Do You Understand the Richter Scale?

Recently, Sarah Zhang, a science writer for Wired who calls California’s Bay Area home, had been wondering if the concept of earthquake magnitude—introduced by the development of the Richter scale in the 1930s—was still useful, and whether people understand what makes, say, a 4.0 magnitude earthquake different from a 6.0 one. A few days after her article “The Way We Measure Earthquakes is Stupid” came out, a magnitude 4.0 earthquake occurred near San Francisco on Monday, August 17, 2015.

Zhang isn’t alone in her ponderings. In 2000, Lucy Jones, a seismologist for the U.S. Geological Survey, published a piece called “True Confessions From a Magnitude-Weary Seismologist” in the journal Seismological Research Letters. She opened the letter with the following line: “I hate the Richter scale.” That distaste, she explained, was due in part to the fact that the public did not—and does not—understand quite what earthquake magnitude means. (The USGS, for example, no longer uses the Richter scale, but the moment magnitude scale.) Jones explains why the system might be confusing the public and failing to communicate essential information about earthquakes.

*This copy was updated on August 21st to reflect the following changes. Earlier copy stated that the recent earthquake in San Francisco occurred the day after Sarah Zhang’s article appeared, but it was a few days after. Also, earlier copy referred to the question of whether or not people understand the Richter scale, but that phrasing has been changed to whether or not they understand the concept of earthquake magnitude.