Classification of tectonic events Flashcards
Disaster definition
A serious disruption of the functioning of a community or society involving human, material, economic and environmental losses which exceeds the ability of the affected community or society to cope using its own resources
Risk calculation
R = Hazard (H) x Vulnerability (V) / Capacity to cope (C)
A place may be at high risk because…
Their capacity to cope is low.
- They are quite vulnerable.
- The hazard is large/ high intensity.
Haiti 2010 earthquake
Degg’s model
A disaster will only occur when a vulnerable population (one that will be significantly disrupted and damaged) is exposed to a hazard. Degg’s model is a good representation of this concept. If the population is not vulnerable, the hazard will not have a significant effect, thus the event will not be disastrous
Park’s model stages
1- Relief
2- Rehabilitation
3- Reconstruction
Pressure and release model (PAR)
used to analyse factors which cause a population to be vulnerable to a hazard. On one side of the model we have the natural hazard itself, and on the other side different factors and processes which increase a population’s vulnerability to the hazard. This vulnerability is often rooted in social processes. These are dynamic and ever changing and are often unrelated to the hazard itself e.g. poverty, poor governance
Tectonic hazard profile characteristics
▪ Frequency – How often it happens
▪ Magnitude – How extensive an area the event could affect
▪ Duration – How long the event lasts
▪ Speed of onset – How much warning time before event occurs
▪ Fatalities - Number of deaths caused
▪ Economic Loss - Value of assets damaged, lack of industry or economic productivity, insurance policies.
▪ Spatial Predictability - The predictability of where would be affected
Questions to evaluate the effectiveness of a tectonic hazard model
● Can they be applied to every hazard? Are some hazards more complicated and require a more complex model? It may be useful to apply each of your case studies to these models and see how they compare.
● Does the model take any aspects of hazards into account such as level of development?
● Is there any timeframe? Do the models accurately lay out the time taken for a full response and how this changes due to aspects of the hazard such as intensity?
● Could the model be less vague/ include more steps that can be applied to all
hazards?
Volcanic Explosivity Index (VEI)
● Measures the relative explosiveness of a volcanic eruption.
● Based on the height of ejected material and duration of eruption.
● Scale goes from 0-8 and is logarithmic (increase of 1 on the scale indicated a 10 times more powerful eruption)
The Modified Mercalli scale
● Measures the destructiveness of an earthquake.
● It is a relative scale as people would feel different amounts of shaking in different places.
● It subjective as based on if people wake up, if furniture moves, how much damaged structures receive.
● The scale varies from I to XII
I = Generally not felt by detected on seismographs XII = Nearly total destruction
● It doesn’t consider economic, social and environmental impacts.
Moment magnitude scale
● Measures the amount of energy released in earthquake. ● Scale from 0-9.
● It’s a simple measure, so
environmental or social impacts must be inferred
Richter scale
● Measures the amplitude of the waves produces during an earthquake
● Most widely used scale, as it’s
absolute
● Must infer social or environmental impacts, which can be misleading. The highest Richter scale earthquake readings won’t necessarily be the worst disasters.
● Like the VEI its scale is logarithmic