Tectonic Hazards EQ2 - Tectonic disasters Flashcards
What is a natural hazard?
A perceived nautral/geophysical event that has the potential to threaten both life and property
What is a natural disaster?
The realisation of a hazard, when it causes significant impact on a vulnerable population
What is Degg’s model?
Venn diagram stating that a disaster is the intersection of a hazardous geophysical event, and a vulnerable population
Why is vulnerability important?
Vulnerability is directly linked to resilience, and a region’s capacity to cope with tectonic hazards. More vulnerable populations are susceptible to worse impacts from tectonic hazards.
What is risk?
The probability of a hazard occurring that leads to the loss of lives and/or livelihood
What is resilience?
The ability of a system, community or society exposed to hazards to resist, absorb and recover from the effects of a hazard
What is vulnerability?
The geographical conditions that increases the susceptibility of a community to a hazard or to the impact of a hazard event.
What is the resilience of a community determined by?
The degree to which the community has the necessary resources and is capable of organising itself both prior to and in times of need
What is the hazard-risk equation?
risk = hazard x vulnerability/manageability)
What factors explain the complex relationship between risks, hazards and people?
- unpredictability of hazards
- lack of alternatives
- dynamic hazards
- cost benefit
- ‘Russian roulette’ reaction
What is the Disaster and Risk age index, what does it show?
Index which 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.
What is the basis for the Pressure and Release model?
A disaster is the intersection of processes generating vulnerability on one side and the natural hazard event on the other
What 3 factors are involved in the progression of vulnerability from the PAR model?
- root causes
- dynamic pressures
- unsafe conditions
What are some examples of root causes, dynamic pressures and unsafe conditions?
Root causes - limited access to resources. Ideologies
Dynamic pressures - lack of training, local investment. Rapid changes (urbanisation, deforestation)
Unsafe conditions - fragile physical environment, vulnerable society
What are the social impacts of tectonic hazards?
- death/injury
- destruction of homes
- displacement, people made homeless
What are the economic impacts of tectonic hazards?
- buildings/infrastructure damage
- economic losses
- growth of economy prevented
Why are the impacts of tectonic hazards often greater in less developed countries?
Less developed countries = poorly built infrastructure, poor healthcare, lack of resources to properly protect property, overpopulation, poverty
This creates a vulnerable society with a lack of ability to be resilient to tectonic hazards
Why are the impacts of earthquakes generally greater than those of volcanoes?
- concentration of volcanoes in narrow belts (less than 1% of population exposed to volcanic activity, whereas 5% at risk from earthquakes)
- volcanic eruptions have a slower speed of onset and greater spatial predictability
- earthquakes cannot be predicted (no diagnostic precursor), there is greater opportunity for volcano mitigation
What are the different scales to measure earthquakes?
Richter
Moment Magnitude scale
Mercalli
How does the Richter scale measure earthquakes?
Scale = 0-9
Measurement of amplitude of waves produced by an earthquake. It is an absolute scale.
How does the Mercalli Scale measure earthquakes?
Scale = I-XII
Measures the experienced impacts of an earthquake. It is a relative scale
How does the Moment Magnitude Scale measure earthquakes?
Scale = 0-9
Measurement based on ‘seismic moment’ of the earthquake.
What scale is used to measure volcanic eruptions?
Volcanic Explosivity Index
How does the VEI measure volcanic eruptions?
Scale = 0-8
Relative measure of the explosiveness of a volcanic eruption (includes qualititive observations)
