Welcome to the unit. Natural disasters are terrible reminders of the power of nature. Watch the video and finish the following exercises. A natural disaster is a sudden natural event that causes great damage and suffering. IT can happen anywhere at any time. Let's look at some examples. An earthquake is a sudden shaking of the earth's surface caused by the movement of plates. Underground earthquakes are most common, where plates meet several million. Small earthquakes happen every year, but most do not cause any damage. Serious earthquakes, however, can destroy entire cities when a terrible earthquake hit san Francisco in nineteen, no six, about three thousand people died and over eighty percent of the city was destroyed. A volcanic interruption occurs when hot gases, volcan cash and even rocks escape through a large opening at the top of a volcano. The gas is an ash, can cause acid rain and even storms. A hot liquid rock moving down the volcano burns everything and anything in its way. The eruption of month, said Helens in one thousand nine hundred eighty, was the worst volcanic disaster in the history of the united states. IT killed fifty seven people and about seven thousand large animals. A landslide happens when a large amount of earth and rock falls down a hill or mountain. Landslides are often caused by heavy rainfall, earthquakes, volcanic interruptions or other natural disasters. Sometimes they are also caused by human activities such as cutting down forests. Serious landslides can cause whole mountain sides to roll away. Villages or towns located in the path of such landslides can be completely destroyed. In two thousand and fourteen, a landslide in india killed at least one hundred and fifty people.