Cascadia's Fault - Jerry Thompson [128]
“The ETS intervals are different in other places in the world,” said Rogers, adding another complication. In northern California the cycle is much shorter than in British Columbia. In Oregon it’s longer. “So that’s something we don’t understand,” he said. “Why is it different from one subduction zone to another?”
With the setbacks at Parkfield still fresh in everyone’s mind, it seemed to me unlikely that many of the skeptics would change their opinions and agree that quakes do come in time-dependent cycles. The discovery of ETS, though, did inject new energy into the prediction quest. Just when chaos theory seemed to have won the day, there was a fresh reason to think that at least some seismic shocks might not be a statistical crapshoot.
Garry Rogers was cautiously optimistic when I asked whether earthquake prediction had a future. He hesitated a moment, choosing his words carefully. “Under certain circumstances—yes,” he said. “I think maybe Cascadia, maybe specific faults like the San Andreas that are very seriously studied, or specific faults in China—yes. I think I’m optimistic that that will happen. I’m not optimistic that we’re going to be able to predict earthquakes everywhere. And I’m not optimistic that any of the predictions are going to happen soon.” He smiled as I winced at all of the qualifications to his optimism. “So that’s a qualified yes, if you like. We just don’t know enough. It’s a really tough problem.”
Chris Goldfinger made a point of putting the Parkfield setback into a larger context. “Forecasting and prediction were words that were in great disfavor in the past couple of decades, partly based on the great Parkfield experiment,” he said. “It wasn’t really a failure—I don’t think—at all. People expected too much from a one-shot experiment like that. And so for decades, prediction became the ‘P-word’ and nobody used that word at all. But now, science is marching on. And we’re seeing things like ETS events, we’re seeing things like turbidite evidence for clustering [of Cascadia’s earthquakes over time], and the [possible triggering] relationship to the San Andreas. People around the world are seeing other, similar kinds of relationships. And while it’s far from prediction, it’s progress.”
“It may be that we never get to the ‘You’re gonna have an earthquake next Thursday’ sort of scenario,” added Goldfinger. “But I think it’s entirely possible that we’ll get to a point where we can say, ‘Sometime in the next decade we’re highly likely to have something happen.’ And I think that sort of thing is on the horizon, in the not-too-distant future.”
Lori Dengler at Humboldt State, who began her career as a prediction optimist working initially with William Bakun and Allen Lindh on the Parkfield experiment, eventually lost her enthusiasm for trying to read seismic tea leaves. In her opinion building stronger buildings and making communities more resilient should be the higher priorities. As for the current ability to forecast Cascadia’s inevitable failure, she said, “Well, I’ll tell you something I’m absolutely sure about. The next Cascadia earthquake is one day closer today than it was yesterday.”
Put the question a different way and you face another quandary. What if we did achieve a breakthrough in the science? What if the experts had another success like Haicheng and then became courageous, or foolhardy, enough to issue a prediction for Cascadia or the San Andreas? Would politicians and public officials know what to do with the information? Imagine you are the mayor, the police chief, the premier of British Columbia or the governor of Washington, Oregon, or California and the scientists come to your office early one morning and say, pretty much as Cao Xianqing did, “We think a major earthquake will happen today or this evening.” How would you respond? What would you do?
“Some people would question that if you have a prediction—if it’s not accurate enough—that you may cause more disturbance