Watching the ongoing devastation of the 7.0-magnitude earthquake that hit Haiti two weeks ago — observed by most Richmonders from the remoteness and safety of their living rooms — one of the inevitable questions that recurs is: Could it happen to us?
Theoretically, we know that it could. But how at risk are we?
In his recently published book, “Mega Disasters: Preventing the Next Catastrophe,” Florin Diacu, a mathematics professor at the University of Victoria in British Columbia, Canada, takes on hurricanes, volcanic eruptions, earthquakes, tsunamis, asteroid impacts, virus pandemics and economic meltdowns — all with an eye toward explaining the mathematical tools that help scientists better predict such catastrophic tragedies.
Mathematics may seem to be a science of precision with right and wrong answers, but for Diacu, chaos is something of a specialty and tells us about unpredictable natural disasters.
Mathematically defined, chaos refers to a series of changes that increase in frequency and magnitude, leading to heightened instability over time. As it turns out, “many of the megadisasters that happen can be modeled in terms of differential equations,” Diacu says. “Not all of them, but many of them.”
According to Diacu, more predictable disasters include hurricanes, for which measuring technology is highly advanced. Asteroid and comet movements, the paths of which have been documented for years and move in the vacuum of outer space, can be modeled with great precision. And in predicting volcanic eruptions, Diacu says, “we're doing pretty well.”
Less predictable disasters are earthquakes, disease pandemics and financial meltdowns, he says, because they involve more complex systems and, for varying reasons, are more difficult to measure using existing models.
Diacu says earthquakes are particularly problematic to predict — despite advanced seismic technology and constant monitoring by the U.S. Geological Survey. That's because it's impossible, at least now, for seismologists to know the exact below-ground locations of the Earth's tectonic plates. “You cannot reach that deep,” Diacu says. “The deepest hole ever drilled is about 7.6 miles, and it took 25 years to do it.”
The points at which the Earth's plates meet, by comparison, range between 10 and 40 miles below the surface. “So drilling is obviously not the solution,” Diacu says. Instead, seismologists must wait until an earthquake occurs to study how the waves propagate — and, by extension, where they're coming from. Even aftershocks and foreshocks cannot predict general patterns, Diacu says.
Beyond physical limitations, predicting an earthquake also is a question of probability — another mathematical concept that resists easy answers. Or not: “The risk is always there,” Diacu says. Compare a 2008 warning by American seismologists that a magnitude 7.2 earthquake could hit the Haiti region with the many predictions through the years of an explosive earthquake at California's San Andreas Fault.
How to know when, and for sure?
“The highest probability for an earthquake to happen is right now,” Diacu says. “So of course right now is every moment.”
The quirks of probability aside, how wary should Richmonders be of natural disasters striking Virginia? “Well … you know it's a small state,” the professor demurs. “I couldn't really pick something characteristic for it.”
There is one thing: “A hurricane can hit you very well,” he says.
Of course, asteroids could impact everyone. Diacu says that scientists identify between 1,000 and 1,200 asteroids, ranging in size from about a half a mile to a mile in diameter, as rogue objects that could collide with Earth at some point. But worldwide observatories possess the mathematic ability to predict very precisely the paths of such asteroids years in advance, and there are developing technologies that could divert flying rocks from outer space, Diacu says: “We stand a pretty good chance of overcoming such a megadisaster.”
Still, there are always other cosmic possibilities. “There could be an explosion of a supernova and the radiation would kill us,” Diacu muses. “But that's unlikely to happen.”