Who’d want to be president? Every day the world serves up a new cocktail of misery, carnage and strife. And as president, it’ll be your responsibility. This week opens with a horrible massacre by a U.S. solider in Afghanistan, and now the Taliban is vowing revenge. Gas prices are spiking again and, guess what, Americans blame Obama. The Supreme Court may be about to stomp on his health care plan (what’s the Vegas line on Obamacare surviving?), and (per the NYTimes editorial board) he’s got to figure out what to do about this strategic nuclear arsenal in a world still armed to the teeth with nukes. (Pakistan has 90????)
So I guess no one wants to hear about earthquake hazards. You may have seen my story on seismic hazards that ran Saturday. Upshot: Lots of debate over whether the seismic hazard maps are that useful. My one nagging thought in all this is that I’m not sure we’ve ever adequately written about the possibility of a major East Coast earthquake. Sure, I’ve mentioned it in stories, and you may recall that we actually had a pretty big one last year, one that did considerable damage to the Washington Monument and the National Cathedral. That was a 5.8 magnitude quake on something I’d never previously heard of, “the Central Virginia Seismic Zone.” If I’m not mistaken, we don’t actually know, or understand, what causes these intra-plate earthquakes (this is nowhere near a tectonic plate boundary, such as the San Andreas Fault). Could there be a Big One out there that could hit the East Coast and knock down a whole bunch of brownstones and churches and other masonry structures that weren’t built with earthquakes in mind? I don’t think anyone knows the answer.
This morning I came across an interesting abstract for a talk coming up by a George Mason University professor, Richard Diecchio, next month in Asheville:
“The Richter scale is open-ended. The longer we measure earthquakes, the higher the magnitudes we observe. In 2011 alone, the 9.0 magnitude Japan earthquake, and the 5.8 magnitude Virginia earthquake were the worst recorded in their region. The highest magnitude earthquake recorded globally was a 9.5 in southern Chile in 1960. These are the worst we have measured, not the worst that have ever occurred.
“We do not know, and cannot predict the worst case scenario. We do not know what the highest possible magnitude earthquake is, globally or regionally. We know which areas are more prone to earthquakes of various magnitudes, but we do not know where or when an earthquake of any magnitude will occur. The problem is that the general public is not fully aware of the limits of our knowledge. When we engineer our cities and infrastructures, we engineer for the worst we have observed, or something less than that. With a false sense of security, we then rely on these structures, and build our communities accordingly. Then when a big earthquake hits, we are always caught off guard, and the disaster is worse because of structures and infrastructures we have created.”
Which echoes what our story said the other day.
What happened last March 11 wasn’t supposed to be possible. The seismic hazard maps didn’t entertain the idea of a 9.0 magnitude earthquake off the Tohoku coast of Japan.
But the Earth paid no heed to scientific orthodoxy. A massive slab of the planet’s crust lurched 180 feet to the east. It rose about 15 feet, lifted the ocean and tipped the Pacific’s waters onto the Japanese coast.
The quake and the resulting tsunami killed about 20,000 people, wiped out entire towns and triggered power outages and then meltdowns at the Fukushima nuclear power plant.
It also humbled the scientific community.
Since 2004, earthquake scientists have been caught off guard, or to some extent consternated, by huge killer earthquakes in the Indian Ocean, Haiti, China, Japan and New Zealand.
Now the geologists are in a state of soul-searching. They want to do better, get smarter and help save lives on a shaky planet. But they feel chastened by what happened in Japan and are reexamining their basic assumptions about earthquakes.
Humans can be gifted at perceiving patterns in nature. We can also imagine patterns that do not exist. We can focus our attention on too narrow a frame. It is the special challenge of earthquake scientists that they must contend with terrestrial forces that exist outside the frame of human lifetimes, or even the lifetimes of entire civilizations. Some geologic faults may endure thousands of years of strain before a catastrophic rupture.
“This is a humbling field. If you want to be smug, don’t be an Earth scientist, and certainly don’t be an earthquake researcher,” said Ross Stein of the U.S. Geological Survey.
Seismic hazard maps typically show where earthquakes are most likely to occur over a certain period of time, and the expected maximum intensity. But critics say these maps merely describe what has happened before and have virtually no predictive value. They call it “Texas sharpshooting” — shooting the side of a barn and then drawing a bull’s-eye around the bullet hole.
Defenders of the maps argue that they are better than nothing. Policymakers have to decide where to put resources. Which locations have older buildings that are most in need of seismic retrofitting? How high should a tsunami wall be?
Public officials may say, in effect, we know this map is probably wrong, but we still need it for planning purposes.