New Madrid Earthquake and the Richter Scale?
Jan 28, 2010
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Earthquake Questions
The mega earthquakes in New Madrid on December 16, 1811 and January 23 1812 were quite strong I understand. However the earthquake that struck the New Madrid fault Zone on Feb 7, 1812 is said to have reached 8.0 on the Richter Scale. How is this possible when Charles Richter’s Richter scale was not invented for another hundred years?
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3 comments
Wayner on January 28, 2010 at 9:24 am
By comparing the types of and extent of damage to similar structures for earthquakes in which there is a Richter magnitude.
A.Ganapathy India on January 28, 2010 at 9:24 am
You are correct. The Richter scale is using the maximum amplitude recorded at any place and the distance to calculate the Richter scale.He has invented a method by which the energy released at the point of focus can be decided.This is what the concept of Richter scale.He has formulated this method in the year 1935 when he was in Pasadena university. But the simple seismograph required for this cal calculation purpose was invented long back.Using those data’s they should have calculated only after 1935.
Sieran Vale on March 1, 2010 at 1:41 pm
Earthquakes have been measured with amazing accuracy since the the late 1600s, using several different scales including The Rossi-Forel Scale and later the Mercalli Intensity Scale which took over in 1884. (it was perfected, renamed the MMIS — modified Mercalli intensity scale – and made sort of the international standard in 1902, just prior to the San Francisco quake.
Later, the MCS Scale took over, followed by the MWN Scale – which was the scale slightly modified by Charles Richter. Technically, world governments no longer even use the Richter Scale – we’re all hooked into the MMS (Moment Magnitude Scale) but we still call it the Richter Scale the way people call tissue “Kleenex” even though it isn’t.
Scientists are confident they have correctly transposed the measurements of ALL of the major earthquakes on the “world list” into “Richter Scale” numbers. None of the earthquakes which are officially considered for inclusion occurred before 1700 – because they would have been considered as “predating earthquake measuring equipment.”
New Madrid was HUGE for the massive AREA IN SQUARE MILES it damaged between the original quake and uncountable aftershocks — some of which were as intense as the original itself.
The strongest of the New Madrid earthquakes (it was a series that occurred between 12/16/1811 and 2/7/1812) is officially estimated as having been 8.1 (the first of them – Dec. 16, 1811 at 2:15 am.) The three following earthquakes (which we now realize were aftershocks) were all between 7.2 and 8.1. Not large enough to qualify for the “TOP 18.” Last week’s quake off the coast of Santiago was, though — it came in as NUMBER EIGHT and EIGHT POINT EIGHT.
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