Natural Disasters - Earthquake
Forest fire -
Hurricanes - Tornado - Tsunami
Earthquakes are caused by a sudden shift / movement deep under
ground in the Earth's tectonic plates. On the surface, we
see this as the shaking of the ground, causing damage to poorly
The most powerful earthquakes can destroy even the best built
Earthquakes can also cause other disasters including
Earthquakes occur unpredictably along fault lines, capable of
killing thousands of people.
Seismometers can detect the strength of an earthquake. It
gives a number on the Richter scale devised by Charles Richter:
||Frequency of Occurrence
||Less than 2.0
||Microearthquakes, not felt.
||About 8,000 per day
||Generally not felt, but recorded.
||About 1,000 per day
||Often felt, but rarely causes damage.
||49,000 per year (est.)
||Noticeable shaking of indoor items, rattling noises. Significant
||6,200 per year (est.)
||Can cause major damage to poorly constructed buildings over small
regions. At most slight damage to well-designed buildings.
||800 per year
||Can be destructive in areas up to about 100 miles across in
||120 per year
||Can cause serious damage over larger areas.
||18 per year
||Can cause serious damage in areas several hundred miles across.
||1 per year
||9.0 or greater
||Devastating in areas several thousand miles across.
||1 per 20 years
Examples of earthquakes include:
Damage from the 1906 San Francisco
Section of collapsed freeway after the 1989
Loma Prieta earthquake.
Global earthquake epicenters, 1963–1998
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