Historical Seismicity of New England

1. Historical Seismicity of New England Justin Starr Weston Observatory Department of Earth and Environmental Sciences, Boston College

2. How does one determine an earthquake epicenter and magnitude, if no seismic data is recorded?

3. What would you do if you felt an earthquake today? …….after the shaking stops, of course. • Correspondence and diary/journal entries

5. The Pilgrims felt their first earthquake in 1638. From William Bradford’s history of Plymouth: “This year (1638) aboute ye 1. or 2. of June was a great & fearfull earthquake. . .the earth begane to shake and came at length with that violence as caused platters, dishes, & such like things as stoode upon shelves, to clatter and fall downe; yea persons were afraid of ye houses them selves. . .ye earth shooke with yt violence as (the people) could not stand without catching hould of ye posts & pails yt stood next them.” So powerfull is ye mighty hand of ye Lord, as to make both the earth & sea tremble before him” Magnitude 6.5 earthquake centered in central New Hampshire (in Ebel, Seism. Res. Lett., 1996).

7. The Charlevoix Earthquake of 1663 M7.0 - M7.5 (?) • The largest known earthquake in the northeastern U.S. and nearby parts of Canada • Shaking reported to have lasted about 3 minutes and caused large landslides and sandblows • 375 mi away in Boston, chimneys fell, pewter fell from shelves and many people ran into the streets • Aftershocks were felt in Quebec for more than 7 months.

9. 1727Newbury Earthquake The earthquake damaged chimneys and stone walls in Newbury, Massachusetts and nearby towns. It was felt to Philadelphia and Casco Bay, Maine. Estimated magnitude: 5.6. Over 150 aftershocks documented. The Roman numerals on this plot are modified Mercalli intensities. MMI VI is minor damage, MMI VII is moderate damage, MMI VIII and higher is major damage.

11. The Great Cape Ann Earthquake of 1755 About 1/3 (1,200 to 1,500) of the chimneys in Boston were damaged, as were the brick walls of several buildings.Damage was reported from Portland, Maine to south of Boston. The shock was felt from Halifax, Nova Scotia to Winyah, South Carolina. Estimated magnitude: 6.0 – 6.3

12. On November 20, 1755, the Boston Weekly News-Letter reported: "Last Tuesday Morning about half an Hour past Four o'Clock, the Weather being serene, the Air clear, the Moon shining very bright, we were surpriz'd with a most terrible Shock of an Earthquake: The conditions were so extreme as to wreck the Houses in this Town to such a degree that the Tops of many Chimnies, and some of them quite down to the Roofs, were thrown down. . . ." The Boston Gazette, or Country Journal newspaper of Nov 24, 1755 reported: “By a Person which came in Capt. Burnam, who arrived at Marblehead from Cadiz last Week, we learn that they felt the above Shock 70 leagues E of Cape Ann, at ½ Past 4, but concluded that they ran foul of a Wreck, or got upon a Bar, but on throwing Over the Lead, found they could not sound in 50 Fathom of Water, and continued Ignorant of what it was till morning, when to their great Surprise, they saw a vast Number of Fish, large as well as small, floating on the Water dead, when they concluded It could be nothing but an Earthquake…”

14. An illustration of the 1755 earthquake in Boston.

15. Most recent damaging earthquake in the northeastern U.S. was on June 23rd, 2010. There was minor damage within about several kilometers of the epicenter. It was felt in Boston, New York, Buffalo and even Michigan. Magnitude: 5.0 .

16. Images from Jean Levac, The Ottawa Citizen, June 24, 2010

17. Major Earthquakes in the Northeastern U.S. and Southeastern Canada 1638-2010 1663 Known or suspected earthquakes of magnitude 5.0 or greater in New England Notable damaging earthquakes centered in New England in 1638, 1727, 1755, 1904 and 1940. 1904 1940 1638 1755 1727

18. Thank you