The Richter scale has been around for over 70 years, but unless youre among those who live in an earthquake prone area, you may not have a full understanding of the differences between earthquakes with similar scale values.Charles F. Richters Logarithm
In 1935, Charles F. Richter, of the California Institute of Technology, developed a logarithm to accurately determine the size of earthquakes based on the amplitude of waves recorded on seismograph instruments. This logarithm, used by the United States Geological Survey, became known as the Richter Magnitude Scale.
This scale isnt an actual device, but is instead a mathematical formula for calculating the size of an earthquake based on seismograph readings taken during the event. Starting at zero, the scale theoretically has no upper limit, although to date the strongest earthquake ever recorded, the May 22, 1960 quake off the coast of Chile, South America, measured a 9.5.
But because of its order of magnitude style of sizing, many people may not comprehend just how much a small increase in measured size matters.
What is an Order of Magnitude?
Put simply, an order of magnitude in this case refers to a tenfold increase. In other words, each whole number on the Richter Scale represents an increase of ten times in amplitude strength. For example, a 6.0 earthquake is ten times stronger than a 5.0. Or, to use a real world example, the 1989 Loma Prieta earthquake that devastated the San Francisco Bay area, measured at 7.1 on the Richter Scale, was over a hundred times smaller in intensity than the 1960 Chile earthquake mentioned above.
Bear in mind also that these numbers represent an increase in the earthquakes amplitude, not energy released. To calculate the amount of energy released using this scale, the magnitude increase is equal to roughly thirty-one times for each whole number on it.
In other words, a 6.0 earthquake releases thirty-one times the energy of a 5.0 earthquake. To put this in perspective, the 1960 Chile, South America 9.5 earthquake released well over nine hundred times more energy than the 1989 Loma Prieta 7.1 earthquake!
Are We Suffering from Information Overload?
Earthquakes happen almost constantly. There are literally thousands recorded each year, and on average, there will be at least one 8.0 or higher quake per year. In decades past, we were blissfully unaware of most of these, unless they occurred in a highly visible part of the world. But with todays constant barrage of twenty-four hour news channels, there seems to be a major earthquake story in the headlines almost every week.
In fact, according to the United States Geological Surveys website, there have been at least seven earthquakes measuring 7.0 or greater in the first 70 days of 2011, including the tsunami generating quake that hit off the coast of Japan on March 11, 2011. With all the accompanying news coverage, it would be easy for people to begin tuning out the information, and not fully comprehend the major differences between these natural disasters, especially if they dont fully comprehend the Richter Magnitude Scale.