Could Boston Face A Natural Disaster Like Japan's?

BOSTON — When you see the scale of the devastation caused by the massive earthquake and tsunami that hit Japan last week, it's hard not to wonder if that kind of natural disaster could happen here in the Northeast.

There actually is a history of earthquakes in this part of the country, even though those quakes haven't been as damaging as the one in Japan, or as the ones that sometimes hit the West Coast.

To find out more about Boston's risk level, WBUR's All Things Considered host Sacha Pfeiffer spoke with Dr. Uri ten Brink, a geophysicist with the U.S. Geological Survey in Woods Hole.

SACHA PFEIFFER: There actually has been seismic activity in the Greater Boston area in the past. Where and when has that seismic activity been?

DR. URI TEN BRINK: There has been seismic activity since Colonial time in the 1600s, probably around Cape Anne. And we only know that because most of the damage was in that area, but it was felt in a much larger area around the Boston area.

So that was 400 years ago. Has that seismic activity been relatively quiet ever since then?

In that area, yes. But a little bit farther north toward Vermont and north of the Canadian border there has been a lot more activity.

I grew up in Ohio and I recall once feeling a tremor when I was a kid. But I have never felt a tremor in Boston and I've lived here for 20 years. Do we get tremors and I've just missed them?

In the Boston area itself, as far as I can tell, we don't have many tremors. But we have a few tremors sometimes a little bit further offshore; they have been off the Cape, and they have been further south toward New York.

So if there has been seismic activity in the Boston area, but it goes back several hundred years, which is a long time ago in terms of our lifetimes, what's the likelihood that there actually could be an earthquake damaging enough to take down buildings and cause losses of life in the Boston area?

This is a good question and a difficult one, actually, to answer. The recent earthquakes in both Japan and also New Zealand taught us that we cannot totally rely on the fact that the last earthquakes happened a long time ago or we don't have them even in the human record to deduce that there would not be any earthquakes in the future in this area.

That actually doesn't sound very reassuring at all. So even though we may not have had a quake for about 400 years in the Boston area, you're saying we can't feel fully confident that there might not be one coming?

What we do know, in general, is that the level of activity in this area of the country is much lower than in other parts, like in California or Alaska.

If the probability is at least lower that it would happen here than elsewhere, does that mean that there's also a lower risk of a very damaging earthquake? Would it more likely be a minor earthquake?

Damage from an earthquake is not only a factor of the magnitude of the earthquake itself, but it's also a factor, first of all, of how close the earthquake is to the damaged area.

And I imagine it also depends on how prepared a city is for an earthquake?

That's the second thing. The second thing is how well the buildings are built. And in the case of of Boston, unfortunately, much of Boston is built on landfill, and that can liquefy during an earthquake.

What is the likelihood that a tsunami would hit this coast?

I think the likelihood that a tsunami will hit this coast is fairly low. The most likely source will be a landslide that happens underwater at an area of about 215 miles offshore Boston in an area known as the Continental Slope. This is the area that separates the very wide and shallow shelf. The shelf is about 100 to 150 meters deep from the deep ocean.

And what's the likelihood that we'd have a landslide on the Continental Slope?

We do not know that. That's precisely what we are studying now. We're trying to study what the probability is of such a landslide. To study this, we have to both map the landslides and then we have to date them to find out when they happen, and that's not such a simple process.

It sounds like you're saying we need to have the best science we can, we need to be prepared, and we need to have our emergency response ready if a natural disaster were to come.

This is correct. And I must say that, from my meager knowledge, those kinds of steps are being taken.