The 8.9 magnitude earthquake off the coast of Japan was a devastating event and did unknown amounts of damage. There is risk of fire, water shortages, power outages and radiation leaks, not to mention 1,000 dead. (To separate mass media hype from fact, see Patrick Lockerby's comprehensive and frequently updated Japan's Nuclear Emergency - The Straight Goods and also Japan Quake - Media Up To Mischief)
In the context of all that it may seem cavalier to state that if it has to happen, at least it happened in Japan, but that's the case; it is impossible to gauge how many lives were saved because it happened there and they can be a model in the future for any country at risk for this kind of earthquake, including the U.S.
Compare 1,000 dead in Japan Friday to the 9.1 earthquake (and also a resulting tsunami) that hit the Pacific in 2004. Death toll then: 400,000. In that light, the events in Japan are a testament to preparedness. The Japanese are no strangers to earthquakes and water disasters but it still takes more than awareness, it takes science and planning and money to keep disasters from wiping out tens or hundreds of thousands of people.
First, what does that 8.9 magnitude earthquake really mean? The Richter Scale, whose numbers are commonly associated with earthquakes, was developed in 1935 by two gentlemen from Caltech, inspired by a similar scale, apparent magnitude, in astronomy. They used seismograms and established that a magnitude 0 event would an earthquake that would show a horizontal displacement of 0.00004 inches on a seismograph 100 km from the earthquake epicenter.
The actual Richter scale uses the logarithm of the amplitude of waves so each whole number increase in magnitude is a 10X increase in measured amplitude; in energy terms, a whole number increase is an increase of about 31X the amount of energy released.
There are 1,000 earthquakes each day below 3 but earthquakes like occurred recently happen rarely.
To put that 8.9 in context, the atomic bomb that hit Nagasaki during World War II had the energy of a 5.0 earthquake on the Richter scale. The San Francisco Bay earthquake was a 6.9 while the Valdivia earthquake that hit Chile in 1960 was 9.5. No one can say for sure but the projections are that the event that created the Chicxulub crater was a 12.5. That is a lot of energy for engineers to resolve with superstructures and building design. But they did. And they're still resolving damage, since geologists say there have been 27 aftershocks magnitude 6 or greater and 154 over 5. Incredible!
Geologists don't use the Richter scale these days. As scientists learned more they discovered better ways to measure earthquakes and engineers discovered better ways to mitigate their effects. The earthquake on Friday moved the entire island of Honshu 8 feet to the east. It took resolve long before this happened, and with no guarantee it would ever happen, to make sure it wasn't much worse. This is a lesson for everyone to keep in mind when people are discussing policy issues and the planet we live on.
What would have happened in a country less prepared; a complete cataclysm. While countries mobilize to help Japan recover we can also give a little thanks for showing us how to be prepared.
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- The Law has Failed, Not Forensic Science
- Women With Endometriosis Need More Support, Less Judgment
- Olive Oil Destroys Cancer Cells
- Recent Results From Super-Kamiokande
- 'Just Say No' To Behavior-Calming Drugs For Alzheimer Patients
- The Real Meaning Of The Blue Black White Gold Dress
- Francis Halzen On Cosmogenic Neutrinos
- "Thank you John, sorry to hear that your father had ALS, its amazing how common these neurodegenerative..."
- "Perhaps a wee bit out there, but looks almost like some high velocity impact craters of metal-packed..."
- "This seems like more of an unfortunate case of looking for a headline, and speculating about climate..."
- "John Collins comment about academia criticizing forensic science to get grant money is accurate..."
- "Hi, I suppose they will be soon available in the conference web site, at https://agenda.infn..."