Most hazard events are measured on some kind of scale to give them a quantifiable outcome. Some scales measure only one variable and are extremely objective e.g. the Richter Scale which measures the amount of seismic energy released in an earthquake, while others measure several variables e.g. the Saffir-Simpson scale which looks at both wind speed and height of storm surge and others have a more subjective nature e.g. the volcanic explosivity index which includes visual observations. Below is a summary of some of the most common scales for measuring disasters:
The Richter Magnitude Scale
The Richter scale was developed by Charles Richter in partnership with Beno Gutenberg in 1935. Both worked at the California Institute for Technology and designed to measure differences in local earthquakes. The Richter Scale is base 10 logarithmic scale e.g. a 5.0 magnitude earthquake is ten times larger than a 4.0 magnitude earthquake. The magnitude of an earthquake is calculated the amplitude of waves. This is measured on a seismograph.
The largest earthquake ever recorded was a 9.5 in 1960 in Chile. The devastating earthquake that caused the 2004 Indian Ocean tsunami was a 9.2 and the recent earthquake (2011) that caused the Japanese tsunami was a 9.0. The USGS records the magnitude and location of most of the world's earthquakes.
The Mercalli Intensity Scale
The Mercalli Scale was based on the Rossi-Forel Scale. It was developed by the vulcanologist Giuseppie Mercalli who updated the Rossi-Forel Scale in 1884 and 1906. It differs from the magnitude of the Richter Scale because it measure the intensity of an earthquake in terms of its impacts and recognises that magnitude is not the only factor in determining this. It also considers other factors like depth of earthquake, terrain and population density.
Because the Mercalli Scale looks at a numbers of variables a weaker earthquake on the Richter Scale might have a higher Mercalli Scale than a stronger earthquake on the Richter scale. For example:
Japan Tohoku earthquake of 2011 (deaths = 18,500 - including deaths from subsequent tsunami)
Richter Scale = 9.0
Mercalli Scale = IX
Haiti 2010 Earthquake (deaths = 316,000)
Richter Scale = 7.0
Mercalli Scale = X
Volcanic Explosivity Index (VEI)
The VEI was developed by Chris Newhall of the USGS and Stephen Self of the University of Hawaii. It was develped in 1982 to look at the relative explosivity of volcanoes. The scale is opened ended and looks at the following variables:
Volume of products
Eruption cloud height
Visual qualitative observations
Like the Richter Scale the VEI is logarithmic. The largest volcano on the scale is an 8, known as a supervolcanic eruption. Its characteristics are:
More than 1,000km3 of material ejected
Plume of over 100km
Frequency of more than 10,000 years (possibly much longer)
The caldera in Yellowstone National Park is believed to be a supervolcano. An eruption is believed to be overdue at this caldera (volcano).
Saffir-Simpson Scale
The scale was developed in 1971 by engineer Herbert Saffir and meteorologist Bob Simpson. The scale actually became more widespread when Bob Simpson was replaced a head of the National Hurricane Center. The scale runs from 1-5 and officially looks at a hurricanes wind speed, pressure and storm surge. However, in 2009 the NHC tried to remove the later two variables and now wind speed is the main variable that determines a hurricanes intensity. For a tropical depression to become a tropical storm, winds must exceed 38mph (62km/hr). For a tropical storm to become a hurricane, winds must exceed 74mph (119km/hr). A category 5 hurricane must have wind speeds greater than 156 mph (250km/hr). However, some scientists have suggest that a category 6 should be introduced for hurricanes with wind speeds of over 180mph (287km/hr). With the magnitude and frequency of hurricanes likely to increase in the future, this might soon be needed. The 2005 Hurricane Katrina was a category 5 hurricane.
Palmer drought severity index (PDSI)
Developed by meteorologist Wayne Palmer in 1965 the PDSI looks at temperature and precipitation. The model attempts to look at a supply and demand model of soil moisture. Supply is fairly easy to measure (precipitation), but demand is a lot harder. Demand needs to look at temperature, evapotranspiration and recharge. Palmer has attempted to overcome these difficulties by creating an algorithm that makes approximations. Although the index is relatively good for predicting droughts over longer periods, it is not as useful for predicting short term shortages and has also been criticised because of its standardised algorithms and lack of ability to measure snow and frozen ground. On the PDSI a score of 0 is normal. A score below 0 indicates drought conditions, a score above 0 indicates wet or even flood conditions.
Haiti Earthquake (Primary and secondary hazards)
Haiti is located on the island of Hispaniola in the Caribbean. It shares the island with the Dominican Republic. The capital city of Haiti is Port-au-Prince. The whole country has a population of about of about 9.7 million and a GDP per capita of about $1100 (IMF). Haiti is part of the Caribbean archipelago which mainly lies on the Caribbean plate. Hispaniola sits upon a particularly complicated boundary. To the NW the Caribbean plate is subducting under the North American Plate. However, Haiti itself lies on more of a conservative or transform fault (like the San Andreas Fault). The fault that run through Haiti is known as the Enriquilla-Plantain Garden Fault. Because of its situation on a plate boundary the whole archipelago regularly suffers from earthquakes and many of the islands on the convergent sections also suffer from volcanoes.
Haiti suffered one of these earthquakes on 12th January 2010. It measured 7.0 on the Richter Scale (X on the Mercalli Scale) and its epicentre was about 25km west of Port-au-Prince (capital of Haiti). The Haitian government reported that 316,000 people died in the quake, 300, 000 were injured and 1 million people made homeless. It also reported 250,000 homes were destroyed and 30,000 commercial buildings destroyed (all figures from Wikipedia). Some organisations have questioned the figures and said that the number of deaths was actually a lot lower.
Not only did Haiti suffer from the primary hazard of the earthquake, but it also suffered from a number of associated secondary hazards, including; a localised tsunami that is reported to have killed three people, disease outbreaks (noticeably cholera), landslides, food and water shortages and exposure to rain and heat.
Haiti is very vulnerable to hazards for a number of human and physical factors. These include:
Situation: Haiti is located in a hazard hotspot, where there are risks from many natural disasters, including: earthquakes, hurricanes, tsunamis, floods and landslides.
Deforestation: Haiti has suffered from severe deforestation. Recent estimates suggest that only 2% of Haiti remains forested, down from about 60% in 1923. This can lead to increased landslide risk and flooding and also soil degradation and potentially famine. Haiti earthquake, Deforestation heightens landslide risk - National Geographic Article
Poverty: Haiti is the poorest country in the western hemisphere so the government and people are unable to defend and/or prepare for many of the hazards Haiti's suffers from e.g. poor building design, no coastal defences.
Healthcare and Education: The healthcare in Haiti is basic (shown by life expectancy of only 62 years). Education is also basic with adult literacy of only 62% (figures from Wikipedia). The poor levels of education and healthcare mean that more people are vulnerable because they don't know what hazards they are vulnerable or how to protect themselves and also if they are affected treatment is not always adequate.
Overpopulation: Haiti has a population approaching 10 million. High birth rates (24.4) and fertility rates (over 3) mean that the population is likely to rise further. Already the population density already stands at 362 people per km2. Overpopulation means more people are vulnerable to natural hazards like earthquakes, but also other hazards like famine and disease.
Building regulations: Haiti is a poor country with large amounts of informal settlements which are vulnerable to all sorts of hazards, ranging from floods to disease, landslides to tsunamis. Also many of the more permanent structures don't follow proper earthquake guidelines because of corruption and relaxed planning regulations. This means many buildings are vulnerable to hazards, including the Presidential Palace which partially collapsed during the recent earthquake.
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Wildfires are often called bushfire or forest fires. A wildfire differs from other fires by its extensive size, the speed at which it can spread out from its original source, its potential to change direction unexpectedly, and its ability to jump gaps such as roads, rivers and fire breaks (Wikipedia).
For wildfires to start the following conditions need to exist:
Presence of combustible fuel e.g. grass, crops or forest
Good growing climate (to grow combustible fuel) but also prolonged dry periods to make fuel dry e.g. California, Coastal Australia
Drought conditions
Windy conditions to spread flames
Wildfires can be triggered naturally or by human activity:
Natural: Lightening, volcanic eruptions, sparks from falling rocks, spontaneous combustion.
Human: Arson, discarded cigarettes, power lines, sparks from equipment, camp fires, uncontrolled slash and burn farming
Once ablaze the speed wildfires travel and spread can vary on a number of things including:
Wind speed: With a strong wind wildfires can travel up to 23km/hr. Wind can also blow hot embers ahead of the main fire to start spot fires, sometimes up to 10km away.
Topography: Wildfires travel quicker uphill than downhill
Vegetation: Grass fires burn quicker and move faster than forest fires. The drier the vegetation the could fires travel.
Oxygen supply: While fires have an abundant supply of oxygen they will continue to spread and grow.
Australia suffered a series of serious wildfires starting on and around the 7th February 2009. The fires were so widespread and devastating that the start date became known as the 'Black Saturday Bushfires'. Proceeding the fires South East Australia experienced two months of no rain, followed by 40 degree centigrade temperatures and 100km/hr winds around the 7th February. Around this date there were up to 400 separate fires in the state of Victoria. The fires were blamed for 173 deaths, 414 injuries, 11,000 livestock deaths, 3,500 properties destroyed and 445,154km2 of land burnt. In total 3,582 firefighters were sent to Victoria to try and control the blazes. Although, the wildfire conditions were created naturally and some started naturally, many more were started deliberately by arsonists. Because of the deliberate starting of the fires the then Australian Prime Minister John Rudd called the arsonists mass murders and vowed to bring them to justice.
Once wildfires have taken hold it is very hard to bring them under control. Below are some of the methods used to control fires:
Fire breaks: cutting away sections of forest to remove source of fuel
Controlled burns: Again an attempt to remove the fuel by burning away sections of forest ahead of the main fire. Fairly risky and not possible in high winds.
Removal of fuel: The collection of combustible fuel e.g fallen trees and vegetation ahead of the fire.
Sand and fire beaters: An attempt to deny oxygen to the flames. Basic and not possible with big fires.
Water and chemicals: Water and flame retardant chemicals dumped from helicopters and planes flying over fires.
Firefighters: Firefighters on the ground dousing approaching fire. Very dangerous for firefighters.
Change in weather: Hope for changes in weather, reduced winds and rain.
Evacuation: If it is impossible to bring the fires safely under control, the only tactic left is evacuation.
In areas of the world where wildfires, it is important for individuals and communities to be prepared. Management strategies include:
All structures built at least 40 metres away from main forest.
All trees (even individual) at least 10 metres away from any structure
Trees spaced out further to prevent fires from spreading so easily
Land kept damp through irrigation
Lower branches removed from tree to prevent fire ladder.
Dry material removed from under trees and forest floor
BBC - My Country Documentary (Australia Firestorm)
Hurricane Katrina v Cyclone Nargis (spatial and developmental impacts)
Sometimes, natural disasters of similar magnitude can have very different impacts depending on the location that they hit. The factors that can affect the impact include:
Population density
Time of day
Level of Preparedness
Transport and communication
Level of economic development
Below is a comparison of the impacts of two category five hurricanes; hurricane Katrina that hit New Orleans, US and Cyclone Nargis that hit the Irrawaddy Delta in Burma.
Cyclone Nargis
Hurricane Katrina
Dates
Formed: April 27th 2008
Landfall: May 2nd 2008
Dissipated: May 3rd 2008
Formed: August 23rd 2005
Landfall: August 25th 2005 (South Florida) and August 29th New Orleans
Dissipated: August 30th 2005
Location
Cyclone Nargis formed in the middle of the Bay of Bengal. It then tracked west towards India before turning north east and tracking straight to the Irrawaddy delta in Burma.
Hurricane Katrina formed as a tropical depression near the Bahamas. It then tracked west crossing the southern tip of Florida before veering north and hit Louisiana.
138,366 deaths (many believe the figure was under-reported)
20,000 - 50,000 injured
Up to 3.2 million homeless
1,833 deaths
5,000 treated at emergency triage centre in airport (injured)
Estimated 12,000 made homeless in New Orleans
Economic Loss from cyclone/hurricane
$10 billion (Nearly 53.5% of GNI based on 2008 figures)
Farming sector devastated
$108 billion (0.83% of GNI based on 2005 figures)
70,000 jobs lost (estimate based on unemployment rise)
Population
Population: 49.2 million (2008 figures)
Population density: Between 70 and 75 per km2
Population: 296.5 million (2005 figures)
Population density: 80 per km2
Population indicators
Life expectancy: 62
Birth rates: 19
Death rates: 10
Fertility rate: 2.2
Life expectancy: 78
Birth rates: 14
Death rates: 8
Fertility rate: 2
Economic Indicators
Total GNI: $18,676,320,000
GNI per capita: $379.6
% below absolute poverty line of $2: Data not released
Total GNI: $12,912,890,000,000
GNI per capita: $43,551
% below absolute poverty line of $2: 0%
Transport and Communications
% of internet users: 0.22%
% of telephone users: 1.25% (cell phones and landlines)
Motor vehicles per 1000 people: 7
Amount of paved roads: 27,000km
% of internet users: 78.2%
% of telephone users: 73% own cell phones (2005)
Motor vehicles per 1000 people: 819
Amount of paved roads: 4,148,395 km
Education and healthcare
Adult literacy: 84.7%
Primary enrollment: 98.5%
University enrollment: Data not released
Doctors per 1000 of population: 0.36
Healthcare expenditure per capita: $4.5
Infant mortality: 68.78
Adult literacy: 99%
Primary enrollment: 98.5%
University enrollment: 72.6%
Doctors per 1000 of population: 2.3
Healthcare expenditure per capita: $6,096.2
Infant mortality: 6.81
Aid
Government initially declined aid. First aid flights arrived on 7th May but rescuers found it hard to obtain visas. UK biggest single donor with about $33.5 million. The UN requested a total of $841 million in aid to help victims, but only about $190 million was ever collected from donor countries.
US also delayed asking for international help. Officially they asked the EU for help one week after the disaster. Most relief is in the form of assistance e.g. tents, food, blankets and not money. Cuba did offer to send over 1,500 doctors, but this offer was declined. In total it is estimated $854 million in aid was offered, but up to half was never taken.
In terms of magnitude Hurricane Katrina (category 5) was actually slightly stronger than Cyclone Nargis (category 4). However, in terms of deaths and damage Cyclone Nargis was actually far more devastating. The information in the table is statistical evidence that helps support some of the reasons below of why Nargis was more devastating than Katrina:
Education: Even though levels of primary enrollment are the same in the US and Myanmar, the overall literacy rates are much higher in the US. It is not only important to be able to read and write so that you can understand the risks posed by hazards and how to minimise the risks, but it is also important that as a population you are educated about hazards by the government. The US local and national government is good at educating its citizens about how to prepare and react to natural disasters. They education people in terms of evacuation plans and also educate rescuers on how to save lives and rescue people.
Transport: Car ownership is much high in the US than Myanmar (over 100 times higher). The US also has a much more extensive road network. In fact in the Irrawaddy Delta where Nargis hit there are virtually no roads and the main form of transport is by boat. The US also has a much bigger air network with established airlines like United, Delta, Continental and American. This means that people in the US were much better able to evacuate the oncoming hurricane and also rescue teams were more easily able to reach victims, thus reducing the overall number of casualties. It also allows water, food, tents, medical supplies to reach affected areas. In times of flooding helicopters are also important - the US who spends more money on its army than any other country in the world has an abundance of helicopters.
Communications: Internet and phone usage is extremely low is Myanmar, where they are both over 70% in the US. Good communications are vital in reducing casualties because it allows people to receive warnings and updates of approaching hazards as well as call for help if they have been impacted by hazards. Again the Irrawaddy Delta is very remote and will probably have even lower internet and phone ownership than the rest of Myanmar.
Healthcare: The US spends a lot more money on its healthcare than Myanmar and has significantly more doctors per person than Myanmar. Therefore it is in a much better position to treat victims of natural disasters and in a better position to reduce many of the secondary hazards like disease common with natural disasters like Nargis and Katrina.
Level of Development: The US is an MEDC and has the largest economy in the world. Myanmar is considered by most to still to be an LEDC. Because of the US's level of development it has much more money to prepare for natural hazards and a lot of money to recover from them. Countries like Myanmar often become reliant on aid in times of natural disasters - something that they were actually slow to accept.
Aid: Both countries were slow to accept aid and the US even declined aid including the offer of over 1500 doctors from Cuba. However, Myanmar's delay in accepting aid and actually declining visas to maid aid workers was much more significant because they were much less able to help themselves. By not accepting aid more victims would have died because of their initial injuries and more people would have suffered from secondary hazards like exposure and disease.
Building Design: Most people living in the Irrawaddy Delta are poor farmers and fishermen who nearly all live in temporary structures made out of things like plastic, wood and reeds which are unable to withstand the strong winds and rain associated with cyclones. On the other hand the US has strict guidelines about building regulations and although many buildings did flood in New Orleans most stood up to the winds associated with Katrina.
Defences: Even though many of the levees protecting New Orleans failed and caused significant flooding, there were actually many other levees and coastal defences that held and reduced the impact of the hurricane. In the flat Irrawaddy Delta there were virtually no defences and even many of the regions natural defences like mangroves had been removed making the region more vulnerable and increasing the number of victims.
Insurance: Most people and businesses will have insurance in the US. This means that they can afford to live in temporary accommodation if their house has been damaged and afford for totally to be repaired. Businesses can also claim for lost income and repair any damage. This means that people are able to recover much quicker and are less likely to suffer from secondary hazards and future primary hazards. In the Irrawaddy Delta in Myanmar most people would never of heard of insurance, let alone have it, meaning that they have to rebuild their houses from temporary materials and will lose significant income which may lead to secondary hazards like famine, exposure and disease.
So even though the Hurricane Katrina was one of the US's worst ever natural disasters, its impacts were not as great as Cyclone Nargis because of peoples education and the country's transport, communications and healthcare networks as well as the US's higher level of development and more stringent building regulations and defences.
Temporal Changes that have affected the impact of hazards
As well as spatial variations (i.e. between countries and regions) in the impact of hazards, there are also factors that have changed overtime (temporal). Some of these factors have increased the impacts of hazards, while others have reduced the impact. Below is a summary of the temporal changes that have changed the impact of hazards:
Growing population: The world's growing population (now $7 billion) means that there is a greater risk of drought and famine because of demand on resources, It also means diseases can spread more easily and more people live in hazardous areas e.g. near volcanoes, by rivers or on the coast.
Frequency and magnitude of hazards: The number of hazards are increasing because more people live in hazardous areas, but the frequency of hazards are also increasing because of things like climate change, deforestation and urbanisation. Things like climate change are also increasing the magnitude of hazards like drought, floods and hurricanes.
Urbanisation: More and more people are moving from rural areas to urban areas. This can mean people have better access to healthcare and education which can reduce the impacts of hazards, but it can also increase the impact of hazards because people are living in higher population densities which can aid the spread of disease and mean more people are affected by earthquakes and hurricanes that strike urban areas.
Building design: Generally building design has steadily improved and become more resistant to earthquakes, hurricanes etc. This means that less people are impacted by some hazards. However, building design can also create false security. People might believe there building is safe, bur in reality building codes have not been followed and it is still vulnerable e.g. buildings in Vam during recent Turkey earthquake.
Education: With improvements in education people are now more aware of hazards and know how to prevent them. For example, they know how to improve personal diet and hygiene to reduce disease and also how to make buildings safe against hurricanes and what to do if a tsunami is approaching
Healthcare: Ongoing improvements in healthcare have not only met less people are impacted by diseases, they have also meant more people can survive injuries caused by hazards e.g. broken limbs, infections, etc.
Hazard prediction: Organisations are now getting much better at predicting the location and or/track of hazards. Therefore organisations can give countries and communities greater warning to either evacuate and prepare. In years gone by, people may have no idea that a hurricane or flood is approaching.
Transport and communication: With improvements in communications people now hear about approaching hazards, but also hear about how to prepare and make themselves safe. They can also alert family or rescue services if they have been affected by7 a hazard. In addition im proved transport means that people can escape hazards more easily and also rescue attempts can be made e.g. helicopters can rescue flood victims.
Preparedness: Countries and communities now tend to be a lot more prepared, not only in terms of building design and hazard mapping, but also in terms of evacuation drills, medical training, rescue teams, warning sirens, etc.
Measuring Disasters
Most hazard events are measured on some kind of scale to give them a quantifiable outcome. Some scales measure only one variable and are extremely objective e.g. the Richter Scale which measures the amount of seismic energy released in an earthquake, while others measure several variables e.g. the Saffir-Simpson scale which looks at both wind speed and height of storm surge and others have a more subjective nature e.g. the volcanic explosivity index which includes visual observations. Below is a summary of some of the most common scales for measuring disasters:
The Richter Magnitude Scale
The Richter scale was developed by Charles Richter in partnership with Beno Gutenberg in 1935. Both worked at the California Institute for Technology and designed to measure differences in local earthquakes. The Richter Scale is base 10 logarithmic scale e.g. a 5.0 magnitude earthquake is ten times larger than a 4.0 magnitude earthquake. The magnitude of an earthquake is calculated the amplitude of waves. This is measured on a seismograph.
The largest earthquake ever recorded was a 9.5 in 1960 in Chile. The devastating earthquake that caused the 2004 Indian Ocean tsunami was a 9.2 and the recent earthquake (2011) that caused the Japanese tsunami was a 9.0. The USGS records the magnitude and location of most of the world's earthquakes.
The Mercalli Intensity Scale
The Mercalli Scale was based on the Rossi-Forel Scale. It was developed by the vulcanologist Giuseppie Mercalli who updated the Rossi-Forel Scale in 1884 and 1906. It differs from the magnitude of the Richter Scale because it measure the intensity of an earthquake in terms of its impacts and recognises that magnitude is not the only factor in determining this. It also considers other factors like depth of earthquake, terrain and population density.
Because the Mercalli Scale looks at a numbers of variables a weaker earthquake on the Richter Scale might have a higher Mercalli Scale than a stronger earthquake on the Richter scale. For example:
Japan Tohoku earthquake of 2011 (deaths = 18,500 - including deaths from subsequent tsunami)
Richter Scale = 9.0
Mercalli Scale = IX
Haiti 2010 Earthquake (deaths = 316,000)
Richter Scale = 7.0
Mercalli Scale = X
Volcanic Explosivity Index (VEI)
The VEI was developed by Chris Newhall of the USGS and Stephen Self of the University of Hawaii. It was develped in 1982 to look at the relative explosivity of volcanoes. The scale is opened ended and looks at the following variables:
Like the Richter Scale the VEI is logarithmic. The largest volcano on the scale is an 8, known as a supervolcanic eruption. Its characteristics are:
The caldera in Yellowstone National Park is believed to be a supervolcano. An eruption is believed to be overdue at this caldera (volcano).
Saffir-Simpson Scale
The scale was developed in 1971 by engineer Herbert Saffir and meteorologist Bob Simpson. The scale actually became more widespread when Bob Simpson was replaced a head of the National Hurricane Center. The scale runs from 1-5 and officially looks at a hurricanes wind speed, pressure and storm surge. However, in 2009 the NHC tried to remove the later two variables and now wind speed is the main variable that determines a hurricanes intensity. For a tropical depression to become a tropical storm, winds must exceed 38mph (62km/hr). For a tropical storm to become a hurricane, winds must exceed 74mph (119km/hr). A category 5 hurricane must have wind speeds greater than 156 mph (250km/hr). However, some scientists have suggest that a category 6 should be introduced for hurricanes with wind speeds of over 180mph (287km/hr). With the magnitude and frequency of hurricanes likely to increase in the future, this might soon be needed. The 2005 Hurricane Katrina was a category 5 hurricane.
Palmer drought severity index (PDSI)
Developed by meteorologist Wayne Palmer in 1965 the PDSI looks at temperature and precipitation. The model attempts to look at a supply and demand model of soil moisture. Supply is fairly easy to measure (precipitation), but demand is a lot harder. Demand needs to look at temperature, evapotranspiration and recharge. Palmer has attempted to overcome these difficulties by creating an algorithm that makes approximations. Although the index is relatively good for predicting droughts over longer periods, it is not as useful for predicting short term shortages and has also been criticised because of its standardised algorithms and lack of ability to measure snow and frozen ground. On the PDSI a score of 0 is normal. A score below 0 indicates drought conditions, a score above 0 indicates wet or even flood conditions.
Haiti Earthquake (Primary and secondary hazards)
Haiti is located on the island of Hispaniola in the Caribbean. It shares the island with the Dominican Republic. The capital city of Haiti is Port-au-Prince. The whole country has a population of about of about 9.7 million and a GDP per capita of about $1100 (IMF). Haiti is part of the Caribbean archipelago which mainly lies on the Caribbean plate. Hispaniola sits upon a particularly complicated boundary. To the NW the Caribbean plate is subducting under the North American Plate. However, Haiti itself lies on more of a conservative or transform fault (like the San Andreas Fault). The fault that run through Haiti is known as the Enriquilla-Plantain Garden Fault. Because of its situation on a plate boundary the whole archipelago regularly suffers from earthquakes and many of the islands on the convergent sections also suffer from volcanoes.
Haiti suffered one of these earthquakes on 12th January 2010. It measured 7.0 on the Richter Scale (X on the Mercalli Scale) and its epicentre was about 25km west of Port-au-Prince (capital of Haiti). The Haitian government reported that 316,000 people died in the quake, 300, 000 were injured and 1 million people made homeless. It also reported 250,000 homes were destroyed and 30,000 commercial buildings destroyed (all figures from Wikipedia). Some organisations have questioned the figures and said that the number of deaths was actually a lot lower.
Not only did Haiti suffer from the primary hazard of the earthquake, but it also suffered from a number of associated secondary hazards, including; a localised tsunami that is reported to have killed three people, disease outbreaks (noticeably cholera), landslides, food and water shortages and exposure to rain and heat.
Haiti is very vulnerable to hazards for a number of human and physical factors. These include:
Haiti Devastated by Massive Earthquake - BBC article
Cholera death toll jumps in Haiti - BBC article
Haiti quake survivors spend second night in streets - BBC article
Strong aftershock shakes Haiti, week after earthquake - BBC article
Why did so many people die in Haiti's Quake - BBC article
Why did Fewer die in Chile's earthquake than Haiti's - BBC article
Australia Wildfires (Manmade Disaster)
For wildfires to start the following conditions need to exist:
Wildfires can be triggered naturally or by human activity:
Natural: Lightening, volcanic eruptions, sparks from falling rocks, spontaneous combustion.
Human: Arson, discarded cigarettes, power lines, sparks from equipment, camp fires, uncontrolled slash and burn farming
Once ablaze the speed wildfires travel and spread can vary on a number of things including:
Australia suffered a series of serious wildfires starting on and around the 7th February 2009. The fires were so widespread and devastating that the start date became known as the 'Black Saturday Bushfires'. Proceeding the fires South East Australia experienced two months of no rain, followed by 40 degree centigrade temperatures and 100km/hr winds around the 7th February. Around this date there were up to 400 separate fires in the state of Victoria. The fires were blamed for 173 deaths, 414 injuries, 11,000 livestock deaths, 3,500 properties destroyed and 445,154km2 of land burnt. In total 3,582 firefighters were sent to Victoria to try and control the blazes. Although, the wildfire conditions were created naturally and some started naturally, many more were started deliberately by arsonists. Because of the deliberate starting of the fires the then Australian Prime Minister John Rudd called the arsonists mass murders and vowed to bring them to justice.
Once wildfires have taken hold it is very hard to bring them under control. Below are some of the methods used to control fires:
In areas of the world where wildfires, it is important for individuals and communities to be prepared. Management strategies include:
Two Quizzed Over Australia Fires - BBC article
Australian PM: Wildfire arson is mass murder - CNN article
Suspect Charged Over Deadly Australian Bushfires - Guardian Article
BBC - My Country Documentary (Australia Firestorm)
Hurricane Katrina v Cyclone Nargis (spatial and developmental impacts)
Sometimes, natural disasters of similar magnitude can have very different impacts depending on the location that they hit. The factors that can affect the impact include:
Below is a comparison of the impacts of two category five hurricanes; hurricane Katrina that hit New Orleans, US and Cyclone Nargis that hit the Irrawaddy Delta in Burma.
Cyclone Nargis
Hurricane Katrina
Landfall: May 2nd 2008
Dissipated: May 3rd 2008
Landfall: August 25th 2005 (South Florida) and August 29th New Orleans
Dissipated: August 30th 2005
135mph (215kph)
Pressure 962 millibars
175 mph (280kph)
Pressure: 902 millibars
20,000 - 50,000 injured
Up to 3.2 million homeless
5,000 treated at emergency triage centre in airport (injured)
Estimated 12,000 made homeless in New Orleans
Farming sector devastated
70,000 jobs lost (estimate based on unemployment rise)
Population density: Between 70 and 75 per km2
Population density: 80 per km2
Birth rates: 19
Death rates: 10
Fertility rate: 2.2
Birth rates: 14
Death rates: 8
Fertility rate: 2
GNI per capita: $379.6
% below absolute poverty line of $2: Data not released
GNI per capita: $43,551
% below absolute poverty line of $2: 0%
% of telephone users: 1.25% (cell phones and landlines)
Motor vehicles per 1000 people: 7
Amount of paved roads: 27,000km
% of telephone users: 73% own cell phones (2005)
Motor vehicles per 1000 people: 819
Amount of paved roads: 4,148,395 km
Primary enrollment: 98.5%
University enrollment: Data not released
Doctors per 1000 of population: 0.36
Healthcare expenditure per capita: $4.5
Infant mortality: 68.78
Primary enrollment: 98.5%
University enrollment: 72.6%
Doctors per 1000 of population: 2.3
Healthcare expenditure per capita: $6,096.2
Infant mortality: 6.81
In terms of magnitude Hurricane Katrina (category 5) was actually slightly stronger than Cyclone Nargis (category 4). However, in terms of deaths and damage Cyclone Nargis was actually far more devastating. The information in the table is statistical evidence that helps support some of the reasons below of why Nargis was more devastating than Katrina:
Education: Even though levels of primary enrollment are the same in the US and Myanmar, the overall literacy rates are much higher in the US. It is not only important to be able to read and write so that you can understand the risks posed by hazards and how to minimise the risks, but it is also important that as a population you are educated about hazards by the government. The US local and national government is good at educating its citizens about how to prepare and react to natural disasters. They education people in terms of evacuation plans and also educate rescuers on how to save lives and rescue people.
Transport: Car ownership is much high in the US than Myanmar (over 100 times higher). The US also has a much more extensive road network. In fact in the Irrawaddy Delta where Nargis hit there are virtually no roads and the main form of transport is by boat. The US also has a much bigger air network with established airlines like United, Delta, Continental and American. This means that people in the US were much better able to evacuate the oncoming hurricane and also rescue teams were more easily able to reach victims, thus reducing the overall number of casualties. It also allows water, food, tents, medical supplies to reach affected areas. In times of flooding helicopters are also important - the US who spends more money on its army than any other country in the world has an abundance of helicopters.
Communications: Internet and phone usage is extremely low is Myanmar, where they are both over 70% in the US. Good communications are vital in reducing casualties because it allows people to receive warnings and updates of approaching hazards as well as call for help if they have been impacted by hazards. Again the Irrawaddy Delta is very remote and will probably have even lower internet and phone ownership than the rest of Myanmar.
Healthcare: The US spends a lot more money on its healthcare than Myanmar and has significantly more doctors per person than Myanmar. Therefore it is in a much better position to treat victims of natural disasters and in a better position to reduce many of the secondary hazards like disease common with natural disasters like Nargis and Katrina.
Level of Development: The US is an MEDC and has the largest economy in the world. Myanmar is considered by most to still to be an LEDC. Because of the US's level of development it has much more money to prepare for natural hazards and a lot of money to recover from them. Countries like Myanmar often become reliant on aid in times of natural disasters - something that they were actually slow to accept.
Aid: Both countries were slow to accept aid and the US even declined aid including the offer of over 1500 doctors from Cuba. However, Myanmar's delay in accepting aid and actually declining visas to maid aid workers was much more significant because they were much less able to help themselves. By not accepting aid more victims would have died because of their initial injuries and more people would have suffered from secondary hazards like exposure and disease.
Building Design: Most people living in the Irrawaddy Delta are poor farmers and fishermen who nearly all live in temporary structures made out of things like plastic, wood and reeds which are unable to withstand the strong winds and rain associated with cyclones. On the other hand the US has strict guidelines about building regulations and although many buildings did flood in New Orleans most stood up to the winds associated with Katrina.
Defences: Even though many of the levees protecting New Orleans failed and caused significant flooding, there were actually many other levees and coastal defences that held and reduced the impact of the hurricane. In the flat Irrawaddy Delta there were virtually no defences and even many of the regions natural defences like mangroves had been removed making the region more vulnerable and increasing the number of victims.
Insurance: Most people and businesses will have insurance in the US. This means that they can afford to live in temporary accommodation if their house has been damaged and afford for totally to be repaired. Businesses can also claim for lost income and repair any damage. This means that people are able to recover much quicker and are less likely to suffer from secondary hazards and future primary hazards. In the Irrawaddy Delta in Myanmar most people would never of heard of insurance, let alone have it, meaning that they have to rebuild their houses from temporary materials and will lose significant income which may lead to secondary hazards like famine, exposure and disease.
So even though the Hurricane Katrina was one of the US's worst ever natural disasters, its impacts were not as great as Cyclone Nargis because of peoples education and the country's transport, communications and healthcare networks as well as the US's higher level of development and more stringent building regulations and defences.
Hurricane Katrina in depth - BBC
Hurricane Katrina - Special Reports - BBC
Cyclone Nargis - Special Reports - BBC
Temporal Changes that have affected the impact of hazards
As well as spatial variations (i.e. between countries and regions) in the impact of hazards, there are also factors that have changed overtime (temporal). Some of these factors have increased the impacts of hazards, while others have reduced the impact. Below is a summary of the temporal changes that have changed the impact of hazards:
Icelandic Volcanoes
Christchurch earthquake mapped from space - BBC article