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Earthquakes (Haiti 2010 (primary effects- 180,000 homes destroyed -…
Earthquakes
Haiti 2010
primary effects- 180,000 homes destroyed - living in tents 2 years later - 5,000 schools damaged - liquefaction - transport destroyed
other possibilities - landslides and avalanches, liquefaction and panic, fear and hunger.
secondary effects- aftershocks of 6.1 magnitude - no government support - prison and headquarters destroyed - Cholera outbreak with nearly 2,000 killed - poverty and unemployment
other possibilities - lost generation, reduced life expectancy, loss of farmland and food production and issues restoring trust in neighborhoods and civil authorities.
short term response- UN organised the response - USA pledged $100M in aid - out migration - DEC sent water purification tablets to 250,000 people - UN search from France, Israel and UK - refugee camps set up
long term response- charities still working such as Oxfam and Save The Children - UN looking into rebuilding and warning systems - slums cleared - $11B for reconstruction by 2020.
causes - multi hazardous envirnoment as it is prone to tropical storms. The country is located where the Caribbean and North American plate slide past eachother in an east-west direction. Since the earthquake in 1751, scientists found that the plates were jammed as the plate moved 7mm since the last earthquake.
Japan 2011
primary effects- 1000s of homes destroyed - damage to the highway - Sendai airport closed - phone lines damaged - fuel tankers exploded
secondary effects - 150,000 homeless for over 8 weeks - 6 million homes lost power - 700 aftershocks - Fukushima meltdown - nuclear disaster
other possibilities - injuries may result in disability if not treated properly, flooding blocked rivers creating quake lakes, power cuts may affect emergency services and civil disorder, looting and direct intervention.
short term response - hospitals overcrowded - 100,000 troops for S+R - exclusion zones set up - UK sent 63 S+R specialists - iodine tablets given out and homes evacuated next to the reactor - Japanese government ordered shutdown
long term response - intensified efforts into building designs and early warning systems - 150,000 new homes - more government borrowing with a total cost of £300 billion - 2013 upgrade early warning system
causes - it happened under the Pacific Ocean. The North American plate was being dragged down by the subducting Pacific Plate and it suddenly slipped 5-10M. Japan records approximately 1500 earthquakes every year.
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They can be measured by the richter or mercalli scale. The richter scale measures the magnitude from 1-10 and uses a logarithmic scale that measures the amplitude. The mecalli scale measures the effects of the earthquake using images and witnesses from 1-12.
Seismic spatial distribution - seismic waves often occur in a lineal distribution. They appear in clusters due to chain reactions and after shocks leading in some cases to an uneven distribution. They happen very randomly and the magnitude depends on power and strength. The greater the magnitude the lower the frequancy. Some plate margins are more seismically active than others.
Causes of earthquakes - it can be caused by human activity such as mining, fracking or reservoir construction. It is mainly caused by plate tectonics. This is due to large amounts of friction that builds up along plate margins, commonly in the lithosphere. when this friction is overcome, shock waves are released. The point at which this happens at is the focus point and the epicentere is above where the most damage on the surface occurs. The further the waves spread from the epicentere, the less severe they are the further they travel.
Tsunamis - 90% of tsunamis are associated with seismic activity along the 'Pacific Ring of Fire'. This hazard is commonly referred to as tidal waves. The wave height starts very low but then increases the closer to the shore. They can travel very quickly and consist of a series of waves but the first one not always the biggest. They have a very long wave period (the time between each wave). As they approach the coast, they will slow down and pile up as a massive wall of water before breaking.
Warning signs - microquakes before the main tremor, bulging of the ground, decreasing radon gas concentrations in groundwater, raised groundwater levels, increased argon gas content in the soil and curious animal behavior.
Mitigation - new buildings, bridges, roads, pipelines and power lines can be designed to withstand the shaking. Geographic Information Systems are used to prepare hazard maps which help aid planning and development. Public education is simple as teachers are able to provide earthquake preparation checklists and practicing evacuation drills.
seismic waves - body are primary and secondary (primary are longitudinal, compressional and can pass through all physical properties. There are also secondary that are transverse, half the speed and pass through all properties. Surface waves which are either rarely or love. Rarely are circle over the surface whereas love move up and down on the surface.