Earthquakes can be devastating. They remind us that the earth is constantly moving. They are caused by the motion of 'tectonic plates' - individual sections that make up the Earth's surface like panels on a football. Immense strain accumulates along 'fault lines' where adjacent plates meet. When the rock separating the plates give way, sudden 'seismic' ground-shaking movement occurs.
In 2001 an earthquake devastated much of Gujarat state in north-western India, killing an estimated 30,000 people and making more than a million homeless.
Volcanoes are explosions of molten rock which comes from deep in the earth. It's estimated that one in ten of the world's population lives within 'danger range' of volcanoes. In 2002 Goma, in the Democratic Republic of Congo, was engulfed by lava from a volcano, forcing hundreds of thousands of people to flee.
Tsunami are giant waves which travel up to 500km/hour. They are caused by underwater shocks, such as earthquakes or volcanoes. Following the world's biggest earthquake off the coast of Chile in 1960, a series of waves created havoc around the Pacific Rim. It caused 56 deaths in Hawaii, 32 deaths in the Philippines, and 138 deaths in Japan - 10,000 miles away.
Tornado. A tornado is a violent whirling wind. A tornado can travel at 300 miles per hour causing a great deal of damage. Heavy objects, like cars and cows, can be sucked up and flung around. The United Kingdom is actually the world's most tornado-prone nation.
Landslides are caused by instability on a slope - often made worse by rain and deforestation.