Why do Some Tectonic Hazards Develop into Disasters? Flashcards
(21 cards)
What is a disaster?
A disaster is a serious disruption of the functioning of a community or society, resulting in human, material, economic, and environmental losses that exceed the ability of the affected community or society to cope using its own resources.
How is the risk of a natural hazard calculated?
The risk of a natural hazard is calculated using the following equation:
Risk (R) = Hazard (H) x Vulnerability (V) / Capacity to cope (C)
What factors affect the risk of a natural hazard?
A place may be at high risk if:
Capacity to cope is low.
The population is vulnerable.
The hazard is large or of high intensity.
What is Degg’s Model?
Degg’s Model demonstrates the relationship between hazards, vulnerable populations, and disasters. It suggests that disasters occur when a vulnerable population is exposed to a hazard. The model highlights that a disaster will not occur if the population is not vulnerable to the hazard.
The model includes three key elements:
Hazardous Event
Vulnerable Population
Disaster Outcome
How is a hazard or disaster classified?
There are several ways to classify a tectonic hazard, each with different measures and outcomes:
Volume of people affected: The International Disaster Database classifies a disaster as an event where more than 100 people are affected or more than 10 people die.
Economic cost: Includes the loss of jobs, cost of repairs, and economic productivity lost. The UN Sendai Framework aims to reduce economic losses due to disasters.
Comparison to previous events: Using prediction models or average statistics for a location to assess the severity. However, rare mega-disasters can skew averages, making it important to treat average statistics carefully.
What is the Park Model?
The Park Model is a graphical representation of human responses to hazards, showing the recovery steps and time frame after a hazard.
Stage 1 - Relief (hours to days):
Immediate local response (e.g., medical aid, search and rescue).
Immediate appeal for foreign aid begins.
Stage 2 - Rehabilitation (days to weeks):
Services begin to be restored (e.g., temporary shelters, hospitals).
Foreign aid is coordinated (e.g., peacekeeping forces).
Stage 3 - Reconstruction (weeks to years):
Area is restored to the same or better quality of life.
Infrastructure is rebuilt, and ecosystems and crops are restored.
Mitigation efforts for future events are implemented.
What is the Pressure and Release Model (PAR)?
The Pressure and Release Model (PAR) is used to analyze the factors that cause a population to be vulnerable to a hazard.
On one side, it addresses the natural hazard, and on the other side, it examines the factors that increase vulnerability.
These vulnerability factors are often social processes, such as poverty and poor governance, which are dynamic and ever-changing.
By reducing social factors that increase vulnerability, we can reduce the pressure people face, thereby reducing the effect of natural hazards.
What are the three sections of the progression of vulnerability in the PAR model?
Root Causes: Economic, demographic, and political processes that affect large populations or entire countries.
Dynamic Pressures: Local economic or political factors that affect a community or organization (e.g., rapid urbanization).
Unsafe Conditions: Physical conditions affecting individuals (e.g., unsafe buildings, low income, poor health).
What are the different types of vulnerability?
Physical Vulnerability: Individuals living in hazard-prone areas with little natural or mitigative protection.
Economic Vulnerability: People who risk losing employment, wealth, or assets during a hazard. MEDCs tend to be more economically vulnerable than LEDCs.
Social Vulnerability: Communities that cannot support their most vulnerable members, leaving them at risk from hazards.
Knowledge Vulnerability: Individuals who lack training, knowledge, or warnings about the risks of hazards or how to safely evacuate (e.g., fatalist beliefs).
Environmental Vulnerability: A community’s risk increases due to high population density in hazard-prone areas.
How do the components of the PAR model work together?
Factors contributing to a population’s vulnerability are interconnected:
Unsafe living conditions (e.g., lack of infrastructure, dangerous settlement locations).
Dynamic pressures (e.g., rapid urbanization, lack of training, poor communication).
Root causes (e.g., weak governance, mismanagement by industries, high reliance on vulnerable products).
For example, poor infrastructure might worsen the impact of a hazard, and this could be a result of rapid urbanization, which itself is caused by weak governance.
What are some common factors affecting a society’s vulnerability?
Root Causes:
Weak governance, mismanagement by industries, and heavy reliance on vulnerable products (e.g., agriculture near hazards).
Dynamic Pressures:
Lack of training/knowledge, rapid urbanization, poor government-local communication, and natural environmental factors.
Unsafe Living Conditions:
Lack of infrastructure (clean water, sewage removal), dangerous settlement locations (e.g., near nuclear stations or natural hazards), no warning systems, and degraded natural defenses (e.g., deforestation of mangroves).
Lack of basic services (health, education, police) can facilitate the spread of disease and fire.
What are the characteristics of a Tectonic Hazard Profile?
Frequency: How often the event occurs.
Magnitude: The extent of the area affected by the event.
Duration: How long the event lasts.
Speed of Onset: The amount of warning time before the event occurs.
Fatalities: The number of deaths caused by the event.
Economic Loss: The value of assets damaged, loss of industry or productivity, and the cost of insurance claims.
Spatial Predictability: The ability to predict where the event is likely to affect.
Why is it difficult to measure the full impact of a hazard profile?
Measuring the impact of multiple hazards or events with secondary hazards (e.g., tsunamis after earthquakes) is challenging, as the secondary hazards may cause more damage than the primary event itself.
What are hazard models used for?
Hazard models are used to understand, predict, and assess the potential impacts and responses to natural hazards.
They help guide decision-making and resource allocation during hazard events and recovery processes.
Why can hazard models be less effective?
The unpredictability of hazards makes it difficult for models to accurately represent human responses to hazards.
Factors like the complexity of hazards, local circumstances, and the dynamic nature of communities can cause variations in outcomes.
What are some key questions to ask when evaluating the effectiveness of hazard models?
Can the model be applied to every hazard?
Some hazards may require more complex models due to their unique characteristics.
It’s useful to compare models across different case studies to see how well they apply to various hazards.
Does the model account for the level of development?
The model’s effectiveness may be influenced by the development level of the affected region. More developed areas may have better preparedness and resources, while less developed areas might struggle with response.
Does the model consider timeframes?
The model should account for the time taken for a full response to a hazard, which can change based on factors like the intensity of the event.
It’s important to evaluate how quickly different stages (e.g., relief, rehabilitation, reconstruction) unfold in real-world situations.
Could the model be more specific or detailed?
The model may be too vague, with broad categories that do not apply to all hazards. More specific steps could improve its accuracy and usability across a wider range of events.
Does the model address current or future hazards?
Consider if the model adequately represents the types of hazards we face now and whether it needs modifications to account for climate change and its effects on the frequency and severity of hazards.
It’s important to question whether hazard models will remain relevant as the frequency of hazards increases or mitigation strategies become more challenging.
What is an example of how hazard models might need to evolve?
Climate change is expected to increase the frequency and intensity of many natural hazards (e.g., floods, storms). Models that were effective in the past may not account for these new realities, so they may need to be updated to remain relevant.
What is the Volcanic Explosivity Index (VEI)?
The VEI measures the relative explosiveness of a volcanic eruption.
It is based on the height of ejected material and the duration of the eruption.
The scale ranges from 0 to 8 and is logarithmic; an increase of 1 on the scale indicates a 10 times more powerful eruption.
What is the Modified Mercalli Scale?
The Modified Mercalli Scale measures the destructiveness of an earthquake.
It is a relative scale, meaning people in different locations may experience varying amounts of shaking.
The scale is subjective, based on observable effects such as:
Whether people are awakened
Movement of furniture
Damage to structures
Scale range:
I: Generally not felt, but detected on seismographs
XII: Nearly total destruction
It does not consider economic, social, or environmental impacts.
What is the Moment Magnitude Scale?
The Moment Magnitude Scale measures the amount of energy released by an earthquake.
The scale ranges from 9 to 9+.
It is a simple measure, and the social or environmental impacts must be inferred from the data.
What is the Richter Scale?
The Richter Scale measures the amplitude of the waves produced during an earthquake.
It is the most widely used scale for measuring earthquakes and is absolute.
Like the VEI, it is logarithmic, meaning each increase of 1 on the scale represents a tenfold increase in wave amplitude.
Social and environmental impacts must be inferred, which can sometimes be misleading as the highest Richter scale readings may not always correspond to the worst disasters.
