An earthquake strength scale for the media and the public

Earthquakes & Volcanoes (USGS)


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Let's face it: seismologists do a pretty poor job of communicating the facts about our science to the public. Earthquake magnitude is the classic example. How many of us have struggled to explain the Richter scale? We explain that it is logarithmic, with each unit indicating a factor of 10 increase, but this really represents a factor of 32 increase in intrinsic earthquake size, and in any case we don't use the Richter scale anymore. By then the unfortunate listener is reeling and can be dispatched quietly by mentioning negative magnitudes or saturation. We even wonder why the audience or the reporter has this glazed look when we we finish.

A local engineer, E.P Hailey, pointed this problem out to me shortly after the Loma Prieta earthquake. He felt that three problems limited the usefulness of magnitude in describing an earthquake to the public; (1) most people don't understand that it is not a linear scale; (2) of those who do realized the scale is not linear, very few understand the difference of a factor of ten in ground motion and 32 in energy release between points on the scale; and (3) even those who understand the first two points have trouble putting a given magnitude value into terms they can relate to. In summary, Mr. Hailey wondered why seismologists can't come up with an earthquake scale that doesn't confuse everyone and that conveys a sense of true relative size. Here, then, is m attempt to construct such a scale. 

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title An earthquake strength scale for the media and the public
Series title Earthquakes & Volcanoes (USGS)
Volume 22
Issue 5
Year Published 1990
Language English
Publisher U.S Geological Survey
Description 3 p.
First page 214
Last page 216
Online Only (Y/N) N
Additional Online Files (Y/N) N