A2 - Hazardous Case Studies

Question 1

Vajont Dam, Italy

Answer 1

• 9th October 1963
• clay (impermeable) underlying limestone
• heavy rainfall - caused tsunami like flooding at night
• 2,000 died in Piave valley
• 860ft high and 30 billion gallons of water

Question 2

California

Answer 2

• intense rainfall
• EQs @ San Andreas Fault
• Steep relief
• soft/poorly consolidated rock
• oil and water extraction causes M.M

Question 3

Tornado + dust storms

Answer 3

• March 15th-16th 2025
• 34 faitalities - highest in Missouri
• 50 homes lost to fires in Oklahoma
• 150 wildfires, 83 mph winds
• 170,000 acres burnt

Question 4

Tornado measurements and tornado alley

Answer 4

speeds from 65mph (EF0) to over 200mph (EF5)
Fujita person scale
75% of USA’s 1200 tornadoes happen here
moist air from Gulf of mexico meet cold air from rockies/canada
mesocyclone

Question 5

Lake Nyos, Cameroon, 1986

Answer 5

• 2km wide and 200m deep
• 1.6 million tons of co2 released
• 1740 people and 3500 livestock soffocated
• clouds 50 m thick and 70km/h
• caused by 3 things - deep volcanic eruption, EQ or change in water temp
• degassing pipe installed

Question 6

Mount St Helens, 1980, USA

Answer 6

• Cascade Mt range, stratovolcano
• trigger was a 5 magnitude EQ
• debris avalanche at 300 degress and travelled north vat 400km/h
• $481 million in compensationand clearance
• 57 people died, 7000 animals and 1 million salmon
• 30km radius of flattened tress

Question 7

E15, Iceland, 2010

Answer 7

• stratovolcano with phreatomagnetic activity
• 9km ash plume
• $5 billion in air travel losses, 100,000 flights cancelled and 10 million passengers
• global impact more than local
• 3-9 days disturbance

Question 8

Nevado del Ruiz, Colombia, 1985

Answer 8

• stratovolcano, steep sides + v.viscous
• ring of fire - Andes MT range - 4 faults
• 70% of Amero destroyed in valley
• pyroclastic flows from glaciers and snows - lahars at 50km/h
• 23,000 deaths
  government refused to listen to international aid and monitoring

Question 9

Aberfan disaster, wales, 1966

Answer 9

• slurry of coal waste due to 3-6mm of rainfall
• 50yrs of mining debris
• 147 killed, 116 were children
• National coal board new of the dangers and 100,000m3 of debris
• £150,000 to rebuild from government and £2 million donation

Question 10

Fukashima, tsunami, 2011, Japan

Answer 10

• maginitude 9 EQ with 8 min warning
• peaked at 40.5m and travelled 9.6km in land
• 16,000 deaths
• $35 billion in damages
• Sendai - $1million in damages with 225,000 forced to live in shelters

Question 11

Moore, Oklahoma, 20th May 2013

Answer 11

• F5 tornado - touched down for 16 mins
• occured at 3pm so children were still at school - Braiarwood + Plaza Tower
• 24 killed
  $2 billion in damages
  17 mile long path and 1.3 miles wide

Question 12

Haiti, 2010, 12th January

Answer 12

• 7 magnitude
• no major EQ since 1751
• major hurricanes in 2004/8/10 so not recovering from them - park model
• 300,000 died
  60% of buildings with no codes
• corrupt government and mismanaged $4billion in aid

Question 13

Christchurch, 2010

Answer 13

• 7.1 magnitude
• slipped 4m, no casulties
• aftershocks damaged Christchurch
• Marlbourough fault created from Greendale Fault

Question 14

Christchurch, 2011

Answer 14

• 6.3 magnitude
• 5km focus @ midday
• $28 billion in damages - liquefaction + seismic lensing
• 181 people died, 2000 injured
• temporary housing + 300 auz police

Question 15

Cyclone Nargis, 2008, Myanmar

Answer 15

• bay of Bengal - 38,000 hectares of mangroves destroyed with 5m storm surge
• 4 hurricane equivilent at 217km/h
• no monitoring and india gave a 48hr warning
• 95% of buildings on the Irawwadi delta collapsed
• 140,000 deaths - no severity in warnings given

Question 16

Hurricane Katrina, 2005, USA

Answer 16

• New Orleans on floodplain of Mississippi
• category 3
  1,836 deaths and $300 billion in damages
• 8m storm surge
• it caused 62 tornadoes in 8 states
• 10.8 million gallons of oil spilled in gulf of mexico

Question 17

Montroc + Chamonix Alps, 1999

Answer 17

• Feb 9th 1999
• killed 12 people and destroyed 14 chalets
• avalanche reaching 100mph
• caused by heavy snowfall and unstable snow layers
• one of the deadliest avalanches in french alps - more zoning

Question 18

Po Shan Road, 1972 June

Answer 18

• 71 deaths
  -twice average rainfall in one day
• Hamilton Court
• 2 day event
• 10 second mass movement
• brought down a 12-storey tower block
• sheet pulling was distorted so couldn’t support hill

Question 19

Hong Kong Slope management

Answer 19

• geotechnical engineering offices monitoring 57,000 slopes
• landslip and mitigation began in 1977 - landslide warning system
• landslide risk reduced by 50% since 1977
• rules and private owners need to maintain their own slopes if not it is a year imprisonment or $500,000HK fine
• matting with vegetation and surface drainage