50 terms

Hazards and disasters - risk assessment and response

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Natural hazard
A natural process or event that has the potential to cause loss of life or injury or damage to property.
Disaster
A major hazard event that causes widespread disruption to a community or region that the affected community is unable to deal with adequately without outside help.
Magnitude
This is the strength of a hazard. Most hazards are measured on a scale e.g. the Richter scale.
Frequency
The return interval of hazards of certain sizes. For example earthquakes with a magnitude of over 8.0 happen on average once a year.
Speed of onset
The time difference between the start of a hazard event and its peak intensity.
Spatial concentration
Where hazards are located or centred. For example earthquakes tend to be focused along plate boundaries, whereas tropical storms tend to be located in coastal areas in the tropics.
Hazard
A threat (whether natural or human) that has the potential to cause loss of life, injury, property damage, socio-economic disruption or environmental degradation.
Hurricane Katrina 2005 (Category 5)
Hurricane in an MEDC.
Hazard event
The occurrence (realization) of a hazard, the effects of which change demographic, economic and/or environmental conditions.
Vulnerability
The susceptibility of a community to a hazard or to the impacts of a hazard event.
Risk
The probability of a hazard event causing harmful consequences(expected losses in terms of deaths, injuries, property damage, economy and environment).
Hurricane Katrina effects
Fatalities 1,800. 800,000 homeless, damage $108 billion (costliest in the USA).
Hazard event
The occurrence (realization) of a hazard, the effects of which change demographic, economic and/or environmental conditions.
One area with a lot of earthquakes in the basin of the Pacific Ocean.
One area with a lot of earthquakes in the Atlantic Ocean.
Common hurricane/typhoon/cyclone paths.
L'Aquila earthquake 2009
Earthquake in an MEDC (Abruzzo, Italy).
L'Aquila earthquake effects.
Casualties: 308 dead, 1,500 injured, 65,000+ homeless, 6 scientists imprisoned.
The Intertropical Convergence Zone (ITCZ) and its relevance for droughts (What goes up must come down).
The rainshadow effect (causing droughts).
Shanty settlements
Areas of 'homemade' housing with scavenged materials. Are vulnerable to hazards as they lack necessities such as hygiene, water, drainage, fire services and telecommunications.They are also built in high-risk locations such as steep slopes or river banks.
Cyclone Nargis 2008 (Category 4)
Cyclone in an LEDC (Myanmar)
Measures hurricane strength.
The Saffir-Simpson Hurricane Wind Scale.
Affected area of Cyclone Nargis.
India, Bangladesh, Sri Lanka and Myanmar.
Duration of Cyclone Nargis.
April 27, 2008 - May 7, 2008
Effects of Cyclone Nargis.
Fatalities: Nearly 140,000. 7 townships lost 95% of their homes.
Damage US$ 10 billion.
Factors making Cyclone Nargis (one of Asia's deadliest storms) victims vulnerable.
Low-lying land on a delta, set off a storm surge that reached 40 km inland, densely populated, affected Burma's rice bowl.
Cyclone Yasi, 2011 (Category 4)
Man-made Cyclone in an MEDC (mainly Queensland, Australia)
Effects of Cyclone Yasi
Fatalities: 1 indirect (due to successful evacuation - unlike Hurricane Katrina). Stronger winds than Cyclone Nargis.
Chernobyl, 1986 (level 7 event).
Human-induced hazard event.
Location of Chernobyl
Pripyat, (formerly part of the Soviet Union, now Ukraine) with 50,000 inhabitants, farm land, woodland, Chernobyl (12,000).
Effects of Chernobyl
31 people died during the event, 50 emergency workers died soon after the accident from acute radiation syndrome, 500,000 liquidators (Russian for "clean-up workers" are dead from or suffering from radiation sickness, thyroid cancer in children, increase in psychological problems among the affected population due to exaggerated fears about the effects of radiation (Life expectancy in Belarus for men is now 10 years lower than in Sri Lanka, one of the 20 poorest countries in the world), deformities and long-term mutations among children. 1.3 million people still live on contanimated land. Pripyat will be uninhabitable for at least 20,000 years.
Measures the severity of a nuclear accident.
International Nuclear Event Scale
Cause of the Chernobyl disaster
The accident occurred during an experiment scheduled to test a potential safety emergency core cooling feature. Reactor 4 suffered a catastrophic power increase, leading to explosions in its core. This dispersed large quantities of radioactive fuel and core materials into the atmosphere.
The areal extent of the Chernobyl fallout
Due to the weather conditions, 60% of the fallout landed in Belarus. 350,00 people were evacuated and resettled from the most severely contaminated areas of Belarus, Russia, and Ukraine. Also places like Norway and Sweden, Scotland, Wales and some places in the Alps were affected.
Quantifies the energy that is released in an earthquake.
The Richter Scale (which has been substituted by Moment Magnitude Scale in many countries).
Measures the intensity/effects of an earthquake.
The Mercalli intensity scale (today the Modified Mercalli scale).
Haiti earthquake, 2010 (magnitude 7).
Earthquake in an LEDC.
Location of the Haiti earthquake.
Port-au-Prince, Haiti's capital, and the Dominican Republic.
Factors that made the Haitians vulnerable.
Acute poverty, a youthful population, rapid population growth (Port-au-Prince grows by 5% annually), unplanned urbanization, shanty towns, densely built housing, not earthquake resistant houses, shallow earthquake, epicentre near, no broad-based economic development.
The causes of arid conditions.
Permanently arid conditions: The subtropical high-pressure belt (20-30 degrees N), continentality, cold offshore currents, rain-shadow effects,
Short-term droughts: El Nino and La Nina.
The Horn of Africa Drought, 2011-2012.
Drought in LEDCs (Ethiopia, Kenya, Somalia and Djibouti)
The effects of the Haiti earthquake.
230,000 killed, 250,000 injured, 1 million homeless (only 63 killed in a similar earthquake in California in 1989 - mainly due to better buildings).
The Murray-Darling Basin drought, 12 years till 2010.
Drought in an MEDC (south-east Australia - the country's breadbasket).
Effects of the Horn of Africa drought.
Worst drought in 60 years, with more than 12 million people urgently needing food aid. Malnutrition, increased livestock mortality, severe food insecurity, refugees in camps.
Adjustment strategies for hazards (used before and after).
Modify the hazard (like cloud seeding) or changing the loss potential (through building design, warning systems, land-use planning, drought-resistant crops etc.)
Adjustments to the loss.
Spreading losses (insurance, aid), planning for loss or simply bearing the loss.
Response strategies to hazards.
Short-term rescue, shelter and aid, medium-term restoration of infrastructure and long-term reconstruction and rehabilitation.
How estimates are made for the probability of a major hazard event.
Identification of trends and patterns, based on previous events. Return intervals for hurricanes, gap theory for earthquakes, historical records, location (on plate boundaries, in the tropics etc.)
How estimates are made for the likely impact of a major hazard event.
Spatial analysis of the vulnerability of the population (lives and property), the use of GIS (Geographic Information Systems involve combinations of information, grouped by layers) to identify areas where housing types are less resilient, where families cannot afford insurance or have no financial reserves to recover quickly).