Tectonics EQ2 Flashcards
What is a disaster
When a hazard has a significant impact on people i.e. consequence of hazard
If damage caused by hazard exceeds threshold level, disaster has happened
Describe risk
The probability of a hazard happening and creating a loss of lives/livelihoods
Describe vulnerability
Risk of exposure to hazards combined with an inability to cope with them
Describe resilience
Degree to which a population or environment can absorb a hazardous event and stay organised and functioning i.e. population or environments ability to cope with stress and recover
What is the risk equation
Risk = hazard x vulnerability/capacity to cope
What features increase a populations ability to cope
Having emergency evacuation, rescue and relief systems in place
Helping each other reduce the numbers affected
Having a hazard-resistant design or land-use planning to reduce numbers at risk
What does the PAR model show
Connections between the nature of a hazard and its wider context
What are the main features of the PAR model
Says risk is a function of vulnerability and nature of hazard
Socio-economic context is important e.g. income levels, education levels and political system
Nature of hazard is key i.e. whether it’s a volcano, earthquake, storm or landslide
Everything is dynamic, so safety of people is difficult to manage
What social impacts do hazards cause
Deaths, injury and wider health impacts including psychological ones
What economic impacts do hazards cause
Loss of property, businesses, infrastructure and opportunities
What environmental impacts do hazards cause
Damage or destruction of ecosystems
How do hazard impacts vary between countries
Difficult to compare impact between countries because:
Physical nature of events is different
Socio-economic characteristics are different
Economic costs in developed countries can be very large but less costly in developing
Deaths in developed countries usually low but can be high in other countries
Impacts of volcanic eruptions tend to be smaller than impacts of earthquakes and tsunamis
How is earthquake magnitude measured
Amount of energy released is measured by the Moment Magnitude Scale (MMS)
MMS goes from 1 to 10, greater number = greater magnitude
Scale is also logarithmic - increase of 1 unit of magnitude increases amount of shaking by 10 and amount of energy released by 30
How is earthquake damage measured
Using the Mercalli scale
Measured the intensity of shaking on a scale of 1 to 12
How is volcano magnitude measured
Using the Volcanic Explosivity Index (VEI)
VEI based on volume, duration and column height of eruptions
Explosivity is related to type of magma and type of plate boundary volcano is located on
Give examples of VEI
Effusive eruption of basaltic lavas with low VEI (0 to 3) normally happen on constructive boundaries
Explosive eruptions with high VEI (4 to 7) happen on destructive boundaries
What are hazard profiles used for
To compare the characteristics of tectonic hazards
What do hazard profiles show
Summarise the physical processes shared by all hazards so most at risk areas can be determined Show how different types of hazard vary in: Magnitude Speed of onset Areal extent Duration Frequency Spatial predictability
Which events present the highest risk
High magnitudes Low frequencies Rapid speed of onset Low spatial predictability Large areal extents These events happen mostly at subduction and collision zones
What impact does HDI and vulnerability have on an area
Locations with low HDI (<0.55) have a high vulnerability because:
Many people lack basics things e.g. having enough water and food, even in normal times
Lot of housing is informally constructed with no hazard resilience
Poor access to healthcare, so disease and illness common
Education levels lower so hazard perception and risk awareness are low
After disaster, government may not be able to provide social security or free healthcare for low-income groups
What impact does inequality of access have
Inequality of access to education, housing, healthcare and income are root causes of hazards because they influence vulnerability and resilience
Inequality seen in PAR model
HDI measures this inequality
How can government preparedness be done to reduce disaster vulnerability
Land-use planning and zoning to prevent house construction in dangerous areas
Environmental management to prevent factors such as deforestation making area more naturally dangerous
Effective monitoring systems
Preparedness by providing education and community awareness programmes
Having insurance
How does good governance reduce disaster vulnerability
If governance of country is good at meeting day to day needs of population, country = less vulnerable to disasters
Government should be meeting basic needs by providing sufficient food and water for its population
Should also be tackling corruption and making sure that aid money is not taken by officials
How does population affect vulnerability to natural disasters
Highly populated areas may be hard to evacuate because there are so many people
Isolated populations in places that are difficult to access may take a long time to reach
