The Richter scale is a logarithmic scale used to express the total amount of energy released by an earthquake. Its values typically fall between 0 and 9, with each increase of 1 representing a 10-fold increase in energy.

Wikipedia info:  http://en.wikipedia.org/wiki/Richter_magnitude_scale

 

Size and Frequency of Occurrence.

There are around 500,000 earthquakes each year. About 100,000 of these can actually be felt.  Minor earthquakes occur nearly constantly around the world in places like California and Alaska in the U.S., 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, the relationship being exponential; for example, roughly ten times as many earthquakes larger than magnitude 4 occur in a particular time period than earthquakes larger than magnitude 5. In the (low seismicity) United Kingdom, for example, 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. This is an example of the Gutenberg-Richter law.

 

 

RECENT EARTHQUAKE HISTORY:

Thank you to Liz for this one. Here’s a link to a website that hosts data of all the earthquakes globally over the last seven days:  http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/quakes_all.php

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