East Coast Earthquakes and Tsunamis

by The Political Commentator and GEI Staff

Econintersect: An East Coast earthquake is definitely more common than most may think. (See first graphic below). So what about the potential for a tsunami to hit New York or New Jersey? To put in proper perspective the 5.8 magnitude Virginia earthquake, the four graphics to follow give an idea of how prevalent earthquakes on and off the East Coast actually are. They are not as prevalent as on the West Coast prevalent but enough to think about.Prior to my office shaking yesterday I never really gave the potential for a trembler any serious thought, but these two graphics tell me that perhaps I should. The first graphic indicates all earthquakes that have been recorded.

The second graphic shows the mid-Atlantic continental shelf located about 100 off of the coast of New York and New Jersey. It starts at 500′ deep, goes to 7,000′ deep and then drops to as deep as 20,000′!

Imagine for a second a severe earthquake hitting off of the coast of New York or New Jersey that caused a significant part of the cliff to break off and fall several hundred or several thousand feet..

What size could a tsunami potentially be from an event like that and what kind of damage would that do to New York City?

The history of U.S., Latin America and northern South America tsunamis is shown in the third graphic below.

A notable event occurred on November 18, 1929 when an earthquake on the Grand Banks off Newfoundland triggered a landslide 100 miles off the coast. The resulting 15 foot tsunami killed at least 28 people in sparsely populated Newfoundland. The following graphic shows the map of the time and magnitude of the tsunami wave emanating from the earthquake area.  The earthquake was recorded as a magnitude 7.2.

Editor’s note: A newspaper account from November 22, 1929 can be read here. The initial reports of 36 dead was later reduced to “at least 28” based on the actual count of bodies recovered.

Sources:  The Political Commentator and Geology.com