Sunday, October 1, 2017

New York City is overdue for a major earthquake

Kathryn Miles
For a city that seems to move at the speed of light, being late is never a good thing. That’s true for budget agreements, that’s true for commuter trains, and as it turns out, it’s probably true for earthquakes as well.
We tend to think of seismic activity as a West Coast problem. Friday demonstrated all too well what a magnitude-8.2 earthquake can do to Mexico and Central America; many of us remember the World Series quake that rocked the San Francisco area in 1989. But New York, which is actually riddled with faults, has a long history of earthquakes: On average, the region has witnessed a moderate quake (about a 5.0 on the Richter scale) every hundred years. The last one was in 1884. Seismologists say we can expect the next one any day now.
Admittedly, a moderate quake isn’t going to cause Hollywood-level destruction, nor is it going to raze Manhattan. But it is going to do plenty of damage: upwards of $39 billion in losses and over 30 million tons of debris. That rubble, caused largely by crumbled brick and stone buildings, is going to clog already congested roads, making it impossible for first responders and public transportation to move about the city.
It may be equally difficult to travel below ground in some cases. Take the Steinway Tunnel, a 1.3-mile cast-iron tube that runs deep below the East River. The 7 train passes through it every 20 minutes, often packed with commuters or, this time of year, Mets fans. Construction on the tunnel began around the time of the last earthquake, long before seismic codes or even modern engineering practices had been codified. As a result, there are big craters and gaps where the tunnel lining isn’t actually in contact with the earth around it. In the event of a quake, that’s going to cause the tunnel to rattle around. And because the tunnel runs through both the soft mud of the riverbed and the hard bedrock on either side, different segments are going to rattle around at different speeds and frequencies. That’s doubly bad news for cast iron that was never in very good shape to begin with.
 New York is vivisected by faults. Most of them fall into two groups — those running northeast and those running northwest.Mike Guillen
There are more than a dozen tunnels like the Steinway connecting Manhattan to New Jersey and Long Island. They’re all at risk of serious damage in the event of a quake. Just how much of a risk we can’t say, because little has been done to evaluate their seismic soundness. Vince Tirolo, a longtime engineer for the Metropolitan Transit Authority who now serves as a private consultant and adjunct professor at Columbia University, has been sounding the alarm about these tunnels for years. He says he hasn’t received much of a response from the city. As research for my book, “Quakeland,” I contacted the MTA to ask for an interview with the person handling their emergency management and seismic assessment. I wanted to know why more wasn’t being done to fix these beleaguered tunnels or to assess their risk in the event of an earthquake. They told me they couldn’t accommodate my request. I asked why. Nine months later, I’m still waiting for a response.

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