The Richter magnitude scale

Charles Francis Richter was an american seismologist. Together with american-german Beno Gutenberg established a scale to measure earthquakes.

The Richter magnitude scale is arbitrary and logarithmic, so each asigned value increases not lineally but exponentially. The scale has no maximun or minimun values. In fact, technical development of seismographs have allowed to measure sismic movements of -1,5 degrees.

Actually, no one talks about earthquakes until 2 degrees are reached. Under this level there are 8.000 tremors registered every day, although they’re imperceptible. It’s only above 4 degrees that a tremor can be noticed, but it would be uncommon for a 4 degrees earthquake to cause significant damages. Damages appear starting from 5 degrees.

A 6 degrees earthquake might destroy a 160 km. diameter area. The 2009 tremor in L’Aquila (Italy), which was 6,9 in the scale, caused 294 deads and 50.000 people lost their houses.

The biggest earthquake ever measured in history took place in Valdivia (Chile), on May 22nd, 1960: 9,6 degrees in Richter scale. The land shaked for ten minutes, killing 3.000 people. The sea rised four meters in the harbour just before moving away, sweeping away all the ships, and returning as a 10 meters high tsunami that hit the coast villages at 150 km per hour. The shock wave covered the Pacific, causing seaquakes in Hawaii, which is 10.000 kilometres far from the epicenter. Effects of the Valdivia earthquake were noticed in Japan, Philipines, California, New Zealand, Samoa and the Marquise Islands.

The 10 degrees in Richter’s scale is the estimated measure for the impact of a meteorite with 2 kilometres in diameter at 25 km per hour. It’s just like placing the armaggedon in the scale.

Charles Francis Richter died in 1985. He probably never visited Haiti. Anyway, he couldn’t do it anymore. Because Haiti no longer exists: on January 12th, 2010, 7,3 points in the scale swallowed it.

Haiti from the sky

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