Whenever news of an earthquake hits, we are told that the quake had a magnitude of, say, 3.2 or 5.0. Or 7.0, as was the case yesterday in Haiti and use retin-a. We all understand that 7 is worse than 5, of course, but I fear that few of us really understand or appreciate the degree of that difference.
Popularly (but inacurately) called the Richter scale, today’s seismologists measure an earthquake’s energy according to what is technically called the moment magnitude scale.
The magnitude scale is logarithmic: Each increase in the magnitude number actually represents more than 30 times the magnitude of energy released. A 7.0 magnitude quake is 32 megatons of seismic energy, where a 6.0 is only 1 megaton of seismic energy.
I imagine Mr. Richter and his successors prefer to use such a logarithmic scale because it permits them to communicate a quake’s magnitude extremely efficiently. They’re mathematicians, they intuitively understand that 5.4 is actually 5 times bigger than 5.0.
But for the rest of us, even those of us who are numerically literate, the logarithmic scale isn’t something we use every day. To most of us, 5.4 is only a little more than 5. Indeed, 7 isn’t that much more than 5 for us, either — yet in earthquake terms, 7.0 is one thousand times as destructive as 5.0.
I appreciate that the media thinks enough of us, the public, to report using the same technical jargon that scientists use. But in this case, I suspect they are doing the public — and the victims — a disservice. What if, instead of simply calling Haiti the victim of a “7.0 earthquake”, they called it a “32 megaton earthquake”? Or a “32,000 kiloton earthquake”? This would permit people who understand what a 4.0 earthquake feels like (and lots of people do understand this) understand that Haiti is today the victim of an experience thirty-two thousand times worse.
Some ideas on how to help the victims in Haiti: