Richter Mortis

The decline and fall of the Richter scale

The recent earthquake in Southern California unearthed a reason to celebrate. Not because it wasn’t the Big One, or even the Pretty Big One, but because so few media outlets measured it on the Richter scale.

Charles F. Richter, a seismologist and physicist at Cal Tech, developed his eponymous scale in the 1930s along with Beno Gutenberg, who usually gets no credit for his role. They realized that the magnitude of an earthquake could be measured by comparing its amplitude—the waviness of its lines on a seismograph—with its distance from that seismograph. The resulting scale indicated how much energy the quake had released, and replaced the scale that measured how much damage a quake could do. Each increase in the Richter integer reflected a rise in the magnitude of the quake by an order of, well, magnitude, or multiplied by 10.

Use of the Richter scale caught on quickly, and it became one of those automatic phrases for journalists, like “software giant Microsoft” or “oil-rich Kuwait.” No earthquake story was complete without “the quake
measured X.X on the Richter scale.”

But measuring earthquakes is a science, after all, and the Richter scale was of limited use. The scale was originally intended to measure only California quakes, which are different from quakes in, say, China, or even Mexico, where the makeup of the Earth’s crust and what lies atop it can affect the magnitude of an earthquake. In 1979,
seismologists developed another way to measure earthquakes, called the moment magnitude. Considered much more accurate, the moment magnitude measures how much the earth actually moved. (It’s OK to simply say
“the earthquake had a magnitude of X.X” and abandon the moment.)

Old habits die hard, however, and it wasn’t until very recently that most American news wires and publications stopped automatically referring to the Richter scale. But non-American news outlets and television and radio have been slower to follow. A Nexis search shows that all but 100 or so of the thousands of uses of “Richter scale” in
the past two years are from Reuters, Agence France-Presse, and other non-American publications and wire services. But during the recent California quake, a lot of radio and TV outlets slipped a Richter into
their broadcasts, leaving seismologists and others who prefer precision quaking in their boots.
