Waiting for the big one: Is New York prepared for earthquakes?

Chimneys and balconies fall off buildings, blocking streets to traffic. Failed signals trap thousands of people underground in subways. Fires break out from damaged electrical wires.

That could well be the scenario should a big earthquake jolt New York City.

The possibility exists that a considerable quake will rattle the nation's most populous city within the next few decades, seismologists say. The metropolis lies on several faults, along which tremors tend to occur. While most New Yorkers are probably blissfully unaware of the potential hazard, city planners are preparing for the worst, but experts warn that they may not be doing enough.

The city has yet to look at the impact an earthquake would have on infrastructure like sewers, subways and airports, warns Klaus Jacob, a seismologist at Columbia University's Lamont-Doherty Earth Observatory in Palisades, N.Y. "There's still a big gap in our knowledge," he says.

The last big earthquake rattled New York in 1884, with an epicenter in the Atlantic Ocean south of Far Rockaway in Queens. Before that, a large tremor occurred around the same spot in 1737.

Both quakes measured around magnitude 5, which scientists say can cause significant damage. By comparison, the quake that generated the recent Asian tsunami measured 9.0 and the California earthquake of 2003 was 6.5. The latter killed two people, left 100 families homeless and caused $100 million in damage.

In the event that New York experiences an earthquake of magnitude 5, Jacob estimates that material and business losses could total up to $5 billion.

A recent U.N. conference in Japan noted how mega-cities like New York were vulnerable to disasters because of their dense populations. The city's own Office of Emergency Management's Hazards Overview notes that skyscrapers, the subway system, road tunnels and bridges could be affected. "People may be trapped in such structures or stranded geographically due to such disruptions," the overview says.

An earthquake along the East Coast could wreak damage over a greater area than one of similar magnitude along the West Coast, says David Russ of the U.S. Geological Service in Reston, Va. Because the earth's crust is colder and more brittle on the East Coast, seismic energy transmits more efficiently.

Bearing this threat in mind, in 1998 a group of seismologists, emergency planners, engineers and city authorities formed the New York City Area Consortium for Earthquake Loss Mitigation. They prepared a detailed inventory that mapped out the potential damage to buildings in lower and mid-Manhattan by examining the engineering and the soil on which they stood. Response teams working in the World Trade Center area after the Sept. 11 attacks used the study to determine which buildings should be inspected.

A similar inventory for the rest of the New York metropolitan area will be ready this April, says Bruce Swiren of the Federal Emergency Management Authority (FEMA) and a member of the consortium. Emergency planners will then have an idea of problematic neighborhoods so that they can plan accordingly and be prepared if a quake happens.

Although no one knows for sure if a big quake is going to happen soon, smaller quakes have shaken the city recently. In 2001, tremors measuring 2.4 and 2.6 hit Manhattan, but no structures were affected. To be prepared for larger quakes, all buildings over four stories built since 1996 have had to comply with a seismic code prepared by the city’s Department of Buildings to reduce their vulnerability.

The U.N. conference concluded that a "culture of disaster prevention and resilience" had to be fostered. City emergency planners, the Red Cross and even wireless phone companies have prepared guidelines for what people should do, from securing bookshelves to readying bags of essential supplies. But these instructions do not seem to have trickled down to the average city inhabitant, experts warn.

"Do people know what they should do?" asks Dr. Irwin Redlener of the National Center for Disaster Preparedness at Columbia University's Earth Institute. He believes that planners can't judge the impact of such guidelines on ordinary people. "There needs to be more study on that," he says.

Adding to worries are possible tsunamis. Although New York City is unlikely to suffer the devastation that recently swept regions in Asia, John Mutter of Columbia's Earth Institute said a tsunami could occur here. "To say it could not happen is not true," he told a gathering in Manhattan in late January that discussed how science could help avoid another tragedy.

However dire the worst-case scenario, New York has a low earthquake risk, according to AIR Worldwide, a catastrophe risk analysis firm in Boston.

FEMA's Swiren feels that New York isn't quite ready, but that it's getting there. He observes that just 15 years ago, the city was at an equally early stage for hurricane planning. Now, authorities have readied detailed maps and instructions for evacuating low-lying areas in the event of a hurricane.

"It's a drop in the bucket, but if an earthquake were to happen next week, we'll be screwed," he says. But "starting now is a lot better than starting 15 to 20 years from now."