Earthquake threat real in region

Could it happen here?The world has been riveted by the unfolding tragedy in Haiti since the 7.0 earthquake on Jan. 12 and many in New England may not have given much thought or concern to the notion that the ground could ever unleash similar fury here.A leading Massachusetts expert on the matter warns, however, that there is a very real possibility our region will one day be hit by a tremor of equal or greater magnitude.”In my opinion, we cannot rule out the possibility of an earthquake the size of the one that hit Haiti last week,” said Dr. John Ebel Ph.D, director of the Weston Observatory of Boston College and professor of Geophysics at B.C. “We do have steady earthquake activity that happens in New England year in and year out.”Rough rule of thumb is that we get anywhere from three-to-six felt earthquakes per year somewhere in the New England region. You look anywhere in the globe where there are regular earthquakes occurring and those places usually, sooner or later, have larger and potentially damaging quakes.”The most severe earthquake recorded in our area, measuring between 6 and 6.25 on the Richter Scale, hit 21 years before our nation formed. The Cape Ann Earthquake was centered off the coast of Gloucester and occurred the evening of Nov. 18, 1755. That quake toppled nearly 1,500 chimneys in Boston and was felt from Nova Scotia down to South Carolina, Ebel said.Although newer buildings in the U.S. are much stronger than those that crumbled in Haiti – and structures including hospitals are required today to be built to withstand strong earthquakes – Ebel estimates that an earthquake the size of the one that devastated Port Au Prince last week would still cause billions worth of damage here.”We have many older structures that are not built to withstand earthquakes very well. Brick, cinderblock buildings and un-reinforced concrete buildings cannot withstand earthquake shaking very well,” Ebel said.Most damaging earthquakes, Ebel said, are typically those where the plates of earth shake sideways, like the one in Haiti.”An old building like a 19th century mill building made of brick would probably take damage in an earthquake like that,” Ebel said.The quake that hit Indonesia and spurred the tsunami in December 2004 was a different type, where an undersea plate shifted up, thus spurring the massive tidal wave. That was certainly as devastating in terms of human toll (250,00 dead) and property loss, but it was tsunami and not the shaking that was the culprit there.Ebel said cities built on landfills and other places where there are soft soils can amplify the shake of an earthquake. An area of particular concern, he said, is Boston’s Back Bay, which was constructed on a large landfill. The damage there from a 6.25 earthquake would be much more severe, he said, than someplace like the hills of Brookline.”Lynn would be on the same scenario as you would for Boston, urban versus a suburban or rural event, because you are talking about more people, but also the type of structures you have in inner cities – tall buildings, brick buildings, the types of things which can lead to many more casualties,” said Peter Judge, information officer at the Massachusetts Emergency Management Agency (MEMA).Although scientists are near an early warning system for earthquakes, that does not exist now. Damage from quakes begin at around magnitude 5 on the Richter Scale (each point on the scale is 10 times more powerful). Ebel said quakes of that magnitude hit New England every 50 or 60 years on average. The last earthquake of that magnitude occurred near Ossipee, N.H., in 1940.Considering the average alone, New England is due for an earthquake magnitude 5 or higher, but he pointed out that averages are not accurate predictors.”If you have two earthquakes that occur 99 years apart and then another earthquake one year later, the average repeat time for those earthquakes is 50 years, but that doesn’t mean you have an earthquake every 50 years,” Ebel