Natural hazards:A hazard is something that is a potential threat to human life or property
Natural hazards can be divided into three types
Geophysical hazards: caused by processes in the lithosphere. Includes tectonic hazards, e.g. earthquakes, volcanic eruptions, landslides and tsunamis
Atmospheric (or hydrometeorological) hazards: caused by climatic processes. Include tropical cyclones, storms, droughts, extremes of hot or cold weather and wildfires
Hydrological hazards: caused by water movement. Includes floods and tsunamis
Disaster:
A disaster is when a hazard occurs and has significant impact on a population
A threshold a disaster happens will be different for different countries, e.g. a hazardous event may be considered a disaster when there are: deaths of 10 or more people, 100 or more people affected at least US $1 million lost economically
A mega disaster has a regional or global impact
Different countries or communities will define a disaster differently, they are said to have occurred when countries or communities can no longer cope with the challenges that the hazardous event has created
Threshold is the intensity or magnitude level natural hazard would have to surpass to be considered a disaster
The Degg model suggests that a disaster occurs where a natural hazard event meets a vulnerable population. The greater the natural hazard event, and the more vulnerable the people, the greater the disaster
Resilience is the capacity for a community to cope with and recover from a natural disaster. This indicates any system in place to manage a natural hazard once it has occurred, and any pre-planning done to reduce the number of people at risk
Vulnerability is the level to which a community or geographical area will be damaged or affected by the occurrence of a hazard. The vulnerability of a community relates to its level of hazard preparedness
Different communities experience the impacts of disasters in very different ways. This is largely due to different places having different levels of development
Some communities have a higher level of resilience due to their awareness of natural hazard risks. They may acknowledge potential hazards and act to limit the damage that a natural hazard event could cause
Communities that have a low resilience and high vulnerability will have a lower disaster threshold. This means a hazard is more likely to be a disaster in that community
The vulnerability of a community can be determined by the factors below:
Location in relation to topographical features
Location in relation to the site of the hazard
Isolation from/access to other communities
Age and gender structure of their population
Level of urbanisation and population density
Degree of poverty/wealth of population
Level of education and literacy rate
This means that the vulnerability of a community to natural hazards can be determined before a natural hazard occurs
A risk of potential exposure to a disaster. Risk is a complex idea based on a country’s vulnerability, resilience and the nature of the hazard itself. The unpredictable nature of hazards means that there is always an element of risk, and so people always have a degree of vulnerability
The Hazard Risk Equation is a way of trying to quantify the different factors at play in determining the risk that a natural disaster poses. Countries are at a greater risk if they are more vulnerable or if the intensity of the hazard itself is greater too
In a similar way to the Degg model, increases in the magnitude of the hazard will increase the risk of a disaster. Equally, if the population becomes more vulnerable, the risk and intensity also increases.
Factors which increase the risk of a hazard:
Size of the affected area
Duration it is experienced for
Level of intensity or magnitude
Speed of onset (how quickly it happens)
Time of day/season
Frequency
Its difficult to stop a hazard occurring, for example we can’t prevent an earthquake. This means that governments tend to look at reducing a country’s vulnerability level in order to better manage hazards
PAR model (1)
The Pressure and Release model (PAR) explains a hazards socio-economic context and the combination of conditions in which a disaster could emerge
It suggests that there are certain root causes of vulnerability that create dynamic pressures (stresses on a population) which in turn lead to unsafe conditions when a hazard occurs. All of these develop a picture of a country's vulnerability to a natural hazard.
It also shows that nature of the hazard itself has a large part to play in whether a disaster is declared
PAR model (2)
The pressure in the title of the model comes from the idea that there is increased stress from both causes of the disaster, the natural hazard itself, as well as a layer of vulnerability. When either becomes too much, a disaster happens. In order to release the pressure, either the nature of the hazard or the degree the vulnerability needs to be reduced
The PAR model highlights the importance of a country’s economic development to its risk of experiencing a disaster.
Many root causes for vulnerability are less likely to be a problem in developed countries
The World Risk Index measures the level of vulnerability and exposure to hazards in different countries. Its an index score based on four factors
Exposure to hazards
Susceptibility to the impact of hazards
The capacity to cope with the impacts of hazards
The capacity to adapt to the impacts of hazards
When compared with the income level, you can see a correlation between this and vulnerability
Inequality (1)
Inequality is the unequal distribution of monetary and physical resources
A country’s level of vulnerability and resilience to natural hazard events often reflects its levels of economic, political, cultural and social development
Countries with a low level of development and a low score in the Human Development Index are more vulnerable and have an increased risk of experiencing a disaster
Inequality (2)
Where there are limited public funds, authorities are more likely to spend finances on short term urgent problems rather than long term hazard mitigation strategies. These are often very expensive and may not be need for some time
Pre-existing issues within a developing country, such as drought, external debt or civil unrest, can increase the country’s vulnerability when a natural hazard occurs
Increased vulnerability and reduced resilience may be caused by inequalities in Education (1)
Populations with less access to education have a reduced chance of perceiving and understanding hazard risks
They may be unable to read leaflets and posters or lack access to public information systems, such as radio broadcasts, that advise them of safe practices. This means that when a natural hazard occurs, they are less likely to know how to react to the hazard and may make decisions which endanger their lives
Increased vulnerability and reduced resilience may be caused by inequalities in Education (2)
Populations with low levels of education may view the ideas of experts and scientists as suspicion. When a natural hazard occurs, they might ignore official advice that would make them less vulnerable
Increased vulnerability and reduced resilience may be caused by inequalities in Housing (1)
Populations living in informal settlements made from low-grade materials are at greater risks in a natural hazard event. These buildings might not follow building codes, so they are more likely to be unsafe. This means that homes and businesses are less likely to be able to withstand a hazard, putting lives and livelihoods at greater risk
Increased vulnerability and reduced resilience may be caused by inequalities in Housing (2)
After a natural disaster, populations from low-income groups do not always have the means to rebuild. People may still be living in substandard or temporary housing when the next natural hazard occurs
Lower-income groups are more likely to live in areas that have a higher level of exposure to hazards
Increased vulnerability and reduced resilience may be caused by inequalities in Health care (1)
Populations with poor access to health care are at greater risk of illness, disease and death after a natural hazard. This may be due to:
A limited number of healthcare facilities
Fewer trained medical personnel
A lack of medical materials or drugs
Populations with poor healthcare systems may not have hazard emergency response teams
Increased vulnerability and reduced resilience may be caused by inequalities in Health care (2)
Populations from lower income groups are also more likely to be undernourished or suffering from lower levels of immunity to disease before a natural hazard occurs, si they have increased vulnerability when that event happens
Increased vulnerability and reduced resilience may be caused by inequalities in Income (1)
Populations with a majority of people in lower income groups are more likely to suffer in a disaster as they may lack the means to protect themselves. E.g. they may not be able to afford simple items (such as those you would find in an emergency kit) that would keep them alive until help arrives
Increased vulnerability and reduced resilience may be caused by inequalities in Income (2)
In the aftermath of a natural disaster, people from lower income groups are unlikely to have savings that will allow them to rebuild their homes and lives. If workplaces are destroyed people from lower income groups are more likely to lose the ability to earn an income as they have no means of employment
The places or work of those in higher income brackets are more likely to have insurance measures in place that will protect the salaries of their employees
Governance:
the systems of control that run a region or country
At both local and national governance has a part to play in how communities are able to react to natural hazards
A key aspect of this governance is having mitigation measures (a way of being prepared for natural hazards) in place
E.g. widespread educational programs for citizens and operational systems (such as flood defences) to deal with different eventualities
At a more basic level, governance needs to ensure that it is meeting the needs of its citizens and giving them the means to make themselves less vulnerable
E.g. a healthy and literate population is better equipped to cope with a disaster
Government agencies are also responsible for a degree of environmental management that can reduce the likelihood of secondary hazards occurring
E.g. programmes that afforest bare slopes can be put in place to reduce the likelihood of landslides during and after an earthquake
Some countries have national disaster management agencies. These work in the immediate aftermath of a disaster to try and reduce secondary impacts and to support people most in need
E.g. in 2022, FEMA in the USA had an annual budget of over $29 billion, which it can use to aid regions once a states governor has declared a state of emergency
Local authorities are likely to have their own natural disaster action plan. This will be location specific, taking into account the particulars of a local population and the facilities available to it. If a natural disaster happens, it is local authorities who are best placed to coordinate emergency response teams and aid that may come in from other regions
Population density can influence a community's vulnerability and resilience (1)
In some urban areas, infrastructure systems such as a sewerage network may come under pressure in normal conditions. A natural disaster may cause part of the system to shut down, decreasing its overall capacity to cope even further
Rapid levels of urbanisation mean that more people live in informal settlements which are more vulnerable to hazards
Population density can influence a community's vulnerability and resilience (2)
Urban areas have greater access to food, shelter and medical interventions that can aid a populations disaster recovery
Urban areas often have larger and more vulnerable building structures which are likely to be damaged by the natural disaster
Isolation and accessibility can influence a community’s vulnerability and resilience (1)
Populations in rural or isolated areas are more vulnerable to natural disasters because it can be difficult for rescue operations teams to reach people in the immediate aftermath
Isolation and accessibility can influence a community’s vulnerability and resilience (2)
Roads and bridges are more likely to be poorly maintained in these areas. This means these populations can suffer for longer without aid and response teams
Isolated areas may also suffer from a lack of communication infrastructure, e.g. it may be difficult to summon help if there is no mobile phone services
Degree of urbanisation can influence a community’s vulnerability and resilience
Places with a higher population density are more vulnerable to natural disasters as they are more difficult to evacuate so it's more likely people will be left behind
In more densely populated areas, emergency services and facilities, such as hospitals and health clinics, are often under pressure due to the amount of people they need to cater for, This pressure increases after a natural disaster, as the need for medical facilities and emergency services is likely to increase
Trends in death (Social impacts)
When characteristics of tectonic hazards are comparable (e.g. same magnitude) it is clear that developing and emerging countries have higher losses of life than developed countries
For example the Haiti2010earthquake killed 300,000 while in the New Zealand2011 earthquake 181 died
Emerging countries (e.g. India and China) have rapidly growing cities, which increases risk due to denser populations and uncertainties over building codes and land use zoning. Corruption in government departments may also reduce the effectiveness of mitigation measures
Trends in costs (economic impact) (1)
When the characteristics of a tectonic hazard are comparable (e.g. same spatial extent), it is clear that developed countries have greater costs of damage than emerging countries
This is because the ‘richer’ countries have more expensive buildings, infrastructure and technology to be damaged and high insurance costs after a disaster
Trends in costs (economic impact) (2)
Developing countries may only have significant construction in urban areas, and if rural areas are affected by a hazard, costs will tend to be low.
For example, volcanic eruption in Montserrat (1995) caused about $120 million damage while Mt St Helens, USA (1980), caused $970 million
GDP per capita Montserrat 1990 $6,980 and USA 1980 was $12,575
Magnitude is the size and intensity of a natural hazard event. It is measured using a numerical score on a scale which is often based on scientific measurements from seismic instruments
This means that there are inherentdisadvantages with using these scales
They can oversimplify the complexity and size of the hazard
Measuring a hazard based on its impact can be unfair, as a country’s economicdevelopment level has a large role to play in this