A Boston Earthquake?

Given what's happened in Haiti, I remembered reading about the potential dangers of a Boston Earthquake not long back. I decided to do a little google search - and, indeed, Boston and the New England region aren't so safe from quakes as we'd all like to believe.

Local scientists have been bringing up the inevitability of a reasonably bad Boston Earthquake for more than a decade now, but given what's happened in Haiti, maybe more people in Boston will be willing to look into it? Why Boston in particular -- and not all of New England? Well, Boston is particularly at risk. From the link:

Our earthquake threat is made more pressing by what distinguishes Boston among American cities: its elegant brick-and-mortar architecture, which in many cases sits on loose, unstable soil. Experts also warn that the city's aging infrastructure and utilities -- sewer mains, gas lines, bridges, and overpasses -- are rife with vulnerabilities.

When people think of Boston, it's important to think of a city that is much larger than it's 18th Century map -- the city has been greatly expanded through the use of landfills. This is particularly relevant because during earthquakes, landfills liquefy. Yes, liquefy. Anyone care to take a guess at what the Back Bay would look like after the buildings in it fall apart as the ground below liquefies? It could be a disaster.

All that said, it's not all bad. Thankfully, not all the buildings, even in the areas built on landfills, are especially dangerous. Anything built after 1973 should be solid, because that's when Massachusetts adopted the same seismic building codes that existed in California. The skyscrapers, by and large, should be okay. The Big Dig's got the latest technology in dealing with that threat, so that should be relatively safe. Even the oldest homes in suburbs surrounding the city should escape the worst, because most of them are built on solid ground.

These kinds of dangers are hard to plan for and even harder to justify major expenses in fixing -- because one never knows when the next, big Earthquake will strike. However, Boston's had them in the past -- Earthquakes as high as 6th magnitude or higher -- and not particularly long ago (1755 was the last bad one -- and there was one in 1638 that was even worse, in the 7s). Scientists think Boston's only likely to get a bad earthquake every couple of centuries, but it's not an exact science -- and it's been a few centuries already.

At the very least, this is something worth thinking about -- even if it's something as simple as offering carrots to property owners to test foundations, many of which in Boston are in such bad shape already that it may not even take an Earthquake to cause homes serious structural damage, as foundations settle. It's actually happened to homes in Boston already. Given that knowledge is power, it's always a distressing fact that the City of Boston knows so little about what's below the ground. At the very least, we need to know that -- not only to plan for any future seismic activity, but for all the other myriad problems old pipes and rotten foundations can cause.