Volcanoes

Volcanoes are dramatic evidence of the powerful forces at work inside the Earth. Eruptions of ash, gas and lava destroy entire cities and kill large numbers of people. Volcanoes also add nutrients to soils, creating perfect conditions for many crops. Some types of volcano make new sections of the tectonic platesthat make up the surface of the Earth. Without volcanoes and… Read More »

Tsunamis

A tsunami, sometimes referred to as a tidal wave, is a series of ocean waves created when anearthquake or other major disturbance displaces a large volume of water. Powerful tsunamis such as the 2004 Indian Ocean event can devastate coastal regions as the waves sweep far inland. Following a quake, tsunamis can travel for thousands of miles. For example,… Read More »

Tornadoes

Tornadoes, or twisters as they are often called, are violent storms that can rip paths of destruction through towns and cities and kill large numbers of people. Their characteristic funnel shapes look very dramatic in photographs and videos, though it is difficult and dangerous to get close enough to take these shots. Tornadoes tend to occur more frequently… Read More »

Supervolcanoes

The term supervolcano was first used in a TV documentary to describe eruptions of more than 1,000 cubic kilometres of magma. Such volcanoesare devastating, but very rare. The last one happened at Toba in Sumatra, Indonesia, 74,000 years ago. The active volcanic system at Yellowstone National Park has resulted in super-eruptions – the most recent happened 640,000 years ago. Yellowstone’s… Read More »

Landslides

A landslide is the movement of rocks and soil down a slope and, when a large slide occurs in an area of dense human habitation, large numbers of people can be killed. In January 2011 mudslides in south-eastern Brazil killed more than 400 people. Many natural events such as heavy rainfall, an earthquake or volcano can trigger a landslide, but human activities… Read More »

Hurricanes

Hurricanes are powerful storms that grow in size over tropical seas. Sometimes these storms lose their power before they reach land, but when they do not they can kill large numbers of people and cause widespread property damage. Hurricane, typhoon and cyclone are regional names for the same type of storm. Weather experts call them tropical cyclones. COPYRIGHT:… Read More »

Forest Fires

Lightning triggers forest fires, or wildfires, but humans have been known to accidentally or intentionally set forests ablaze. Fast moving fires can kill large numbers of people and destroy vast areas of woodland and property. Fires can be good for many ecosystems, which have evolved to cope with these events. A small fire can remove dead brush, but not… Read More »

Floods

Floods have a variety of causes including heavy rainfall, tidal surges and the failure of manmade structures such as dams. During a flood an area of land that is normally dry is covered by water. Heavy rainfall over a short time period caused the 2004 Boscastle flood in north Cornwall, UK. The village of Boscastle, which is located… Read More »

Earthquakes

There are thousands of earthquakes across the Earth each day. Most are too small to be detected without monitoring equipment, but some are powerful enough to destroy a city. Sendai, Los Angles, Kobe, Christchurch and Bam are the names of some of the places that have been affected by powerful earthquakes in recent years. Earthquakes are most common… Read More »

Avalanches

Avalanches are rapid movements of large masses of snow down a slope that commonly occur in mountainous regions. Despite what you may have seen in movies and on television, shouting cannot trigger an avalanche, according to the Utah Avalanche Centre. The UAC says that in 90% of avalanche deaths, it was the weight of the victim or someone in… Read More »