Woodcut engraving of Boston after the Cape Ann Earthquake, courtesy of the National Information Service of Earthquake Engineering

The ground moved today here in New England. Many of us in the Northeast have little to no experience with earthquakes – except for what we hear on the news or what we see in the movies- so it has certainly sparked the interest of the news media and has become the buzz around town.

Not knowing a great deal about earthquakes in this part of the world, I decided to dig a bit deeper.  I learned today that about 30-40 earthquakes strike New England each year, but only a few of those can be felt by people on the ground. Once every 50-90 years, the region is struck by a moderate quake (around a 5.0), much like the one that hit Virginia today (more here).  But in 1755, a much larger earthquake hit coastal New England, causing a great deal of damage.

The historic quake, one of the largest ever recorded in New England, struck the region at about 4:30 in the morning on November 18. Lasting for more than a minute, damage was reported from Portland, Maine to the South Shore of Boston, while it was felt as far north as Halifax, Nova Scotia and South Carolina to the south. Boston, in particular, suffered a great deal of damage, where as many as 1500 chimneys fell down and the gable ends of about 15 brick buildings shattered. Some church steeples tilted and a great deal of debris fell to the streets, making many impassable. With the population greatly frightened by the event, local ministers conducted prayer services and government officials proclaimed fast days, fearing that they had just experienced the wrath of God. (Read more about the history of the Cape Ann Earthquake here.)

The epicenter of the Cape Ann earthquake was actually about 25 miles east of Rockport in the Atlantic Ocean, a spot that has seen a great deal of seismic activity over time.  Interestingly (and scarily) enough, if the 1755 Cape Ann Earthquake were to happen today, the quake would result in billions of dollars in damage and the potential loss of hundreds of lives. The construction of docks, wharves, and other significant land-making projects has made the city fragile in many ways, due to the pressures put onto the local water table.

Hold on tight!