Along civilisational fault lines

I used to be a science writer, where I learned to think of the ground beneath my feet as something alive. It crawled and shivered, stretched and quaked. In California — as opposed to the relatively placid terrain of Wisconsin, where I now live — it’s impossible to miss that reality. The great San Andreas fault, where the Pacific and North American plates meet, slowly rumbles its way along the western edge of the state. The fault slides and catches, builds up pressure and then releases that pressure along smaller adjacent faults.

At one meeting of seismologists I attended, the organisers strung a banner across the front of the conference room with a quotation attributed to the historian Will Durant: “Civilisation exists by geological consent, subject to change without notice.” I’ve always liked that line — its rebuttal of our natural hubris, our assumption that we inevitably lord over this small sphere in one of our galaxy’s lesser solar systems.
Surely, you think, we should be able to rely on rock. A country like Haiti, already battered enough by circumstance, should be able to find safety in solid ground. Somehow it should be so, even though our planet proves that wrong again and again. Remember the 2008 earthquake in Sichuan Province in China, which left more than 88,000 people dead or missing? The Indonesian earthquake of 2006, which killed more than 6,000 people?

Haiti is situated along a strike-slip fault between two great plates of the earth’s crust, just like the San Andreas of California. The word fault does not imply a mistake. Nor does it suggest a stationary crack in the earth’s crust. In geology, the word “fault” implies motion.  Beneath the thin outer skin on which we stake our lives, our planet flexes its muscles. The hot magma that lies below, the liquid minerals and metals that swirl around the earth’s core, conspire to keep the surface moving. The crustal plates, which cover the planet’s surface like a great rocky jigsaw puzzle, push against, under and over one another. All with the slowness, and the inevitability, of geologic time.

The great continental and oceanic plates of crust are always moving, rubbing, rearranging the bedrock of our lives. The motion is too slow to catch our attention except when it becomes erratic. Strike-slip faults tend to get stuck as they slide against each other, one jagged section catching on another.

They grind slowly onward though, moved relentlessly by that underground current, eventually breaking the hold, setting off the reverberations of a quake. It’s been more than 100 years since the San Andreas broke in a spectacular way, more than 200 since the Enriquillo-Plantain Garden Fault, the one adjacent to Haiti, did so. It takes time for even the earth to build up to a catastrophe. Although we have used that time to learn the mechanics of earthquakes, we are still a long way from being able to predict them.