natural hazards- case studies

• The Caribbean nation of Haiti was devastated by a magnitude 7 earthquake


  12th of January 2010
• Haiti

  • Lies on the boundary between the Caribbean and North American plates
  • The 2010 earthquake occurred on the Enriquillo-Plantain Garden Fault
  • The fault is a conservative plate margin, which means the plates move alongside each other
  • The fault had been locked in tension for 250 years and all this energy being released caused a massive earthquake
• Primary impacts (haiti 2010)


  • 30,000 commercial buildings collapsing
  • Over 230,000 deaths and 300,000 injuries
  • Over 100,000 houses were destroyed
  • Many hospitals were destroyed
  • The Presidential Palace and the main port were also destroyed
• Secondary impacts (haiti 2010)


  • Over 2 million people being left homeless and without food or water
  • An increase in crime, with many shops being looted
• Immediate responses (haiti 2010)

  1. 2.6 million bottles of water being donated by the United States

  2. Temporary hospitals were set up by the Red Cross

  3. 500 UN troops and police were sent to help distribute aid and keep order, such as preventing looting of shops
• Long-term responses (haiti 2010)

  1. The International Monetary Fund approved $102 million USD in assistance for rebuilding

  2. 98% of the rubble was still unclear after six months

  3. A year later there were still 1,300 camps housing 1.6 million people
• With Haiti being a low-income country, it was not very well prepared
• There were very few earthquake resistant buildings, with many buildings and other structures being poorly built (Haiti 2010)
• Haiti 2010


  There were also very few resources to rescue or help injured people, meaning it had to heavily rely on foreign aid
• define a natural hazard

  can pose risks to people and property
• 5 types of natural hazards

  • earthquake
  • volcano
  • landslide
  • tsunami
  • tornado
• factors affecting natural hazards


  -number of people vulnerable

  -frequency

  -magnitude

  -urbanisation-> urban areas= more buildings. => more risk of more structures collapsing. so more people are at risk

  -climate change-> effects of climate change= more people at risk. e.g sea level rise= higher risk of flooding, tropical storms
• how does hazards risk increase population increase?

  more developed or more populated area, would affect the hazard risk+ more danger of injuries
• layers of the earth

  crust, upper mantle (lithosphere), lower mantle (asthenosphere), outer core and inner core
• qualities of lithosphere and asthenosphere

  -lithosphere-> like the crust, solid rock made of granite and basalt

  -asthenosphere-> hot solid, ductile, elastic and rigid. flexible and has movement
• continential crust


  granite and old. thicker, less dense and cannot be destroyed
• oceanic crust


  made of basalt, younger, more dense and thin. can be destroyed and created
• what is the hotspot

  hot spot is the hottest part of magma
• Tectonic theory: Continential Drift (Alfred Wegner 1912)

  theory states that continential landmasses were 'drifting'. coastlines looked as if they were joined together, pangea broken down into continents. earthquakes and volcanoes occur on these plate boundaries= must be moving. lithosphere divided into plates. fossils found in diff continents
• Tectonic theory: slab pull

  at destructive plate margin. denser oceanic plate pulled down in the asthenosphere under the influence of gravity. which pulls the rest of the plate along behind it.
• tectonic theory: convection current (limited evidence)


  hot core causes magma to rise in the mantle and sink towards the core when it cools. convection builds pressure and carries plates with it
• tectonic theory: ridge push/pull

  magma rises as plates move apart at constructive plate margin. magma cools to form new plate material. as it cools, becomes denser and slides down away from ridges. causes plates to move away from eachother
• primary effects:


  immediate impacts caused by the natural hazard itself
• secondary effects:


  impacts which happens later on often as a result of primary effects
• immediate responses:

  actions taken straight away to save lives, prevent suffering or property damages
• long term responses: 


  actions that goes on for months/ years after disasters
• processes at margins:

  • destructive
  • collision
  • constructive
  • conservative
• plate margins (destructive)

  converging towards eachother. oceanic and continential plates collide. denser oceanic plate subducted. sinks below continential plate into mantle. causes part of mantle to melt. magma may rise through overlying mantle and lithosphere. eventually erupts causing volcano. chance of earthquake
• plate margin: constructive

  diverging away from eachother. hot molten magma rises between the plate boundary. tectonic plate moves away due to ridge push. causing earthquake+ volcano. magma cools= new land. (on land rift valleys form)
• plate margin: conservative

  sliding parallel past eachother. pressure builds at margin of tectonic plates, are pulled along behind plate being subducted elsewhere (slab pull). friction is overcome, rock fractures= earthquake
• reducing effects of hazards:

  -earthquake proof buildings

  -practice earthquake drills (planning)

  -warning systems (protection)
• some volcanoes attract many tourists and provide jobs for locals.
• why do people live at risk from tectonic hazards?

  Economic reasons:

  -geothermal energy provide energy for the area

  -farming the nutrient-rich soil helps agriculture

  -mining provides energy and income

  -tourism creates jobs and provides income

  -it may be cheaper to stay than move
• why do people live at risk from tectonic hazards?

  Social reasons:

  -people want to stay near friends and family

  -threat may not be great enough, or people dont understand the risk

  -people are confident that the buildings will keep them safe
• haiti earthquake

  -small island in the carribean, south east of USA. capital city- port-au-prince. poorest country in the western hemisphere. GDP= $756 per capita 2019. 69+% vulnerable/exposed to natural hazards. between north america and carribean plates. HDI= 0.471. 250k deaths. 1mil homless. 115k tents=> exposed to dieases such as cholerea.
• how can we reduce hazard risks:

  mitigation: act of reducing how harmful, unpleasant or how bad something is
• prediction-> predictions made about when and where a tectonic hazard may occur

  protection-> designing buildings that will withstand tectonic hazards

  planning-> identifying and avoiding places with most risk
• 1st predicting volcanoes-> sulfer emissions, miniquakes, sattalite images

  2nd planning with volcanoes-> evac route, emergency kit, exclusion zone

  3rd protection with volcanoes-> heat resistant tiles (directs lava flow away from homes)
• 1st planning against earthquakes-> earthquake drills, emergency kits, apps and warning system

  2nd protection-> earthquake proof structures: shatter proof glass, cross structures, shock absorbers and shutters

  3rd prediction-> difficult to predict, historical records, foreshocks (mini earthquakes), animal behaviour
• preperation: haiti and japan

  Haiti:

  -no earthquake preparedness program and no warning system

  -haitis pop lives on less than $1 per day, cant afford survival kits

  Japan:

  -every smartphone is installed with an earthquake+ tsunami alert system

  -schools run regular drills