How are Richter numbers determined for earthquakes that occurred prior to that time?
Dec 06, 2009
in
Earthquake Questions
The Richter scale was developed in the 1930′s.
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2 comments
A.Ganapathy India on December 6, 2009 at 2:00 am
Richter scale gives you the energy released during earthquake from the point of its origin namely focus point.It needs the seismograph picture to calculate the magnitude. The highest amplitude and the distance calculated by the arrival time difference has got some relation with Richter scale. Mr Charles Richter found a calculation method by using these data’s to decide the magnitude in the year 1935. It was used for only local earthquakes.Later on after we developed high Precision broad band seismograph we are able to measure even from a distance of 11000 k/m.The ancient seismograph first developed was having a ball with pin hanging above a fine sand spread ed at a table.The mark was used to find only the strength. There is another Mercali scale that directly gives you the effect of earthquake.No need for measuring instruments.Only the people and news paper reports were used to find in Mercali scale. To gain full knowledge visit this Web site.www.disasterreseachfoundations.com
Randy F on December 6, 2009 at 2:00 am
they are bases on the amount of damage done to buildings