Tectonics EQ3 Flashcards
The numbers of disasters and the impacts of disasters are not static. There is, however, a difference between the two broad categories of natural hazards:
- Hydrometeorological hazards, such as floods, storms, cyclones and drought, appear to have become more common over time, perhaps because of global warming and human environmental management issues such as deforestation.
- Tectonic disasters, i.e. the events, have not increased or decreased over time. The number of events is broadly the same decade over decade.
Have tectonic disasters increased or decreased over time?
They have not increased or decreased.
- No. of events broadly the same decade over decade
What are the trends for natural hazards?
- There has been no change in the number of earthquake disasters since 1980, which varies between 15 and 40 each year.
- Earthquake deaths are very variable: there were fewer than 1000 deaths worldwide in 2012 and 2014, yet more than 200,000 in 2010 and 2004. Overall, there are fewer earthquake deaths than there were 30-40 years ago, but the impact of single megadisasters skews the data.
- Megadisasters are high-magnitude, high-impact, infrequent disasters that affect multiple countries (directly or indirectly), so their impacts are regional or even global.
- The trend for earthquake economic losses is upwards, averaging about $20-40 billion per year but, once again, this is affected by very few large events.
What are the trends for volcanic disasters?
Volcanic disasters are much less frequent than earthquake ones and deaths from eruptions are now rare. The last time an eruption killed more than 1000 people was in Cameron in 1986 (Lake Nyos) and only seven eruptions since 1980 have killed more than 100 people. However, the numbers affected can be very large because of the mass evacuation of people around an erupting volcano, e.g. 350,000 affected (evacuated) with the eruption of Mt Merapi in Indonesia in 2010, but only 300 deaths.
Why have deaths fallen over time?
How much have deaths fallen between 1975 and 1980?
How did deaths fall from 2000-2015?
Better response management, preparation and prediction. Better warning systems, improved building codes.
120,000 - 90,000 per year.
70,000 - 20,000 per year.
Why did the number of reported disasters increase and then stabilise?
How was reporting and coverage decades ago
Improvement in data coverage and accuracy of data increases.
Disasters went unreported
How can the collection of disaster data be incomplete or inaccurate?
- When a disaster strikes, the immediate focus is on organising the rescue and aid efforts – not on collecting data.
- No single organisation is responsible for collecting data. As a result, methods vary in the data collection.
- There are even differences in the definitions of some of the key terms and categories used, such as disaster and damage.
- It is difficult to gather data from remote areas, so it is likely that underreporting of deaths and damage occurs in these areas, the very places in need of help and disaster planning.
What is the recent number of reported disasters?
How did levels of reported disasters change from 1975 - 2015?
Fallen, suggesting fewer hazard events become disasters.
- 1975- 900
- 2003 - 450
- 2015 - 360 (stabilised)
Explain the number of people affected by disasters:
Continues to rise as populations grow and more people live in risky locations.
What are the trends of economic costs due to tectonic hazards?
Economic losses from tectonic disasters continue to rise. More people, who are more affluent, have more property to lose. This is increasingly true in emerging countries as well as developed ones.
The trend for earthquake economic losses is upwards, averaging about $20-40 billion per year but, once again, this is affected by very few large events.
- the economic Cost of the magnitude 9.0 japan earthquake and tsunami in 2011 – about US$240m – where the official death toll was 15,893. compare that with the lower magnitude 7.0 Haiti earthquake in 2010, which killed about 230,000 Haitians and had an economic cost of just US$14 billion. Haiti is one of the poorest and least developed countries in the world, and japan is one of the richest and most developed.
What are the trends of meteorological, hydrological, geophysical, climatological and biological disasters?
Biological disasters have declined since 2000. This could be due to better healthcare systems. All other disasters have also seen a decline but did reach a peak.
Why does the media focus on the sudden onset?
What types of hazards have been increasing and why?
More dramatically, newsworthy, perhaps giving the impression that there is actually more tectonics.
Hydro-meteorological due to the effects of climate change.
What is a mega-disaster?
- Are large scale (in spatial scale orin impact), pose problems for effective management and require coordinated, usually international, responses.
- They are high-impact, low-probability (HILP) events.
- Likely range of impactsfollowing a VEI 6+.
- A huge volcanic eruptioncould have a huge rangeof impacts.
- Yellowstone’s CalderaSuper volcanos would potentially change the climate completely.
What are the two case studies of mega-disasters?
Iceland 2010
Japan 2011
What happened in Iceland 2010?
- Erupted 10m^3 of ash in one week up to an amplitude of about 9km.
European airspace shut down:
- The ash cloud from the eruption had a disruptive effect on air travel because of the dangers of jet engines ingesting ash: over 100,000 cancelled flights costing over £1 billion in losses.
- Tourism and airline industries lost significant income due to the fact that people could not move.
- Nissan plant in Japan had to halt production as they did not have certain parts that would be flown from Ireland.
- African countries (including Kenya, Ghana and Zambia) lost an estimated $ 65 million due to the loss of perishable goods; (fruit, flowers and vegetables) that couldn’t be flown to Europe.
What happened in Japan 2011?
- 5% loss in overall GDP.
- Damage to Fukushima nuclear plant disabled the power supply and affected the cooling of three reactors, causing radioactive releases.
- Toyota & Sony halted their production.
- Worldwide availability and cost of LNG (Liquefied Natural Gas) were affected as Japan’s demand increased.
- Germany and Italy immediately shut down their nuclear reactors and stopped plans for new ones.
What is a multi-hazard zone?
Multiple hazard zones are places where two or more natural hazards occur, and in some cases interact to produce complex disasters. Examples are California, Indonesia and Japan. These locations:
What is it about the multi-hazard zones which lead to tectonic hazards?
- Are tectonically active and so earthquakes (and often eruptions) are common.
- Are geologically young with unstable mountain zones prone to landslides.
- Are often on major storm tracks either in the mid-latitudes or on tropical cyclone tracks.
- May suffer from global climate perturbations such as El Niño and La Niña.
What are 2 examples of a multi-hazard zone?
Philippines and Vanuatu
Why is the Philippines a multi-hazard zone?
- The Philippines sits across a major convergent plate boundary so it faces significant risk from both volcanoes and earthquakes.
- Its northeastern coast faces the Pacific (one of the world’s tsunami-prone oceans).
- The Philippines lies within southeast Asia’s major typhoon belt. In most years, it is affected by 15 typhoons and actually struck by 6 to 9. These events not only bring strong winds and heavy rainfall but also increase the risk of flooding and landslides.
- It has a tropical monsoon climate, so it’s subject to heavy annual rains.
- The Philippines has 47 volcanoes – 22 of which are active. Over 30% of the country’s population lives within 30 km of a volcano.
- Landslides are common, due to a combination of steep topography, high levels of deforestation and high rainfall.
What is the vulnerability of the Philippines?
The Philippines is a rapidly developing lower-middle-income country. Its development, and a fast-growing population, have led to rapid urbanisation and a high population density. Many of the countries poor live in coastal areas, Storm surges, and flooding in tsunamis are made worse by poorly constructed housing infrastructure. 25% of the population lives in poverty.
What are the challenges of multi-hazard zones?
One hazard event can cause or increase hazards. For example, an earthquake in the Philippines in 2006:
- Killed 15 people, injured 100 and damaged or destroyed 800 buildings. Generated a local tsunami that was 3 m high. Triggered landslides, which breached the crater wall of the volcano and fell into a lake, creating a flood that washed away houses.
For example, in 2013, the Philippines was struck by three natural disasters within three months. An earthquake in October killed 223 people. Typhoon Haiyan in November killed 6201 people and floods from a tropical depression in January 2014 killed 64 people. The string of disasters left the Philippine government and aid agencies operating in a near-constant state of emergency.
What has the Philippine government done to help increase resilience and reduce risk?
In 2009 the Philippine government passed disaster risk management to help increase resilience and reduce risk. This included removing illegal settlers from areas prone to Hydrometeorological hazards. There is an advisory system for meteorological events and monitoring of volcanoes, mapping of food systems in Manila, the capital has taken place, and there is a comprehensive 2011 to 2028 national disaster risk reduction and management plan for the whole country. The national disaster response pillar provides information and links all government and relief agencies, and volunteers for coordination.
What does prediction mean?
What is forecasting?
- Prediction means knowing when and where a natural hazard will strike on a spatial and temporal scale that can be acted on meaningfully in terms of evacuation.
- Forecasting is much less precise than a prediction and provides a percentage change of a hazard occurring (e.g. a 25% of a magnitude 7.0 earthquake occurring in the next 20 years)
How do scientists predict earthquakes?
- Earthquake risk can be forecast since it is basedon a statistical likelihood of an event happening at a particular location.
- These forecasts are based on data and evidence gathered from global seismic monitoring historical data is already used.
- Long-term forecasts (years to decades) are currently more reliable than short to medium-term (days to months).
- Forecasting is very important as it can encourage governments to enforce more stringent building codes in high-risk areas and to implement evacuation procedures.
- Only areas at high risk can be identified (risk forecasting), plus areas that are likely to suffer severe ground shaking and liquefaction; this can be used for land-use zoning purposes.
- ‘Seismic gaps’, i.e. areas that have not experienced an earthquake for some time and are ‘overdue’ can point to areas of high risk.
