1.4A - Defiinitions

Definition of a natural hazard and a disaster, the importance of vulnerability and a community's threshold for resilience, the hazard risk equation. 

A natural hazard is a natural events that has the potential to harm people and their property. 
A disaster is the realisation of the hazard, i.e. harm has occurred. 
  • UN defines it as 'a serious disruption of the functioning of a community or a society involving widespread human, material, economic or environmental losses and impacts, which exceeds the ability of the affected community or society to cope using its own resources. 
  • Some large insurers define it as economic losses of over $1.5 million

By definition, disasters have to involve people and they occur at the intersection of people and hazards as shown by the Degg Model:
This shows the intersection between a hazardous natural event, such as an earthquake, hurricane or landslide and a vulnerable population which experiences human and/or economic loss, to create a disaster.

(Also called Degg's model)
A threshold level is often used to determine whether the impact of an event is large enough to be considered a disaster, such as:
  • 10 or more deaths
  • 100 or more people affected
  • US $1 million in economic losses

The relationship between risks, hazards and people is complex, due to:
  • unpredictability of hazard's timing and magnitude, catching people out
  • lack of alternatives - people staying due to a lack of options (work, lack of space, skills or knowledge)
  • dynamic hazards - threats change over time and can be affected by human influence
  • cost-benefit (OCR GCSE science, anyone?)
  • 'Russian roulette reaction' -  fatalism, acceptance of risks whatever you do 
​Risks can be understood by perception, and the point when a population or community chooses to adjust - varies by type of hazard and attitudes of decision makers. 
​​The relationship between hazards and disasters can be understood using the hazard risk equation. The risk of disaster rises if the hazard magnitude rises (e.g. VEI 6 eruption compared with a VEI 3). If vulnerability rises (poverty, lack of preparedness, lack of awareness of potential hazards,) so does risk;

risk = (hazard x vulnerability)/capacity to cope

Resilience
Some communities have a high capacity to cope and a high resilience. This means they can reduce the chances of disaster occurring because:
  • they have emergency evacuation, rescue and relief systems in place
  • they react by helping each other, to reduce numbers affected
  • hazard-resistant design or land-use planning have reduced the numbers at risk
For these communities the threshold for disaster will be higher than for ones with low coping capacity. 

Resilience is the ability of a community to cope with a hazard; some communities are better prepared than others so a hazard is less likely to become a disaster. It also includes the ability to return to normal following a disaster. 

According to the UNISDR the resilience of a community in respect to potential hazard events is determined by the degree to which the community has the necessary resources and is capable of organising itself both prior to and during times of need.  

Weird stuff to do with ageing
Age affects resilience as children and old people suffer more. Around 66% of those over 60 live in less-developed regions, expected to rise to 79% by 2050. 
The Disaster Risk and Age Index, compiled by the UNISDR highlights the trends of ageing populations and the acceleration of risk in a world that is increasingly exposed to a range of hazard types. It signals how age should be an important factor in understanding vulnerability and the coping capacity of older generations. 


​Let's Compare Japan and Myanmar!

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Myanmar
Japan
Hazard and exposure score
Significantly high natural hazard component due to the potential for tsunami and earthquakes (and floods and storms)
A range of natural hazards and is highly exposed. 
Vulnerability
Moderate risk though a relatively low score - few shocks in recent years. 
Vulnerability is high compared to other wealthy nations due to the ageing population, but is still low risk. 
Coping capacity
Poor coping capacity; low level of internet/mobile phone access for older people; poor education
Coping capacity is good, the elderly tend to be educated, have high internet connectivity, effective government and low gender inequality. lol. 
​Overall risk (UNISDR thing)
Myanmar is ranked 7th out of 190 nations, meaning disaster risk to elderly citizens is very high. 
Although Japan is highly exposed it's ranked 133rd out of 190 due to strong coping capacity and lower levels of vulnerability. 
(However older people in Japan still relatively vulnerable - 2011 tsunami killed 15,000 and 9500 injured or missing. 56% of those who died aged 65+, although they comprised 23% of the population in the affected area.