TECTONICS EQ2 Flashcards
Why do some tectonic hazards develop into disasters? (27 cards)
What is vulnerability?
How susceptible an area or population is to damage from a particular hazard event
-can be affected by:
*level of development
*population density
* size of hazard
*preparation and planning
What makes a hazard become a disaster?
The UN defines a disaster as having:
-10 or more deaths
-100 or more affected
- Declaration of state emergency
-Request for international assistance
What is the hazard risk equation?
The greater the vulnerability, the lower the capacity to cope, the greater the risk to the population, environment and economy
The greater the hazard magnitude and the lower the capacity to cope, the greater the risk of disaster.
Risk = Hazard x Vulnerability /capacity to cope
What is the hazard risk equation useful for?
allows a judgment to be made regarding an area’s resilience
can help to explain why hazards have such different impacts, but are similar in magnitude
What is a hazard?
A perceived natural event that has the potential to threaten both life and property
What is a disaster?
The realisation of a hazard, when it causes a significant impact on a vulnerable population
What is vulnerability?
high risk combined with an inability of individuals and communities to cope
What is the threshold for resilience?
The point at which a community can respond and recover from a disaster
What is the Degg model?
a Venn diagram combining factors of the hazard with factors of vulnerable communities and how they overlap to influence disaster risk
CASE STUDY: HAITI 2010
Vulnerability:
-the poorest country in the western hemisphere
-low-income country (lots of slums increase vulnerability
-unemployment as high as 90%
-70% live on less than $2 a day
Earthquake
-depth of 13km
-magnitude 7
-MMI level 9
-65km long fault
52 aftershocks
230,000 deaths (debated of up to 300,000
CASE STUDY: SICHUAN 2008
-87,150 dead or missing
- 4.8 million left homeless
-7.9 magnitude, largest earthquake to hit China since 1950
-$137.5 billion spent on rebuilding
-1.7 thousand km epicentre to Shanghai, where tremors were felt
-19km death
-The 2nd most costly earthquake recorded
Vulnerability:
-rapid urbanisation with poor building codes
-not built to withstand strong earthquakes
CASE STUDY: TOKOHU 2011
-magnitude 9 earthquake
- epicentre 43 miles from tokohu
- depth 20 miles
highly active earthquake zone
-caused a 40m high tsunami
-power station damaged, 7 reactors melted down
-most costly natural disaster in history
-aging population, 56% of deaths were over 65
- transport disrupted
-schools full of children destroyed by the tsunami
-16,000 deaths
CASE STUDY: INDIAN OCEAN 2004
-9.3 magnitude, the third biggest ever recorded
-affected Indonesia, Thailand and Malaysia
-220,000 deaths
-Some waves were 30ft high
-national holiday, lots of tourists
-no warning
Why don’t vulnerable communities relocate?
-financial reasons: lack of alternatives
-Cultural or territorial reasons
-jobs + work, farming cost-benefit
-family
-ignorance of risk
-fatalism
CASE STUDY: NEVADO DEL RUIZ 1985
-The most destructive eruption in history
-caused the largest lahar ever recorded
-23,000 fatalities
-Storm masked the summit, so residents were unaware of the pyroclastic eruption
-Amero town did not evacuate as they thought the eruption was over, and they did not predict the lahar
- Three-quarters of the town were killed
- VEI 3
CASE STUDY: ICELAND 2010
-created a 500m fissure
-An eruption happened beneath an ice sheet
- dissolved gases in magma + steam caused a large volcanic column of ash
-The eruption was predicted, and the surrounding areas had been evacuated
-The infrastructure was damaged
-Agriculture was damaged
-European airspace was at a standstill, costing billions of euros
CASE STUDY: MONTSERRAT 1995-97
- dormant for 300 years on a small Caribbean island
- became awake and active for 5 years
-Pyroclastic flows devastated the island
-The population of the island were evacuated in 1995
-19 people were killed (the majority farmers)
-Volcanic eruptions and lahars have destroyed large areas of Montserrat
-5000 people were living in a temporary shelter - The tourist and rice industries collapsed
-Unemployment rose to 50%
-VEI 3/4
CASE STUDY: PINATUBO 1991
-19km ash column
-Sisemic activity became intense
-Gas-charged magma caused the explosion
-huge pyroclastic flows, volcanic ash and pumice
-The summit of the volcano collapsed
-847 were killed
-300 from collapsing roofs
-100 from lahars and more from disease
-650,000 job losses
-$700 million in damages
-1.2 million lost their homes
-75,000 evacuated due to accurate predictions
-VEI 6
What is the Pressure and Release Model? (PAR)
-Root causes (eg. Poor governance is causing poor administration
-Dynamic pressures (eg, lack of building code reinforcement)
-Unsafe conditions (eg, poorly constructed buildings)
What are the links between Development and Disaster risk
-Disasters can limit, slow down or stop development, as the economy, infrastructure and population are damaged
-Development can cause increased disaster risk, as there are densely populated urban areas, and quickly built, poorly resistant buildings are made
-Development can reduce disaster risk, as more stable economies may have better buildings and more money to prevent and respond to disasters
-Disasters can create development opportunities, as aid work can improve the economy and job opportunities are more prevalent due to rebuilding.
What are the links between Inequality and Vulnerability?
- Higher inequality makes the population more vulnerable
-people are more vulnerable and less resilient if they lack access to: education, housing, healthcare and income - The Human Development Index (HDI) measures levels of development.
Low HDI involves lower education levels, poor quality housing and a lack of access to healthcare.
What are links between Governance and Vulnerability?
-Areas with good governance are more able to cope with hazard events and will have a faster recovery
- Areas with weak governance lead to increased vulnerability and impacts on the area’s ability to cope with a hazard event
-Poor governance impacts on the ability of the government to plan for hazards, educate on hazards, predict events and prepare for events
-Poor governance can also lead to corruption
What are the links between Geographical factors and Vulnerability?
-high population density makes evacuation difficult, and makes building collapse more frequent and damaging
- accessibility and isolation; isolated areas are harder to reach with aid, it’s harder to communicate with the population, infrastructure is poorer, and there are fewer facilities like medical assistance
-urbanisation; higher concentration of people and buildings, poorly constructed housing on slopes is particularly vulnerable
What is a hazard profile?
A diagram that shows the main characteristics of different types of tectonic hazards. It could be developed for a single hazard or include multiple hazards for comparison
-They help to develop disaster plans to prepare for future disasters and may focus on early warning systems
-Ongoing eruption hazard profiles may allow for focus on evacuation plans
