Hazard 4: Future Resilience and adaptation Flashcards
What has happened to the frequency of hazards?
- Hydro-meteorological hazards ( floods, storms, cyclones, droughts) have all become more common – possible link to climate change & deforestation.
- Frequency of tectonic hazards has remained static.
- Landslides have increased over time.
- The number of people affected by tectonic disasters has increased.
What are the key features and trends of earthquakes?
Key features of earthquakes ( since 1980):
- No. of disasters has been 15-40 per year.
- Deaths have been variable, with some large events in come years.
- Mega disasters in 2004 ( Bande Aceh Tsunami) & 2010 ( Haiti earthquake) resulted in huge deaths – over 200,000 each.
- Economic loses have increased – more to lose as affluence increases.
What are the key features and trends of volcanoes?
Key features of volcanoes ( since 1980):
- the number of disasters is lower than earthquakes, and deaths are much lower.
- Only 7 eruptions have killed more than 100 people.
- Wider impacts can be great as large scale evacuation is needed.
If you look back in history it appears volcanoes & earthquakes are occurring more frequently, they aren’t. It is just they are now better monitored and recorded.
What are the key features and trends of landslides?
Clearer increasing trend – probably due to increased extreme weather events ( many caused by climate change), as well as increasing population pressure & land use change.
What are the reasons for the varying impacts of disasters over time?
- HICs have seen a decrease in number of disaster related deaths due to improved preparation & prediction. LICs have experienced little change, as lack capital to make adjustments.
- Economic losses mainly in developed countries.
- It has been suggested than increased human activity has affected both the frequency & intensity of disasters e.g. Earthquakes can be triggered by human processes, such as mining & fracking e.g. UK.
- Earthquakes have caused an increasing number of deaths over time. This is largely due to the increasing number of people living in seismic areas which has increased 93% in 40yrs. Tsunamis affect large coastal areas in many regions.
- Predicted by 2050 – 3bn people with live in slums in dangerous locations.
What are the reasons for disaster trends and influences on trends since 1960?
What are future possibilities for lessening human vulnerability to geophysical hazards?
- Technology
- Land use zoning
- Preparedness
- Insurance
How can technology be used to lessening human vulnerability to geophysical hazards? And what are the benefits and issues?
Technology e.g. Smart phone apps related to advanced warning. Using GIS images to see create maps to show where movement was greatest.
Seismographs, strain meter, creep meter, magnetometer, tilt meter, radon gas…
Benefits: Warnings/evacuations can save lives.
Issues: Costly, mainly found in HICs/NEES. Possibility of cry wolf syndrome, property is still damaged.
How can land use zoning be used to lessening human vulnerability to geophysical hazards? And what are the benefits and issues?
Land use zoning:
- Prevention of building on low lying costs ( tsunamis).
- Avoid areas to close to volcanoes.
- Avoid areas where liquefaction is likely.
- Avoid base of rock faces where debris & rocks might slide.
Benefits:
Low cost
Relocates people & infrastructure away from areas of high risk.
Issues:
Prevents economic development in some coastal areas.
Requires strict law enforcement.
How can preparedness be used to lessening human vulnerability to geophysical hazards? And what are the benefits and issues?
Preparedness:
- Earthquake kits ( essential household supplies – water, food, battery powered radio, blankets) kept in safe place at home.
- Preparation days
- Risk education
- Household adjustments – nail furniture, install ‘smart meters’ which cut of gas & prevent fires.
Benefits:
Low cost – can be organised by NGOs.
Can save lives at a local scale.
Issues:
Property still damaged.
Harder to implement in isolated rural areas.
How can insurance be used to lessening human vulnerability to geophysical hazards? And what are the benefits and issues?
Insurance: Compensation given
Benefits:
Allows for economic recovery.
Some companies require buildings to meet safety codes.
May provide temporary accommodation after event.
Issues:
Does not save lives.
Few people in developing countries can afford. Insurance companies charge according to the degree of risk posed by a hazard and in areas of very high risk insurance may not be available. People might not perceive there to be a risk e.g. only 10% of Californians are insured, even though 10,000 earthquakes occur every year.
What are methods of prediction and forecasting for earthquakes?
What are methods of prediction and forecasting for volcanoes?
What are methods of prediction and forecasting for tsunamis?
Define: Mitigation
Mitigation: Actions and interventions to reduce vulnerability. It refers to pre-event planning and may include fault and geology mapping, hazard mapping e.g. liquefaction risk, landslide risk, land use zoning, early warning systems, seismic design and infrastructure defences, lava diversion, preparation.
Define: Preparedness
Preparedness: Ways in which communities can adapt to live with a natural hazard.
What mitigation strategies can be put in place for landslides?
- Land use zoning
- Banning logging on steep slopes/ planting trees
- Improving drainage/diverting water - remove water from the slope altogether and prevent shear force from building up through pore-water pressure.
- Restraining structures e.g. gabions/walls – provides additional shear strength by building support at the base of the slope.
- Netting/rock traps
- Increase slope stability by terracing, therefore reducing the slope angle and preventing damage to a settlement.
- Piling -involves drilling supporting rods into the slope to provide increased stability.
What are small scale mitigations that can be put in place for landslides?
- Mesh curtains - A flexible wire mesh is placed over the slope. This prevents small rock falls from causing damage or harm
- Bench steps - These act as steps in the slope and provide protection against rockfall. Some argue they are ugly and look very artificial.
- Soil nails - This involves drilling steel bars into the slope to provide stability through the strata.
- Soil grillage - This technique involves integrating metal grids into the slope to provide extra stability. It’s cost effective and can be integrated with more natural landscaping and trees.
What mitigation strategies can be put in place for earthquakes?
Earthquakes don’t kill people, collapsing buildings do. It is thus really important to make building ductile. (capacity of a beam or foundation to deform without losing its bearing capacity).
Aseismic buildings:
- Cross-bracing
- Using counterweights at the top of the building such as tanks of water that counter sway due to the lag in the movement of water prove to be less effective on their own compared to isolated bases.
- Adding rubber shocker absorbers – allow building to rock back & forth.
- Deep foundations
- Base isolation
- Cheaper option is using malleable substances e.g. straw, metal roof, bamboo…
What are the benefits and issues of earthquake mitigation?
Benefits:
- Protects people & property.
- Financially possible in HICs.
- Basic design can be replicated in LICs.
Issues:
- High costs for tall buildings.
- Older buildings and homes for people on low incomes are difficult to protect.
What are tsunami mitigation/defences?
- Hard engineering - Building sea walls & breakwaters. The latter slows down incoming waves.
- Homes may be raised or built with flooding in mind.
- Natural defences – planting & protecting mangrove forests.
What are the benefits or issues of tsunami defences?
Benefits:
- Reduces damage.
- Provides a sense of security.
Issues:
- Can be overtopped & thus lead to a false sense of security.
- Very high cost – Japan spent $11bn on building 400km of sea wall
- Unsightly – some of the Japanese are 15m high and residents can no longer see the sea & can no longer see oncoming tsunami waves.
What mitigation strategies can be put in place for volcanoes
- Hi-tech monitoring: Used to monitor volcanoes e.g. Tiltmeter, thermal imaging, seismometers, GPS meters.
- Lava Diversions: Diverted barrier or diversion channels, Water cooling ( spraying – slows movement), Draining crater lakes reduces formation of lahars.
What are the benefits, issues and examples of hi-tech monitoring to mitigate volcanoes?
- Benefits: Warnings/evacuations can save lives.
- Issues: Costly, mainly found in HICs/NEES. Possibility of cry wolf syndrome, property is still damaged.
- Example: GPS monitoring means that transmitters/receivers are placed around the volcano allowing scientists to monitor and record data about the volcano’s activity and changes thus allowing for a timely evacuation of the populations affected by potential
volcanic eruptions.
What are the benefits, issues and examples of lava diversions to mitigate volcanoes?
- Benefits: Directs lava away from people and buildings & relatively low cost.
- Issues: Only works for basaltic lava & Not feasible for majority of explosive volcanoes.
- Example: Lava diversions can be building walls or incorporating lava tubes as is used for volcanic eruptions on Mount Etna which have helped divert the lava from the more populous areas and so saving lives and property .
What are the 3 main stages of response to a disaster?
- Relief ( hours to days) immediate response, attempts to get people to safety.
- Rehabilitation (days, weeks & sometimes months) attempt to get people back into their homes, so they are less vulnerable to secondary impacts e.g. disease & trauma.
- Reconstruction ( weeks, months, years) long-term rebuilding of the economy and or society. Has the potential to return the quality of life to its original level or to improve it by decreasing the vulnerability of the community to a recurring event.
How can relief be effective?
- Effectiveness of this depends upon the capacity of the government, relationship with neighbouring countries & the international community, as well as accessibility & degree of remoteness.
- Speed & effectiveness is critical at this stage.
- HICs tend to have agencies responsible for leading this e.g. Civil Defence in Italy, which also has a regional presence, with permanent professional leaders & 1,000s of trained volunteers, who can mobilise a response in hours. Make shift hospitals & temporary shelters were set up after the L’Aquila earthquake. In LICS Red Cross & UNICEF will provide support.
What are the different techniques for search & rescue & technology?
- Trained search dogs can be sent into buildings deemed upfit for humans.
- Life detection units ( remotely managed devices) can be pushed into small spaces.
- NASA’s Finder – microwave radar to detect human heartbeats & breathing. Can detect through 9m of rubble ad 6m of solid concrete.
- Drones can fly over and survey & can be used long term to map land use pressures.
- GPS – rescue teams can be tracked in large collapsed building.
- Online mapping e.g. Google Earth can help aid agencies mobilise logistical operations. Can be combined with open-sourcing, where people on the ground can contribute & map issues – damage, injuries, aid needed. This leads can lead to a more effective response & avoid duplication.
What are the different factors which hinder relief?
Factors which hinder relief:
- Government capacity
- Relationships
- Community resilience
- Timing of event
- Magnitude of event
- Spatial extent – remote/access
- Scale of loss
- Preparedness
- Secondary hazards
Who move into rehabilitation stage quicker and what is an example?
HICs tend to move into this stage quicker. Following the L’Aquila earthquake in 2009 the rapid response enabled them to move into this phase within days and not weeks. Tent villages were established – family shelters, kitchen, dining tents, post office, creche, clinic & temporary school.
What happened in L’Aquila for reconstruction phase?
– The government rapidly rebuilt apartment blocks on the outskirts of the town, as the town was deemed unsafe & a red zone.
- People were rehoused and given free rent for 12 months and free appliances and even clothing and bedding, but the speed of construction had left community groups out of the decision making process and people were dissatisfied with the lack of community outdoor space, so integral to Italian culture. People complained about the lack of soul and services and that people no longer felt connected with each other. In the speed to rebuild, housing authorities had forgotten to integrate basic community participation. Locals stormed building sites, as they were frustrated their own town was not being rebuilt.
What happened in Japan for reconstruction phase?
In Japan, the locals were consulted more, with many towns voting against higher sea walls and opting to relocate to higher ground.
