In Conversation
Understanding Disaster:
A conversation with Kevin Furlong
Geophysicist Kevin Furlong has spent the past 20 years studying plate tectonics and lithospheric geodynamics—the processes that drive earthquakes and related natural disasters. He has developed a series of courses that focus on the causes and consequences of these hazards, aimed at both general-education and upper-level students. He also directs the Natural Hazards Center at Penn State.
In answer to a recent Research/Penn State Probing Question, raised soon after the catastrophic Sumatra earthquake and tsunami of 2005, Furlong commented on the possibility of a giant tsunami striking the United States.
At the same time, he spoke with editor David Pacchioli about a communication disconnect between scientists and society that often exacerbates hazards, and stressed the need for improved education of both the public and disaster professionals in order to create a "thinking response" to natural disasters. Following is a transcript of their talk.
Kevin FurlongPhoto by James Collins
Q: How do we set priorities in preparing for natural disasters?
A: There's always a trade-off. We know now, for instance, that every few hundred years there's going to be a large-scale tsunami in the Pacific Northwest. And a lot of people live there. So it makes sense to spend the money to prepare for such an event and mitigate damage as much as possible.
Then there are events that will have smaller impact, but happen much more frequently. It makes sense to prepare for them, too.
If it's a really major event that's going to happen every thousand years, though, it becomes harder to justify the cost-benefit. Of course if such an event does occur there will be an outcry—For years the government has known about this hazard and done nothing about it. But where is the cut-off? What are we willing to pay for?
The other problem for dealing effectively with events that tend to happen on longer timescales is a lack of stamina. Since the tsunami just happened in Sumatra, it's easy to say we need to install better warning systems. But 10 years from now, when the equipment needs to be upgraded and maintained—it's sitting out in the Indian Ocean, there's going to be breakdowns, it's going to be very expensive—when the disaster fades from memory, does the society have the stamina to keep its guard up?
And then of course you could argue that hurricanes are a much bigger hazard than tsunamis. Devastating hurricanes hit the U.S. every 10-20 years.
Q: What makes predicting an event's impact so difficult?
A: Part of the problem is that these are very complex events, involving lots of factors working in combination. There's not enough appreciation of the complexity.
I was recently in New Zealand, and they were talking about the tsunami hazard there. They should have had a big tsunami from the great Chilean earthquake of 1960, the largest earthquake ever recorded. And in fact they did have a decent-sized tsunami, but it hit during low tide, so it did much less damage than it might have. The tidal range was several feet, and most of the tsunami's energy went into creating a high tide at the wrong time.
That's a kind of subtlety that the general public doesn't really appreciate. They assume, 'Oh, tsunamis arent too bad. The same is true of a hurricane. A storm is a complex engine. The storm surge can be bad or not so bad, depending on whether it hits during high tide or low tide, and whether it's a time of the cycle when the tides are bigger. These are second-order effects that can totally control how much devastation there is. You try to explain that to the general public and it gets really complicated. Even the 1960 earthquake only did a little bit of damage.'
Next page: "Did these secondary factors play a role in the response to Hurricane Katrina?"