By Dr. Robert Thorson
The great earthquake that struck coastal Chile on Feb. 27 is becoming old news, at least for those not directly affected. With the immediacy of human suffering and the blitz of disaster recovery fading, the time has come to draw an important lesson.
Earthquakes are an epiphenomenon. If epicenter can be part of the earthquake lexicon, why not the word epiphenomenon: something above something else that accompanies it?
I ask that you to stay with me through a wonderful – thought slightly off-putting – analogy that will help you see why earthquakes constitute the downside of something we should be thankful for. I mean no disrespect to anyone still coping with the tragedy.
Etymologically, the word fart comes from the Middle English farten, which means to break wind. Physiologically, it’s the acute release of gas pressure that builds within the colon as the inevitable byproduct of digestion, the chemical reactions we use to draw energy from food.
As with earthquakes, we can make general predictions about the phenomenon in terms of magnitude and recurrence, but the size and timing of each specific event are random, especially when we’re asleep. Ecologically, farts are an important part of the cycling of matter and energy on which all of life depends, in this case nitrogen, hydrogen, oxygen, carbon dioxide and methane gas.
Only sociologically does farting become negative. This is mostly because the release of gas is often accompanied by harmless, but foul-smelling byproducts of digestion, especially the rotten egg odor of hydrogen sulfide.
A person who doesn’t fart is a dead person. They’ve stopped recycling earth materials via digestion. Likewise, a planet that doesn’t quake is a dead planet. It’s stopped recycling solids, liquids and gases via tectonic activity, as with Earth’s moon.
Geographically, without plate motion, there would be no continents on which animals and plants could live, and no oceans for marine life. Indeed, without the sinking of the Nazca Plate beneath the South American Plate, there would be neither uplift nor volcanism, hence no Andes Mountains. Climatically, there would be no rainfall, snow or runoff. Politically, there would be no nation of Chile.
Deep within the Earth, plate motion is slow, continuous and vibration-free because the materials are warmer, and therefore softer. Near the surface, however, the buildup of stress within the upper crust takes place within cooler, stronger, more brittle materials, which flex and compress until the juggernaut of strain reaches the breaking point.
In Chile, most of the large ruptures take place offshore. Radiating from each like sound from an explosion is the seismic energy responsible for creating the chaotic combination of high-frequency vibration, irregular ground motions and the sounds that speakers of Spanish call “el terremoto.” Ruptures also allow large volumes of the earth’s crust to shift beneath liquid water, creating large surface waves called tsunamis.
Earthquakes don’t cause tsunamis. Rather, the two are separate epiphenomena caused by plate rupture, a manifestation of our planet being alive. Similarly, the smell of a fart doesn’t cause its noise. Rather, the two are separate epiphenomena caused by the escape of gas, a manifestation of us being alive.
I didn’t write this column to be funny, or because I have nothing else to say about Chilean tectonics. I do so because understanding this root cause is a critical step toward mitigating inevitable losses.
Personally, I care greatly about Chilean earthquakes, having spent much of 1999 working on its seismic hazard mitigation as a Fulbright scholar to El Servicio Nacional de Geologia y Mineria, and as Profesor Visitante de Obras Civiles en La Universidad Tecnica Federico de Santa Maria, in Valparaiso, where my family experienced several earthquakes and lived where buildings are now destroyed.
We also visited one of my friends in Valdivia, where the greatest earthquake on earth took place in 1960. When there, I stood on the shore, looked out over the Pacific, and let myself be amazed at our living planet.