Earthquakes

An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph. The moment magnitude of an earthquake is conventionally reported, with magnitude 3 or lower earthquakes being mostly imperceptible and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale.

The moment magnitude of an earthquake is conventionally reported. Earthquakes can be recorded by seismometers up to great distances, because seismic waves travel through the whole Earth's interior. The absolute magnitude of a quake is conventionally reported by numbers on the Moment magnitude scale, which is formerly Richter scale. Magnitude 7 causing serious damage over large areas. Magnitude 3 or lower earthquakes being mostly imperceptible. The felt magnitude is reported using the modified Mercalli scale (intensity II-XII).

Minor earthquakes occur nearly constantly around the world in places like California and Alaska in the US, as well as in Guatemala. Chile, Peru, Indonesia, Iran, Pakistan, the Azores in Portugal, Turkey, New Zealand, Greece, Italy, and Japan, but earthquakes can occur almost anywhere, including New York City, London, and Australia. Larger earthquakes occur less frequently. For example, in the United Kingdom, it has been calculated that the average recurrences are: an earthquake of 3.7 - 4.6 every year, an earthquake of 4.7 - 5.5 every 10 years, and an earthquake of 5.6 or larger every 100 years.

Earthquakes may lead to disease, lack of basic necessities, loss of life, higher insurance premiums, general property damage, road and bridge damage, and collapse or future collapse of buildings. Therefore, we must be prepared for earthquakes at any time. People should be evacuated once earthquake has been predicted. Stronger infrastructure should also be built to reduce the chance of buildings collapsing.