解释我们如何预测自然灾害

What impact do you think it has on people who live near the centre of an earthquake?
How do you think we can mitigate against climate change?

The Science Behind the Science
Natural hazards are usually extreme events that have occurred naturally and that can potentially cause harm to humans. There are usually three main types: internal processes, surface processes, and severe weather patterns.  

Internal processes include earthquakes and volcanic eruptions. Earthquakes arise when there are often two large sections of Earth’s crust that slip or misalign with one another. In other words, earthquakes happen when there is friction between tectonic plates. Friction causes the plates to lock together in certain places, but they keep on moving, with restriction, of course. It is a build up in this tension and pressure in the stuck sections that result in the sudden movement of the plate and thus an earthquake. It is very difficult for scientists to predict earthquakes. Instead, they look for fault lines where the plates have become stuck so that they are aware of where an earthquake may occur.

Volcanoes are different to earthquakes. They come about when there is an opening in the Earth’s crust. This opening causes the magma (hot liquid rock) to come to surface and erupt out of the ground. Different types of volcanoes exist. Volcanologists predict volcanic eruptions. Seismometers (seismographs) pinpoint earthquakes that can track the rise and movement of magma. Scientists often look for signs too. They will use previous monitoring of eruptions to integrate time data which highlights warnings of potential impending eruptions. Warning signs may include smoke or gases being released. Satellites are used to observe the ground, and observation of volcanic samples also helps to predict where another may strike.  

Surface processes are another type of natural hazard. These processes include tsunamis and mass wasting. Tsunamis are very large and powerful waves that come ashore and cause a lot of damage. They flood and destroy cities and homes. Tsunamis arise due to displacement of or rapid movements of water. Many tsunamis are made by earthquakes: the shifting of the Earth’s crust can open gaps in the ocean floor and thus cause a tsunami. Predicting tsunamis is hard. Scientists usually gather the information from earthquake predictions or follow ups.

Mass wasting is also another type of hazard. Mass wasting is the large movement of rocks, soil and debris downwards because of gravity.  

Severe weather events include hurricanes, flooding, tornadoes, and droughts. Hurricanes can be predicted using seasonal statistics and by early sign tracking, which is following a hurricane once it begins to move. Tornadoes can be predicted through the observation of  differing weather patterns and climates.