Seismicity- Case Studies

Question 1

Background facts on Haiti

Answer 1

• situated to the north of Caribbean Plate on a transform conservative plate boundary with the North American Plate moving west
• 7.0 magnitude on 12th January 2010 at 16:53 local time
• focus 13km below surface (shallow)
• epicentre 16km west of Port-au-Prince
• tremors lasted for one minute

Question 2

Primary effects in Haiti

Answer 2

• 3 million people affected
• around 230,000 identified as dead
• 300,000 injured
• 1 million homeless
• 250,000 residences and 30,000 commercial buildings collapsed or severely damaged e.g. the UN and World Bank HQs as well as schools, hospitals, government buildings
• roads, bridges, telephone lines, electricity systems damaged
• port was hit making it hard to ship in aid to the capital

Question 3

Secondary effects in Haiti

Answer 3

• spread of fire and disease
• poor living conditions and lack of sanitation:; cholera
• shortages of food and water
• small local tsunami
• one fifth of jobs lost
• 52 aftershocks in following 12 days (one was 5.9 magnitude)

Question 4

Why was Haiti so badly affected despite the magnitude not being that great

Answer 4

• shallow depth
• struck most densely populated area of country
• poorest country in the Western Hemisphere
• buildings in poor condition and not constructed to be earthquake resistant
• 3 million people live in Port-au-Prince with the majority in slum conditions after rapid urbanisation
• only one airport with one runway; the control tower was badly damaged and the port was also inaccessible
• aid piled up but lack of trucks and people to distribute it so took days to arrive
• rescue teams took up to 48 hours due to problems at the airport so local people had to dig people out with bare hands
• severe shortage of doctors meant people died of injuries such as broken limbs

Question 5

What was the building like in Haiti

Answer 5

There were building codes but they were not conformed to and so a typical finding was that insufficient steel had been used to reinforce concrete. Half of all the buildings were destroyed.

Question 6

Christchurch background facts

Answer 6

• New Zealand is a highly tectonically active country
• the South Island is on a conservative boundary between the Indo Australian and Pacific Plates though the 2011 earthquake was caused by smaller faults that ruptured, previously unknown to geologists
• a wealthy country; GDP $41 per capita
• very mountainous interior so majority live on coastal plains (where Christchurch is located); population distribution is uneven which has a disproportionate effect on the population when earthquakes hit
• built on alluvial sediment (allowing liquefaction)
• strict building codes reviewed every 10 years
• The Greendale Fault ruptured Sept 4th 2010; 7.1 at 10km deep
• The Christchurch Earthquake 22nd Feb 2011 12:30pm; 6.3
• struck at built up area; 10km SE of the city at 5km deep at lunchtime when many were on the streets

Question 7

Primary effects in Christchurch

Answer 7

• water pipes, roads, bridges, power lines, phone lines damaged
• brought down many buildings previously damaged in sept 2010
• many heritage buildings severely damaged e.g. the cathedral and Christ church’s tallest building the Hotel Grand Chancellor (which was demolished)
• extensive liquefaction; eastern parts of the city were built on a former swamp and properties were covered in thick layers of silt
• water and sewage on the streets
• house foundations cracked and buckled; many houses had to be demolished and some areas of suburbs were never recoccupied
• confusion and panic in the centre; phone lines immediately jammed
• 185 people died, thousands are injuried
• 115 died when 6 storey Canterbury Television Building collapsed
• 169 people died in the centre of the city

Question 8

Responses in Christchurch

Answer 8

• National Crisis Management Centre activated and a national state of emergency declared
• Japan, UK and other countries sent specialist rescue teams
• land use zone map drawn up in June 2011 showing red areas where rebuilding was dangerous
• Central Business District remained cordoned off more than 2 years afterwards
• electricity restored to 75% of the city within 3 days but water and sewerage systems took years to restore
• 70,000 people left the city
• Timaru, a town 157km South saw a swell in population by 20% and thousands of pupils enrolled in schools in other cities and towns
• over 1000 buildings had to be demolished including the spire of the cathedral which remains un-reconstructed

Question 9

What is the current situation in Christchurch

Answer 9

• remains a “ghost town”
• waiting for insurance payouts and planning decisions
• charities have been set up e.g. “Greening the Rubble” schemes building temporary parks on the sites of destroyed buildings
• widespread frustration with the rate of recovery

Question 10

LEDC case study and MEDC case study?

Answer 10

LEDC- Haiti

MEDC- Christchurch

Question 11

Human factors involved in Haiti

Answer 11

GDP is $1200
Life expectancy 62.51 years (20 years lower than the UK)
Total fertility rate 2.98 per woman
Literacy rate 52.9%