Hazards Generated By Earthquakes

Question 1

ground shaking + displacement

Answer 1

• vertical + horizontal movement of the ground
  eg Japan, Covet at lunchtime gas stoves + wooden structures -> fire spread
  experienced by locations close to epicentre
  buildings can withstand vertical better than horizontal; swaying go structures is most dangerous
  displacement of surface can disrupt natural drainage, rivers, movement of water in aquifer -> implications on public water supply + irrigation for agriculture

Question 2

what does the severity of ground shaking depend on?

Answer 2

• earthquake magnitude
• distance from epicentre
• local geology

Question 3

liquefaction

Answer 3

when an earthquake strikes an area of fine grained sands + landfill with water content
= materials lose their strengths eg riverbanks collapse + structure tilt eg Christchurch NZ 2010

Question 4

landslides + avalanches

Answer 4

regions like Himalaya-Karakoram are unstable + vulnerable to landslides -> vulnesrabitliy increased by deforestation + heavy monsoon rains
the nepalese earthquake 2015 triggered no. of landslides + avalanches caused by ground shaking

landslides disrupt transport routes in mountainous regions, movements of soil + rock can also block rivers + create natural dams + temp lakes which can threaten areas with catastrophic floods if broken eg Kashmir in 2015

Question 5

tsunamis

Answer 5

underwater earthquakes can cause the sea bed to rise which displaces water above + produces powerful waves at the surface which spread out at high velocity
due to height + long wavelength, tsunami waves can pass underneath a ship out at sea unnoticed (huge body of water)
tsunami wave rushes in as a wall of a height that can exceed 25m

Question 6

what is an earthquake?

Answer 6

a release of stress that has built up within the earth’s crust caused by tension

Question 7

what is the focus?

Answer 7

point in the earths crust where rocks fracture, releasing energy

Question 8

deaths by earthquakes 2000-2015?

Answer 8

800,000-900,000

Question 9

an example of liquefaction

Answer 9

1995 Kobe earthquake, much of port had been built on reclaimed land in Osaka Bay, world trade affected

Question 10

tsunami example

Answer 10

tsunami generated in 2004 on the coast of Aceh is est. to have delivered 1000 tonnes of water per metre of shoreline (Sumatra earthquake)