1.1 Case studies Flashcards
Indian Ocean Tsunami 2004 - description
- 26th December 2004
- hypocentre 160km away from Sumatra, Indonesia
- first waves arrived 20mins after quake
- 800km/h waves
Indian Ocean Tsunami 2004 - causes
under sea 9.2 magnitude earthquake caused by subduction of Indian plate under Burma plate
Indian Ocean Tsunami 2004 - Social Impacts
- No tsunami warning system in place
- 300,000 deaths
- 1.7 million left homeless
- Wide spread of disease (cholera and dysentery) through mixing sea water with sewage
- 6 million people requiring emergency aid
Indian Ocean Tsunami 2004 - economic impacts
- loss of earnings from tourism
- fishing industry damaged through destruction of ports, boats, equipment
- destruction of crops and farmland by seawater
- transport links damaged
Indian Ocean Tsunami 2004 - environmental impacts
- mangrove forests damaged
- 8 million litres of oil leaked from oil plants in Indonesia
- coral reefs damaged/destroyed
describe the Nepal Earthquake
- 25 April 2015
- 7.9 on Richter scale
- depth of 8.2km
- Destructive plate margin
- Indo-Australian plate colliding with Eurasian Plate
- interplate
Nepal Earthquake - secondary impacts
- Landslides and avalanches which blocked roads and hampered relief efforts
- Avalanche on Mt Everest killed 19 people
- Avalanche in the Langtang reagion left 250 missing
- Landslide blocked River Kaii Gandaki - which caused flooding in capital
- 9000 deaths
- 22,000 injuries
- $10bn in damages
describe the Gujurat earthquake
- 2001
- intraplate
- 7.7 magnitude
- in northern India
- along a rift fault associated with India + Eurasian plate boundary
Impacts of Gujurat earthquake
- 13-20,000 deaths
- 167,000 injured
- 340,000 buildings destroyed
Eyjafjallajokull 2010 - description
- stratovolcano - explosive eruptions associated with the mid-atlantic ridge
- prior to eruption, 5000 smaller earthquakes recorded near to the volcano’s crater, located beneath a glacier
- 14th April 2010, erupted from main crater in rthe middle of the glacier
Primary impacts of Eyjafjallajokull eruption
- 150m ice cap melted causing flooding
- 800 people evacuated
- 20 farms destroyed
- schools and businesses closed
- damage to crops and livestock
Secondary impacts of Eyjafjallajokull eruption
- jokulhaup flooding damaged homes
- costs of repairing flood defences
- long-term increased tourism and businesses - 1.7million tourists came as a result
- Roads bulldozed to allow flood water to reach sea
- European travel industry had £1.7bn losses
- 6 flightless days
- London lost £102mn of tourist income
Describe the Mt. St. Helens eruption.
- located in Washington state
- deadliest volcanic event in US history
- along subduction zone of Juan de Fuca and North American plates
- plinian eruption
- VEI = 5
- volcano continuously active until 2008
Mt. St. Helens’ 1980 eruption
- What were the precursor events leading up to the eruption that alerted geologists?
- small earthquakes in March 1980
- frequency of high magnitude earthquakes increased to about 8 per day
- phreatic eruptions (steam eruptions)
- formation of new crater at summit of volcano
- surface deformation due to accumulation of magma at shallow depths
Mt. St. Helens’ 1980 eruption
- What caused the May 18th lateral blast?
- 5.1 magnitude earthquake directly beneath volcano and northern slope collapsed, causing large debris avalanche
- sudden pressure change led to expansion of volcanic gases in the underlying magma
- culminated in a northward-directed lateral blast