A hazard is something that's a potential threat to human life or property. Tectonic hazards (e.g. earthquakes, volcanoes and tsunamis) are hazards caused by movement of tectonic plates. Tectonic hazards can have many impacts on people and their environment. However, some of these impacts can be reduced by management strategies such as prediction, building techniques, planning and education.
Predicting when and where a hazard will occur can help: Earthquakes: 1) It's currently impossible to predict when an earthquake will happen, but there can be clues that an earthquake is about to happen, e.g. small tremors, cracks appearing in rocks and strange animal behaviour (e.g. rats abandoning nests). 2) Earthquake warning systems can detect P waves, but only after an earthquake has begun. These waves travel faster than other types of seismic wave and cause less damage so they can be used as a warning for stronger tremors. For example, Japan's Earthquake Early Warning system was set up in 2007 and warns people by TV and radio. However, even far away from the epicentre the warnings may only arrive a few seconds before the strong tremors. 3) It's possible to predict where future earthquakes may happen using data from past earthquakes- these places can prepare themselves for the impacts of an earthquake. Volcanoes: 1) Unlike earthquakes, i's possible to roughly predict when a volcanic eruption will happen. For example, tiny earthquakes and changes in the shape of the volcano (e.g. bulges in the land where magma has built up under it) can mean an eruption is likely 2) Prediction allows time for people to be evacuated, e.g. 60000 people were evacuated from the area around Mount Pinatubo in the Philippines before it erupted in 1991. Although 800 people died, this figure would've been much higher without the evacuation 3) However, even when there's enough warning it can be difficult to evacuate people. Often people don't want to abandon their homes or they don't believe the eruption will really happen. Tsunamis: 1) Tsunami warning systems rely on earthquake detection systems. If an earthquake occurs in a place that's likely to cause a tsunami (e.g. under an ocean), a warning is issued. 2) There are tsunami warning centres all around the world. For example, The USA's National Oceanic and Atmospheric Administration (NOAA) runs centres in Alaska and Hawaii. 3) Early warnings give people time to evacuate. However, they rely on good communication systems. If people don't receive the warning message they wont evacuate. Also, if an earthquake happens very close to land, the tsunami will reach the coast very quickly and people wont be warned early enough to evacuate. Disaster Management Cycle:
Disaster management aims to reduce, or avoid, the potential losses from hazards, assure prompt and appropriate assistance to victims of disaster, and achieve rapid and effective recovery. The Disaster management cycle illustrates the ongoing process by which governments, businesses, and civil society plan for and reduce the impact of disasters, react during and immediately following a disaster, and take steps to recover after a disaster has occurred. Appropriate actions at all points in the cycle lead to greater preparedness, better warnings, reduced vulnerability or the prevention of disasters during the next iteration of the cycle. The complete disaster management cycle includes the shaping of public policies and plans that either modify the causes of disasters or mitigate their effects on people, property, and infrastructure. |
Building Techniques can physically protect people:
Building techniques can be used to protect people from some of the effects of tectonic hazards. However, they're more expensive than standard building techniques. Earthquakes: 1) Buildings can be designed to withstand earthquakes, e.g. by using strong material like reinforced concrete or building special foundations that absorb an earthquake's energy 2) Construction laws in some earthquake-prone countries (e.g. Japan and the US) have become stricter in recent years - this means that newer buildings are more likely to be able to withstand earthquakes. Volcanoes: 1) Buildings can't be designed to withstand the lava flows. However, they can be strengthened so they're less likely to collapse due to the weight of falling ash 2) It's sometimes possible to divert the lava from a volcano away from settlements using barriers. For example, when Etna in Italy erupted in 1983, a rubble barrier 10m high and 400m long was built on its slopes, which successfully diverted the lava flow. However, this is only possible where the lava is slow moving and there's sufficient warning. Tsunamis: 1) Buildings designed with raised, open foundations and made of strong materials such as concrete are less likely to be damaged by the force of water during a tsunami 2) In some places e.g. Hokkaido (Japan), tsunami walls have been built around settlements to protect them. They are not always effective as proved in its recent tsunami. Some Factors can increase the severity of the Impacts:
Development Level of a Country: 1) The impacts are higher in less developed countries than in more developed countries. The main reason is that they don't have the money for disaster preparation on response, e.g. they have no money to spend on training emergency teams 2) Also, the buildings are poorer quality than in more developed countries, so are more easily damaged by hazards 3) Infrastructure is often poorer, making it more difficult for emergency services to reach affected areas. 4) Health care isn't as good in less developed countries, so they struggle to treat large numbers of casualties. 5) Many people depend on agriculture in less developed countries, which is often badly affected by eruptions or tsunamis 6) However, the economic impact is often higher in more developed countries as the buildings and infrastructure damaged are worth a lot of money Population: 1) Obviously, the more people in an area, the more people will be affected by a disaster 2) Densely populated areas such as cities have a lot of buildings. Collapsing buildings pose a big risk to life, particularly during earthquakes 3) It can be difficult to evacuate large numbers of people because the routes are often limited. For example, if everyone in an area drives away from a volcano the roads will quickly become clogged and people will be trapped. |