TECTONICS EQ3 Flashcards
How succesful is the management of tectonic hazards and disasters? (23 cards)
What are the global disaster trends?
The number of recorded disasters has increased significantly since 1960. There are several reasons for this, including ;
-increased population: this has grown from 3-8 billion since 1960, meaning more people are likely to be impacted by a hazard
-increased population density in urban and coastal areas: increases the global population
-increased monitoring and reporting: means more hazard events are recorded
-Most of the increase is due to floods and extreme weather
What are the tectonic disaster trends?
- Numbers have fluctuated since 1960, but have remained generally steady
- A slight increase in the number does not mean there are more frequent or worse earthquakes; it results from population growth, making more people live in earthquake-prone regions
What is the trend in the number of deaths?
-decreased since 1960
as a result of;
-improved building construction
-increased monitoring
-greater preparation and planning
-education
-improved warning systems
-level of development
-location
-Impact of mega disasters
-volcanic eruptions vs earthquakes
What are the economic cost trends?
-increased since 1960
-As countries develop, the cost of repairing and rebuilding increases
- increased wealth means more possessions and property that can be damaged
-Infrastructure is more sophisticated and expensive to replace, eg electric grids
-As more people are affected, the cost increases
How does the economic cost of disasters vary?
-Affected by whether the country is developing or developed
-Economic cost in US$ tends to be higher in developed countries
-The impact on GDP tends to be greater in developing countries
Should we trust disaster statistics?
-Direct or indirect deaths from subsequent hazards or associated diseases are counted
- location; local-regional events in remote areas are often unrecorded
- Deaths/casualties may be subject to political bias
-Stats are difficult to collect in rural developing areas
What is a Multiple Hazard zone?
A part of the world that is exposed to a range of hazards.
CASE STUDY: THE PHILIPPINES
-An archipelago consisting of over 7600 islands
- The capital is Manila
-population estimates. 115.6 million
-population density of 385.2 people per kilometre
-50% of the population is urban
-74% of the population and 60% of the land are vulnerable to hazards.
-In 2019/2020, 4 typhoons, one eruption and several earthquakes occurred.
Located on the Pacific Ring of Fire
-convergent boundaries causing earthquakes and volcanoes
-multiple subduction zones, increasing volcanic activity
2.81 people live within 30km of the Taal volcano
Typhoons are active from June to September, 15-20 occur
What is a Mega-disaster?
A high magnitude high high-impact, infrequent disaster that affects several countries directly or indirectly
-Large-scale spatial or economic
-high impact, low probability
-cause problems for effective management
-often requires international support
-affect more than one country directly or indirectly
Globalisation has made some areas more vulnerable
Can volcanic eruptions be predicted?
Yes, very easy to predict using thermal imaging, satellites, tiltmeters and measuring gases.
Can earthquakes be predicted?
Not really; swarms of small earthquakes, increased radon in the water and unusual behaviour of animals have all been used to try and predict earthquakes. However, these precursors occur without an earthquake, so real prediction is not possible, but probabilistic forecasts can be made on a scientific basis.
What is mitigation?
Reducing or removing the effects of a tectonic event
What is adaptation?
Responding to the effects of a hazard to minimise harm
What is the hazard management cycle?
The four-stage process used to manage hazards and disasters, aiming to reduce their impact and improve preparedness for future events
Mitigation- reducing the scale of the next disaster, by land use zoning and hazard-resistant buildings and infrastructure
Preparation- community education and resilience, including how to act before, during and after a disaster. Prediction, warning and evacuation technology systems.
Response- immediate help in the form of rescue to save lives and aid to keep people alive, emergency good shelter and water.
recovery- rebuilding infrastructure and services, rehabilitating the injured and their lives
What is the Park Model?
Shows the importance of recovery, known as the disaster response curve.
Provides a visual illustration of the impact of the disaster and can be used to compare different events.
What does it mean to modify the cause?
Addressing the root causes or underlying factors that contribute to a hazard’s impact, rather than simply responding to the event itself.
How does earthquake-resistant design help to modify the event?
-involves reducing the chance of building collapse in built-up areas, eg, cross braces, base isolators, mass dampers and shear walls, etc.
- can be highly effective; Tokyo and Sendai have constructed their cities with 87% of modern buildings to seismic standards
How does the diversion of lava flow and lahars help to modify the event?
- saves properties rather than lives and changes the flow of lava out of areas of risk. Eg Catania in Sicily diverted the lava towards another town in the 17th century
Lava flow can be unpredictable, and there are ethical issues of where it is being diverted.
How does land use zoning help to modify the event?
Designing settlements so that high-risk areas are not built upon with high-value land uses. For example, New Zealand red-zoned badly damaged areas of Christchurch and turned them into woodlands and parks
How can engineering solutions be used to help modify the event?
building defences to reduce the impacts of secondary hazards
eg. tsunai flood walls
can be highly effective at stopping hazards associated with tsunami waves
reduces the likelihood of effective evacuation as residents get a false sense of security
How can we modify the vulnerability and resilience?
Hi-tech monitoring, prediction, forecasting and warnings:
-Prediction is only effective for volcanoes
-There is a growing number of warning systems, eg, KNET in Japan (still not accessible to all communities)
-Forecasting can influence risk maps and inform land use planning when effective
Improvements in community preparedness:
-involves sharing local resources to help one another during or after an event
-can be highly effective, but people may lack resources
Public awareness and education
-Drills in place to gain knowledge
strict building codes
-widespread education
How can we modify the loss of an event?
-Effective search and rescue operations
-provisions of emergency shelters, food, water, and healthcare
-Effective use of aid and NGOS
-insurance and financial stability
- working with groups and individuals to change behaviours
-crisis mapping
CASE STUDY: CHRISTCHURCH 2011
-185 people were killed
-3130 were injured
-6800 received minor injuries
-100,000 properties damaged, 10,000 demolished by earthquake
-28 billion dollars of damage caused
-Liquefaction destroyed many roads and buildings
-$7 million of aid was provided
