EQ3 - How successful is the management of tectonic hazards and disasters? Flashcards
What are the 2 broad categories of ‘natural hazard’?
- Hydro-met hazards (floods, cyclones, drought etc.)
- Tectonic disasters
The amount of tectonic HAZARDS (earthquakes, volcanos etc.) has increased over time.
True or False?
False - the number of tectonic events is broadly the same decade over decade
The amount of tectonic DISASTERS has stayed the same over time.
True or False?
False - whilst the number of HAZARDS has remained the same, the number of DISASTERS (hazard + vulnerability) has risen
How have disaster-related deaths changed over time, and why?
Deaths have fallen due to better response management, preparation and prediction.
By what number have disaster-related deaths globally dropped from 1975 to 2015?
Dropped by 100,000
120,000 (1975) to 20,000 (2015)
Why did global natural disaster reports increase from 90 (1975) to 450 (2003)?
Better data technology and coverage
By how much has the number of people affected by disasters risen between 1975 and 2015?
55m affected in 1975
260m affected in 2015
Why are we experiencing a trend of significantly more people being affected by natural disasters?
Rapid population growth and density
- many are forced to live in vulnerable locations
What is the typical range in number of earthquake events annually (hasn’t changed since 1980)?
15-40 events annually
Why do earthquake deaths vary so much?
Due to rare megadisasters
What are earthquake ‘megadisasters’?
High-magnitude, infrequent disasters with regional and global impacts
How many earthquake deaths were there worldwide in 2014 compared to 2010
2014 = less than 1000 deaths
2010 = more than 200,000
Overall there are fewer earthquake deaths now than there were 30-40 years ago.
True or False
True
What is the average economic loss due to earthquakes (mostly accounted for by recent megadisasters)
$20-40bn per year
Why are economic losses from tectonic disasters continuing to rise as the world develops?
More people are becoming wealthy and have more property to lose
- This is increasingly true in emerging countries as well as developed nations
Volcanos are more frequent and more deadly than earthquakes.
True or False?
False - deaths from eruptions are now rare
When was the last time a volcanic eruption killed more than 1000 people?
Cameroon 1986
Though deaths from volcanos are usually very low, what statistic is very high?
Number of people affected
- mostly due to mass evacuations of people living around volcanos
Though only 300 people died in Mt. Merapi eruption in Indonesia 2010, how many people were affected (evacuated) by the disaster?
350,000 people evacuated
MEGADISASTER CASE STUDIES HERE : volcano and tsunami’s
What is the name of a place where 2 or more natural hazards can occur and sometimes interact?
Multiple Hazard Zones
- if multiple hazards interact, they can produce complex disasters
What are 3 examples of places where Multiple Hazard Zones exist?
- California
- Indonesia
- Japan
What do all of California, Indonesia and Japan possess that makes them Multiple hazard zones? (4 characteristics)
- Tectonically active (along fault lines)
- Geologically young (mountains prone to landslides)
- Risk of Tropical cyclones (due to latitude)
- Vulnerable to El Nino/El Nina events
What nation did a multiple hazard zone develop after the eruption of Mt. Pinatubo in 1991?
The Philippines
What was the name of the typhoon that struck the Philippines during the 1991 eruption of Mt. Pinatubo, creating a Multiple Hazard Zone?
Typhoon Yunga
What destructive secondary hazard was created by heavy typhoon rainfall during the Mt. Pinatubo eruption in the Philippines (1991)?
Lahars - volcanic ash became waterlogged
What is a common secondary impact in areas of high relief following an earthquake?
Landslides - where slopes are weakened by tremors and fail
- this is especially common in times of heavy rainfall
A multiple hazard zone with COMPLEX hazards requires a combination of what 2 types of hazard?
- Hydro-meteorological (floods, storms etc.)
- Tectonic (earthquakes, volcanos, tsunami’s)
What does prediction mean in regard to natural hazards?
When and where a natural hazard will occur on a spacial and temporal scale
Why is prediction important in terms of natural hazards?
So successful evacuation to take place
What is natural hazard ‘forecasting’ as opposed to prediction?
Forecasting provides a % chance of a hazard occurring
- it is less precise
(e.g 25% chance of a magnitude 7.0 earthquake in the next 20 years)
Can earthquakes be predicted?
No (despite decades of research) - they can only be forecasted
Only which areas can be identified for earthquake risk forecasting?
Only high risk areas
-also areas susceptible to severe ground-shaking or liquefaction (for land-use zoning purposes)
How can ‘seismic gaps’ be used to predict areas of high risk?
These are areas that have not experienced an earthquake and are ‘overdue’
Can volcanos be predicted?
Yes - unlike earthquakes
How does advanced monitoring equipment measure when a volcano is close to eruption?
It measures when the magma chamber fills up
What devices are used to record volcanoes ‘bulging’ as magma rises?
Tiltmeters and strain meters
How are seismometers used to monitor volcano eruption risk?
They identify minor earthquakes often caused by magma movement
What is the function of Gas spectrometers in measuring volcano eruption likelihood?
They analyse gas emissions, some of which are indicative of eruption
Despite 60-80 eruptions per year, what is the biggest reason why death tolls from volcanos are minimal?
Developments in prediction and monitoring technology
(e.g seismometers, gas spectrometers, tiltmeters)
How do seismometers help to detect tsunami’s?
They can tell and earthquake has occurred - ocean monitoring equipment can detect tsunami’s in the open sea
Why can coastal areas sometimes be evacuated in the event of a tsunami, despite their rapid speed?
Ocean monitoring equipment can detect tsunami’s up to 1000km away
How far from the shore can tsunami detection equipment locate tsunami’s?
Up to 1000km away
There was tsunami monitoring equipment present in the Indian Ocean 2004, but this was still not fast enough to warn people on distant coasts.
True or False?
False - there were no warning systems in place
Why are developing nations less likely to be able to access volcano and tsunami monitoring and warning systems?
- Cost of technology is too high to install
- More isolated rural areas with limited communication infrastructure
What does the hazard management cycle illustrate?
The different stages of managing hazards to attempt to reduce the SCALE of a disaster
What are the 4 steps involved with the Hazard Management cycle?
- Response
- Recovery
- Mitigation
- Preparedness
What does the (1) Response stage of the Hazard Management Cycle involve?
Immediate action to save lives
- this includes emergency shelter, medical assistance, food and water
What does the (2) Recovery stage of the Hazard Management Cycle involve?
Rebuilding infrastructure and services and rehabilitating the injured
What does the (3) Mitigation stage of the Hazard Management Cycle involve?
Action to reduce the scale of the next disaster
- this includes land-use zoning and hazard-resistant building design
What does the (4) Preparedness stage of the Hazard Management cycle involve?
Community education on how to act before, during and after an event
- Includes prediction, warning systems and evacuation plans
Which stage of the Hazard Management Cycle may be considered the ‘returning to normal’ state?
The (2) Recovery stage
- However the time this takes varies, from a couple of months to many years
What 4 factors does the successfulness of the (2) Recovery stage depend upon?
- Magnitude
- Level of development in affected area
- Quality of Governance
- Amount of external help
What model best illustrates disaster-response?
The Parks Model
What makes Park’s model unique compared to other hazard models?
It includes a ‘pre-disaster’ stage, focusing on preparedness prior to a hazard event
How can Parks Model be used to compare countries with different levels of development?
It illustrates how developed countries often recover faster and to a higher baseline than less developed countries
According to the Parks Model, developing countries are likely to recover to a higher level of ‘preparedness’ than they had pre-disaster.
True or False?
False - Parks model says developing countries rarely recover fully from disasters making them more vulnerable in the long-term
What are the 3 approaches to modifying tectonic hazards?
- Modify the Event
- Modify the Vulnerability
- Modify the Loss
What is said to be the biggest killer during a natural disaster?
The collapse of buildings
What is the difference micro and macro methods in Hazard Management?
Micro - strengthening individual buildings and structures
Macro - Large-scale protective measures for entire communities (e.g tsunami walls)
Are micro or macro civil engineering methods mostly used to manage earthquakes?
Mainly Micro
- Emphasis on protecting public buildings (e.g hospitals, police stations etc.)
What is the most common example of hard engineering used to manage tsunami’s?
Tsunami Walls
What is one disadvantage of Tsunami walls as a management method?
They only work up to a given amplitude and threshold of wave
What is the most common example of soft engineering used to manage tsunami’s?
Replanting and reforestation of coasts (e.g mangroves)
- vegetation dissipates energy from waves
What 2 ways can volcanoes be modified/managed?
- Diverting flows of lava
- Reinforce house roofs (to withstand deposits of ash)
What is one advantage and disadvantage of land-use zoning as a hazard modification method?
Advantage: Low cost, reduces vulnerability
Disadvantages: Stop development on valuable land, requires strict enforcement
What is one advantage and disadvantages of resistant buildings as hazard modification methods?
Advantage: prevents collapse (protects people and property)
Disadvantage: High cost for large buildings + unaffordable for low-income families
What is one advantage and disadvantage of tsunami defences as a hazard modification method?
Advantage: Reduces damage, provides security
Disadvantage: Very high cost, unattractive, can be overtopped
What is one advantage and disadvantage of lava diversion as a hazard management method?
Advantage: Diverts lava away, low cost
Disadvantages: Only works for low VEI lava
What does modifying vulnerability involve?
Increasing the resilience of a community to increase their capacity to cope
What are the advantages of Hi-Tech Volcano monitoring in reducing the vulnerability of a hazard?
Predicting an eruption is usually possible and warning and evacuations save lives
What are the limitations of Hi-tech volcano monitoring in reducing the vulnerability of a hazard?
- Equipment is costly and so developing countries can rarely afford
- Even if all are evacuated, property is still heavily damaged
What is ‘cry-wolf syndrome’ in regard to hazard warning?
Where predictions (and evacuations) are wrong, so people are less likely to believe the next time a warning is issued
What are examples of community preparedness and education in regard to reducing vulnerability?
Evacuation plans in schools, earthquake kits, essential supply kits
What is an advantage of education and community preparedness in reducing vulnerability?
Low cost option, often provided by NGOs (e.g Red Cross)
What is a limitation of education and community preparedness in reducing vulnerability?
Harder to implement in isolated areas/communities
What is a geographical adaptation that can be made to reduce/stop vulnerability entirely?
Relocation - populations move out of danger zones permanently
Why is relocation, as a method to reduce vulnerability, rarely ever used?
- High population densities in some areas
- Disrupts traditional settlements and communities may be unwilling
What can loss modification informally be referred to as?
‘Picking up the pieces’ AFTER a disaster has occurred
If event and vulnerability modifications have been used effectively, losses from natural disasters should be small.
True or False
True - previous modifications SHOULD reduce the impact
Why is loss modification often used as the main management strategy in developing countries, rather than ‘picking up the pieces’ ?
As they do not have the resources to implement effective event or vulnerability modifications
(e.g 2010 Haiti Earthquake and 2004 Indian Ocean tsunami)
What are the 3 most common methods used to modify loss after a disaster?
- Short-term emergency aid
- Long Term aid
- Insurance
What is short-term emergency aid?
Search and rescue operations, followed by food, water and shelter
What is an advantage of short-term emergency aid in modifying losses after a disaster?
Can reduce death toll - keeps people alive until longer-term help arrives
What are 3 disadvantages of short-term emergency aid in modifying losses after a disaster?
- Very Costly
- Difficult to distribute in isolated areas
- Poor emergency services in developing countries
What is long term aid?
Longer term projects to help a country recover
(e.g reconstruction plans for an affected area)
What is an advantage of long term aid in modifying losses after a disaster?
Reconstruction can ‘build-in’ greater resilience
(e.g land-use zoning or building standards)
What is a disadvantage of long term aid in modifying losses after a disaster?
Very high costs - often dependent on financial support from developed nations
What is insurance, in terms of modifying losses after a disaster?
Financial compensation given to people to replace their losses
What is an advantage of insurance as a method to modify losses after a disaster?
Allows people to recover economically by paying for the assets they lost
What are 2 disadvantages of insurance as a method to modify losses after a disaster?
- It does not save lives
- Few people in developing nations have insurance
