremors that occur after main EQ) occur and cause more death

Question 12

Economic losses

Answer 12

• destruction of infrastructure will affect businesses in area, economic loss
• gov has to channel large amts of money int rebuilding country/affected area, cannot provide other goods and services
• jobs lost (esp fishermen, farmers as jobs dependent on physical environment)
• tourists avoid visiting EQ prone area, fear of re-occurrence of another EQ or tsunami
• tourism industry disrupted, may not contribute much to revenue of country