Scara Richter. What is the Richter scale?

Scara Richter. What is the Richter scale?

Scara Richter a fost imaginată în 1935 de Charles Richter și Beno Gutenberg, de la California Institute of Technology, pentru a măsura puterea unui cutremur. Este o scară logaritmică, pentru că magnitudinea, după Richter, corespunde logaritmului măsurării amplitudinii undelor de volum (de tip P și S), la 100 km de epicentru și este este gradată de la 1 la 9. De obicei intensitatea cutremurelor nu se exprimă în numere întregi, ci în numere fracționare.

Wikipedia info: Scara de magnitudine Richter

Deoarece scara Richter este o scară logaritmică, o modificare de un grad pe scara Richter este corelată cu o modificare de 10 ori a amplitudinii undelor seismice și de aproximativ 30 de ori a energiei eliberată de cutremur.

What is the Richter scale?

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.

http://mishunderstanding.wordpress.com/2011/01/23/what-is-the-richter-scale/