Bengaluru, April 27: Aftershocks, including a 6.7-magnitude one in Nepal, continued to rock the Himalayan nation and India even a day after a devastating quake killed over 3,400 people in the two South Asian neighbours. [Follow updates on Nepal earthquake: Day 3]
But a big coincidence in this earthquake episode is that it took place on the 115th birth anniversary of Charles Francis Richter, the American seismologist and physicist famous for making the magnitude scale quantifies the size of earthquakes. It was succeeded by the moment magnitude scale in the late 1970s. [Earthquake: IAF fetches nearly 2,000 Indians back from Nepal]
Richter, who was born in Ohio in the USA on April 26, 1900, was inspired by Japanese seismologist Kiyoo Wadati paper on shallow and deep earthquakes published in 1928. Richter first used the scale in 1935 after developing it in collaboration with Beno Gutenberg, a German-American seismologist. [What Nepal needs at this time of crisis]
Richter was very young when his parents got divorced and he grew up with his maternal grandfather. He attended Stanford University and thereafter, he grew a fascination for seismology and worked at the new Seismological Laboratory in Pasadena, under Gutenberg's direction. Richter died at Pasadena in USA on Sptember 30, 1985.
Before Richter Scale came into being:
Before the Richter Scale came into being, earthquakes were recorded by a scale which was developed in 1902 by Italian priest and geologist Guiseppe Mercalli. His scale used Roman numerals to measure the intensity of quakes and classified them on a scale between I to XII, depending on how people and objects responded to tremors. If things swung, then the quake was classified as one between I-II while it was counted as X if buildings were destroyed. But the measurement was too subjective.
Richter Scale was more absolute:
Richter used a seismograph, featuring a long unwinding roll of paper fixed to a place and a pendulum or magnet suspended with a marking object above the paper roll. While measuring the earthquake, the scale measured the instrument's distance from the epicentre or the point on the ground located directly above the quake's origin.
Gutenberg suggested the scale to be logarithmic so that the actual earthquake size could be measured in terms of numbers.
The Richter scale was published in 1935 and it became became the standard measurement procedure for earthquake intensity.