Tectonics - Topic 3 Flashcards
Disaster Risk Management (82 cards)
What are tectonic disaster risks?
- The potential damage to properties, injuries and loss of lives from a disaster, in a given period of time.
- It is determined as a product of the interaction between hazard, vulnerability and exposure to earthquakes and volcanic eruptions
What is disaster risk management?
Disaster risk management refers to the plans and action that are in place to:
- Prevent disaster risk before the occurrences of tectonic hazards
- Reduce disaster risks as tectonic hazards occur
- Manage disaster risks after the occurences of tectonic hazards
Disaster risk management strengthens resilence as it enables communities and countries to resist, adapt and recover from the impacts of tectonic hazards in a timely manner
How do you prevent disaster risks before the occurrences of tectonic hazards? Provide an example with your explanation
- Strategies include designing hazard-resistant building to ensure structures can withstand hazards and do not collapse easily, hence preventing disaster risks
Example:
* Taipei 101 is a skyscraper built in an earthquake-prone zone
* It has a weighted damper near the top of the building to balance out ground shaking from the earthquakes. This reduces the shaking from earthquakes. This reduces the sway of the building during an earthquake and therfore the threat of the building collapsing
How do you reduce disaster risks as tectonic hazards occur?
- Strategies include tsunami and earthquake early monitoring and warning systems . This enables timely evacuation and reduces potential loss of lives
How do you manage disaster risks after the occurrences of tectonic hazards?
- Strategies include insurance coverage, which offers financials payouts to rebuild when properties are damaged or destroyed
- This brings about quicker recovery from the impacts of a tectonic hazards
How do disaster risks and losses hinder development?
Disaster risks can bring serious environment, social and economic consequences, affecting both indivduals and countries
These consequences may hinder development of countries
* When countries have to channel money to rebuilding after a tectonic hazard, their development may be slowed down as less money can be invested in other areas such as infrastructure and education
* These costs are especially detrimental to developing countries where the need for development is the highest, abd where funds may be lacking
* Poverty reduction progress may be affected aks people are driven into poverty and their standards of living drop when they lose their source of income and homes
Examples:
1. For instance, farmers may be unable tp irrigate due to the contamination of water sources, and fisherman, who lose their bost to tsunamis are note able to fish
2. Schools and healthcare facilities may be damaged. disrupting social services to disadvantaged communities, resutling in a drop of their standard of living
- The 2004 Indian Ocean tsunami pushed the proportion of people lviing below the poverty line in Aceh, Indonesia, from 30 to 50%. Many loss their homes, jobs and sources of incomes, hindering Aceh’s development
Countries’ economic growth may also be slowed down, affecting their development progress:
* For instance their entire tourism may be severly affected due to damage to infrastructure, facilities and amenties, resutling loss of revenue to people and the government
How does disaster risks result in environmental consequences?
- Tectonic hazards such as landslides caused by volcanic eruptions can bury huge areas of forests and wetlands , destroying entire ecosystems and causing biodiversity loss
- The debris from landslides pollutes rivers, killing aquatic life
- The debris may block rivers, causing floods that can damage nearby ecosystems
How does disaster risks result in social consequences?
- Tectonic hazards such as tsunamis can result in injuries and loss of lives as people drown and get hit by fast-moivngd ebris carried by the waves
- People may become destroyed. They may be fored to live in temporary housing which lacks proper sanitation, resuytling in poor standards of living
- The sea water brought inland by tsunami may contiminate wellls and other sources of drinking water, causing water pollution. This may result in the spread of diseases such as cholera
- Individuals may suffer from psychologcal trauma from the loss of their homes or love ones. In addition, the constant threat of losing their libves and being physically harmed while living in these areas can affect their mental well-being
How does disaster risks result in economic consequences?
- Tectonic hazards can cause the destruction of homes are properties
- Individuals may suffer financially as it is costly to repair or rebuild their damaged homes
- Business owners can lose incomes caused by damage to their properties
- Governments need to spend money to repair and rebuild because of the damage from tectonic hazards
Why is it important to reduce disaster risks?
Reducing disaster risks is important for disaster-prone developing countries because:
* The social, economic and environmental consequences can be very severe, and may hinder development
* Developing countries are foten disproportionately affected by tectonic hazards because they often lack the capacity (e.g. technological know-how and resources) to adequately prevent, reduce and manage disaster risks
Example:
* During the Mw 7.0 Haiti earthquake in 2010, most of the city was destroyed. This is because they lacked the finances to invest in earthquake-resistant buildings, leading to many collapsed buildings and over 220,000 deaths.
* In comparison, the Mw 9.0 Tohoku, Japan earthquake and tsunami in 2011 had a lower death toll (about 19,000 deaths) even though it was higher in magnitude. As a developed country, Japan had more earthquake-resistant buildings. While the tsunami led to devastating damage, Japan was also in a better position to recover due to their available resources.
However, there are developing countries which do manage to reduce their disaster risk through investment and planning.
* Reducing disaster risk is a cost-effective investment in preventing future losses, and therefore contributes to sustainable development.
* The additional investments to reduce disaster risks are often small compared to the costs incurred from disasters.
* With less losses, the money to rebuild will be minimised, and development gains achieved will not be lost, thereby contributing to sustainable development.
Example:
* The Mw 8.8 Chile earthquake in 2010 resulted in lesser building damage and a lower casualty count of about 500 when compared to the 2010 Haiti earthquake which had a lower magnitude. One reason was due to Chile’s modern earthquake-resistant buildings.
Define “chemical composition of magma”
Chemical make-up of magma. Different types of magam may contain different substances (e.g. silica or iron) in different amounts
What is the “distance from epicentre”
The space between where earthquakes begin and where earthquakes are experienced. Seismic enegry decreases as it radiates outwards from the epicentre
Define “exposure”
Refers to the situation of people and their belongings located in hazard-prone areas
Define “Nature of hazard”
Characteristics of the hazard, such as its duration
Define “population density”
The number of people in a unit area of land. When population density is high, more people will be at risk from an earthquake
Define “prevailing wind”
Wind blpwing from the dominant wind direction
Define “vulnerable conditions”
The conditions deteermined by physical, social, economci and environmental factors, which increase the susceptinility of people and their belongings to the impacts of hazards
What factors affect the extent of tectonic disaster risks across places?
The extent of tectonic disaster risks experienced in a place is determined by the interactions between tectonic hazards, and vulnerability and exposure to earthquakes and volcanic eruptions:
Factors influencing disaster risks include:
* Nature of hazard
* Vulnerable conditions
* Exposure
The greater the vulnerabilityh and exposure to tectonic hazards, t,he greater the potential loss of human lives and damage to properties
Depebnding on the level of vulnerability and exposure to tectonic hazarfs, each place will experience tectonic disaster risks to different extents
What are the factors affecting the extent of tectonic disaster risks for volcanic eruptions?
For volcanic eruptions:
Nature of hazard:
* Chemical composition of magma
Vulnerable conditions
What are the factors affecting the extent of tectonic disaster risks for earthquakes?
For earthquakes:
Nature of hazard:
* Duration of shaking
* Time of shaking
Vulnerable conditions:
* Quality of building design and construction
* Soil and rock properities
Exposure:
* Population density
* Distance from epicentre
Give an example where disaster risks caused by earthquakes be influenced by vulnerable conditions, more specifically on the quality of building design and construction
Example:
* Druing the 2010 Mw 7.0 earthquake that occurred in Port-au-Prince Haiit, many buildings and infrastructure collapsed
* The buildings in Haiti are made up of poor-quality materials, and the concrete pillars holding up the buuildings are poorly reinforrced
* More than 80% of all buildings near the epicentre were destroyed during the earthquake, contributing to more than 220,000 lives lost
How can disaster risks cause. by earthquakes be influenced by the nature of the hazard, more specifically on the time of shaking
The time of day influences the activitie carried out by people and how they respond when the earthqauke strikes.
* If people are asleep at night, they will be less alert and are unable to evacuate quickly
* On the other hand, as people are at work or school during the day, they are more alert and able to evacuate quickly
* Hence, they will less likely be trapped, leading to less injuries and loss of lives
Example:
* The 1995 Kobe, Japan earthquake (Mw 6.9) occurred in the early morning at around 6am. As many people were asleep, they were trapped at home, leading to more than 6,000 lives lost.
How can disaster risks caused by earthquakes be influenced by the nature of the hazard, more specifically on the duration of shaking
1. Duration of shaking
The length of time of ground shaking can influence the extent of shaking can influence the extent of disaster risks
The longer the duration of ground shaking, the more damaging an earthquake will be.
- Structures such as buildings and bridges subjected to a long period of stress are more likely to collapse
- People will more likely be trapped in collapsed infrastructure, leading to more injuries and loss of lives
Example:
* The 2011 Tohaku, Japan earthquake (Mw 9.0) lasted for 6 minutes, causing massive damage to buildings
How can disaster risks caused by earthquakes be influenced by vulnerable conditions, more specifically on the quality of building design and construction
The quality of building design and constructiton plays a huge part in determing the extent of disaster risks
In general, earthquakes do not kill people, buildings and their contents do.
The poorer the quality of building deisgnn and construction, the more vulnerable the buildings are collapsing, leading to more trapped people, injuries and loss of lives.
Hence, the disaster risks are higher.
Buildings and infrastructure are more vulnerable to collapsing when they:
* Are poorly built with low quality materials such as zinc sheets or materials that are rigid that are unable to withstand the shaking
* Do not follow building codes set by authorities
* Lack earthqauke-resistant features such as reinforced steel walls