Humankind has always been awed by the phenomenon of earthquakes. The earliest Greek philosophers speculated on their causes, and the Chinese scholar Zhang Heng (78-139) invented in 132 the first known means of measuring them. Likewise, the intensity of quakes (based on observations of their effects) has been quantified since the 19th century.

    But the first objective way to measure the magnitude of earthquakes was created in 1935, when Charles Francis Richter (1900-1985) and his colleague Beno Gutenberg developed the measurement known as the “Richter magnitude scale.” “Magnitude” is how much energy a quake produces at its source; “intensity” is the effect it has in a particular location.

    Charles Richter was born in Ohio but grew up in Los Angeles. He graduated from Stanford University in 1920, and later began studying for a PhD. in theoretical physics at the California Institute of Technology.

    Before graduating from Cal Tech, however, he accepted a teaching job at the Carnegie Institute of Washington, where he became interested in the study of earthquakes. He returned to California and began working at the Seismological Laboratory at Cal Tech, where he worked until retirement.

    The laboratory was studying Southern California’s frequent earthquakes. The scale named for Richter was actually developed by a collaboration between Richter and the German-born Beno Gutenberg. Gutenberg hated publicity, so the pair left his name off of their scale.

    The scale, based on a paper by the Japanese seismologist Kiyoo Wadati, measures the energy released in a quake. It uses logarithms in reporting. This means that a quake of, say, 6.0 on the Richter scale is 10 times stronger than a quake of 5.0, 100 times stronger than a 4.0, and so on.

    A newer scale called the “moment magnitude scale” replaced Richter’s in the 1970s, but the numbers it produces are similar. So, in everyday language, most people — including those in the media — still call the numbers used in reporting earthquake magnitude “the Richter scale.”

    Vocabulary

    Which word above means:

    1. the study of space and time without experimentation

    2. a doctor degree

    3. people (as a group)

    4. a person who studies earthquakes

    5. deeply impressed, inspired

    6. size

    7. person who studies

    8. thought about, guessed

    9. cooperation, working together

    10. expressed in numbers