Natural disasters take many different forms and can happen without warning. Earthquakes, floods, volcanoes, droughts, typhoons, and hurricanes are all natural disasters.

The earthquake of 26 December 2004 resulted in one of the worst natural disasters in living memory. It was a massive (大规模的) underwater quake and occurred in the Indian Ocean. This caused a huge tsunami to cross the Indian Ocean. It destroyed coastlines and communities and brought death and destruction (破坏) to many people. The survivors needed fresh water, food and shelter as well as medical help. People from all over the world collect money to help them.

The surface of the Earth has not always looked as it does today; it is moving continuously although very slowly and has done so for billions of years. This is one cause of earthquakes, when one section of the Earth crashes with another. Scientists can predict (预测) where this might happen and the area between plates is called a fault line. However, earthquakes do not always happen on fault lines, which is why they are so dangerous and unpredictable.

All the disasters are very dangerous and continue to kill thousands of people each year, but they are nowhere near the most dangerous disaster to ever happen on earth. One type of event in the earth’s history has regularly killed millions of beings: asteroid impacts (小行星撞击). About once every million years the Earth is hit by a piece of rock and ice from space large enough to cause massive destruction (including earthquakes, volcanoes and ice ages) and sometimes to kill entire species. Sixty-five million years ago more than half the earth’s species were killed by such a disaster, including all the dinosaurs. Disasters on the Earth may seem dangerous, but the biggest threat to humans is likely to come from space.

In natural disaster — a hurricane, flood, volcanic eruption, or other catastrophes (灾难) — minutes and even seconds of warning can make the difference between life and death. Because of this, scientists are working to use the latest technological advances to predict when and where disasters will happen. They are also studying how to analyse and communicate this information in the best way once it is obtained.

On September 29, 1998, hurricane Georges made landfall in Biloxi, Mississippi, after damaging Haiti, the Dominican Republic, Puerto Rico, and several islands of the Caribbean badly with torrential rains and winds up to 160 km per hour. Few people lost their lives along the Gulf Coast of the United States, although hundreds died in the Caribbean.

This was a very different outcome from 1900, when a powerful Gulf Coast hurricane had made an unexpected direct hit on Galveston, Texas, killing at least 6, 000 people.

Vastly improved hurricane warnings explain the different circumstances at either end of the 20th century — residents of Galveston had no advance warning that a storm was approaching, while residents of Biloxi had been warned days in advance, allowing for extensive safety precautions (预防措施).

While people in Biloxi were thankful for the advance warning, some residents of New Orleans, Louisiana were less satisfied. A day before Georges made landfall, forecasters were predicting that the hurricane had a good chance of striking New Orleans. Because much of New Orleans lies below sea level, the city is at risk from flooding. Emergency management officials must begin evacuations (疏散) well before a storm strikes. But evacuation costs money.Businesses close, tourists leave, and citizens take precautionary measures. The mayor of New Orleans estimated that his city’s preparation for Georges cost more than 50 million. After Georges missed New Orleans, some residents questioned the value of the hurricane forecasts in the face of such high costs.

The different views on the early warnings for Hurricane Georges show some of the complexities related to predicting disasters. Disaster prediction is a process of scientific information to the government officials and other decision makers who must respond to those predictions.

Here is the latest news from BBC.

News One

More than 90 people are now known to have been killed by destructive tornadoes that swept through the Midwest of the United States on Friday. At least 80 were killed in Kentucky and 14 across five other states.

A worker at a Kentucky candle factory told the BBC that many workers had been killed when they worked there. As Peter Bowes reports, what people should do is being discussed when they are warmed that a tornado is on the way. And the owner of that factory has, in fact, been talking about this. But clearly it wasn’t of any use for the people in that building.

News Two

The number of people killed by flash floods in the US state of Tennessee has risen to more than 20 on Tuesday. Now rescue workers are continuing to look for those who are still missing.

Record rainfall of more than 40 centimeters in some areas caused widespread flooding. Buddy Frazier is the mayor (市长) of Waverly, one of the worst affected towns. “I’ve been around a long time, and I’ve been through a lot of events here, and this one really shocked me. “ He said.

News Three

Haiti’s civil protection service says around 1300 people are now known to have lost their lives in Saturday’s powerful earthquake which struck the southwest of the country.

Hospitals in the area are fighting to cut down the number of the injured, which is almost doubled to around 6000 people. In the cities of Jeremies and Les Cayes, rescuers are trying to locate people still trapped under ruins.