Music Welcome to Hub History

Jake:

[0:05] Welcome to Hub History where we go far beyond the Freedom Trail to share our favorite stories from the history of Boston. The hub of the universe. This is episode 300 Seismic Boston. Hi, I’m Jake. Where were you on the morning of Friday, April 5th when that earthquake shook Boston. Well, shook, might be overstating things a little bit jiggled. Boston. Maybe I was at work in the Fenway and there’s so much construction and demolition happening around my office that I had no idea that something had happened at least until the group chat lit up with everybody asking each other if they felt the earthquake. One friend said that her dogs wouldn’t calm down. Another one said that some chips came off the bricks of her South End foundation and co-host Emerita Nikki said that it interrupted a zoom call she was on because her camera shook. So noticeably the quake was good for a day’s conversation, but the effects didn’t go much further than that. It didn’t even lead to the memes that got created in the wake of the last earthquake that I remember feeling in Boston on August 23rd, 2011 with a picture of a bald eagle, an American flag superimposed over an overturned white plastic lawn chair and captions saying, 8 23 11, we will rebuild or never forget.

Jake:

[1:28] That time, I did feel my office chair move but just barely, imagine though a quake that came on with the sound of rolling thunder, one where the ground heaved like waves on an angry sea where people were thrown to the ground fissures opened up in the earth, and a tsunami was triggered that affected distant shores.

Jake:

[1:51] This was the experience of Boston during the great Cape an earthquake of 1755. And the effects of a similar seismic shock in modern Boston could be simply catastrophic.

Celebrating Episode 300

Jake:

[2:03] But before we talk about earthquakes in Boston, I just want to pause and say thank you to the loyal listeners who make it possible for me to make hub history, reaching episode 300. Seems like a cause for celebration. So I’ll take the opportunity to thank some of the show’s all time. Top supporters on Patreon.

Jake:

[2:22] Our top five longest standing supporters are Derek L. Michelle S Erica A Mariana M and Georgia B who have all been supporting the show for over five years now, Michelle S and Georgia B are also at the top of another top five list. My list of the sponsors who have given the most impure dollar terms after Michelle and Georgia, we have William L. Joshua L and Jh, I wanna say an extra thank you to these long term sponsors who’ve stuck with us through all the changes that the last five years have brought. As well as everyone who supports the show on Patreon or paypal. You pay this podcasts expenses and you enable me to create the show. If you aren’t yet supporting Hub History, it’s easy. Just go to patreon.com/hub History or visit hubor.com and click on the support us link, and thanks again to all our new and returning sponsors at this 3/100 episode.

Unusual Earthquakes in Boston

Jake:

[3:26] And now it’s time for the week’s main topic. Earthquakes are unusual here in Boston but not as unusual as you’d think. Our April 5th earthquake was centered in New Jersey and the one that got memed in 2011 was centered in Virginia while we think of earthquakes as being a west coast problem. Boston has felt earthquakes that started all up and down the east coast from Virginia to Quebec and occasionally much closer to home. Our recent quakes have become jokes and memes but an earthquake as powerful as some in the past would be no laughing matter. At the time of the Puritan great migration in New England, there hadn’t been an earthquake in Old England for 50 years since an offshore quake in the English Channel in 1580. There was a lot of literature about that. 1580 quake, especially by Puritan ministers who blamed Londoners sinful ways for the experience. So the idea of an earthquake wasn’t completely foreign to the Massachusetts Bay colonists by 1638. Still after living through the famine of their first winter here and experiencing a powerful hurricane in 1635 that they knew no precedent for the last thing they needed was one more natural disaster. But that’s what they got.

Jake:

[4:47] With a bit of poetic license. Cindy Purley describes it in his historic storms of New England the morning of Friday, June 1st 1638 was very pleasant. The sun shone brightly and the wind came gently from the west. The month of roses never opened more. Auspiciously, noon came and passed and the settlers proceeded to their various labors in the field. Between one and two o’clock, acute ears heard a low murmur of distant sound which grew louder and clearer until everyone heard what seemed to be the rumble of thunder far away in a minute or two. It increased in volume and in sharpness until it resembled the rattling of many carriages driven fiercely over granite pavements.

Jake:

[5:33] The people were startled by the noise and discontinued the work upon which they were engaged to discover whence the sound came and what it was a clear sky beamed down upon them. Not a cloud could be seen out of which the thunder tones could emanate. The more they thought of the matter, the greater grew their perplexity. Not many moments elapsed. However, until the earth began to tremble under their feet and terrified, they threw down their tools and ran reeling like drunken men with ghastly countenances to the first group of people they could find for men. Like many animals will flock together. When they are afraid the shaking of the earth increased to such a violent extent that people could not stand erect without supporting themselves by taking hold of posts or pilings or other fixtures.

Jake:

[6:22] Modern estimates put the epicenter of the 1638 quake near Concord New Hampshire with a magnitude of perhaps around 6.5. Governor John Winthrop’s journal entry for June 1st includes a description of the event and its extent. Now, I should note that in this week’s show, all the dates are gonna be given using the calendar of the time. So this is June 1st old style and anything taking place after the 1752 calendar switch will use the newer Gregorian Day, Winthrop’s journal for June 1st old style of 1638 says between three and four in the afternoon being clear, warm weather, the wind westerly there was a great earthquake. It came with a noise like a continued thunder or the rattling of coaches in London but was presently gone. It was at Connecticut at Narragansett, at Piscataqua and all the parts round about it shook the ships which rode in the harbor and all the islands, et cetera. The noise and the shakings continued about four minutes. The earth was unquiet 20 days after by times.

Jake:

[7:35] In his 1654 history of the New England settlement, Edward Johnson describes the panic that the quake caused among the English inhabitants again, using the older Julian calendar style for June 1st, this year, the first day of the fourth month, about two of the clock in the afternoon, the Lord caused a great and terrible earthquake which was general throughout all the English plantations. The motion of the earth was such that it caused diverse men that had never known an earthquake before being at work in the fields to cast down their working tools and run with ghastly terrified looks to the next company they could meet with all.

Jake:

[8:14] The English settlers had never known an earthquake before. And you’ll often see this event referred to as the first earthquake in New England. But of course, earthquakes have been occurring in this region for as long as the North American continent has existed. It’s just that there were no Englishmen here to witness them before a letter from the banished heretic Roger Williams to Governor Winthrop calls on oral histories kept by the Narragansett people to demonstrate that there had been a long history of earthquakes in New England. Before European settlement, the younger natives are ignorant of the like. But the elders inform me that this is the fifth within these fourscore years in the land. The first about three score and 10 years since the second, some three score and four years since the third, some 54 years since and the fourth some 46 years since, for those keeping score at home, that would be roughly 1568 1574 1584 and 1592.

Jake:

[9:17] The next time that the earth moved under Boston’s feet came about 25 years later, when a stronger shock centered further away was felt here as noted in a 1923 paper about earthquakes in the journal of the Boston Society of Civil Engineers. During the evening of January 26th, 1663 a very severe earthquake occurred in the province of Quebec where it did much damage and caused minor topographic changes, in Boston, dishes fell from the shelves and the tops of chimneys were broken.

Jake:

[9:50] This was a magnitude 7.0 quake that probably originated in Charlevoix along the Saint Lawrence River north of Quebec City. Strangely Sidney Perley noted that Boston was one of the only places where damage was recorded and the quake was felt most strongly along the shores of Massachusetts Bay. There were three strong aftershocks in about two weeks and a series of smaller ones that continued until July. These earthquakes were far away but caused damage here in Boston which might seem unexpected since we think of earthquakes as a California problem. We’re not located right over a fault where one tectonic plate is being forced under another and yet we feel earthquakes here. This is because earthquakes in the east are caused by a different mechanism than California quakes and because their force can be felt further from the epicenter than California quakes. An article about earthquake hazards from the northeast state’s emergency consortium explains the cause behind our new England quakes.

Jake:

[10:53] The North American Plate is being pushed away from the European plate and from the African Plate at the mid Atlantic Range, which runs down the center of the Atlantic Ocean from near the North Pole to near Antarctica, at its western edge along the US and Canadian west coasts, the North American Plate is pushing against the Pacific Ocean Plate and the Wanda Fuca Plate. Thus, the center of the North American Plate is being very slowly squeezed from both sides. This squeezing builds up pressure within the plate center and that pressure eventually gets released in the earthquakes that are recorded and experienced. Our northeast earthquakes are called intra plate earthquakes because they occur in the center of the plate away from the plate boundaries.

Jake:

[11:38] A 2018 article from the US Geological survey comparing eastern and western earthquakes reminds us that even on the long timelines of geology, Massachusetts is ancient with the granite outcroppings in the blue hills as the last vestiges of a 400 million year old volcano, Eastern North America has older rocks, some of which formed hundreds of millions of years before those in the West. These older formations have been exposed to extreme pressures and temperatures making them harder and often denser, faults in these older rocks have also had more time to heal which allows seismic waves to cross them more effectively when an earthquake occurs. In contrast, rocks in the West are younger and broken up by faults that are often younger and have had less time to heal. So when an earthquake occurs, more of the seismic wave energy is absorbed by the faults and the energy doesn’t spread as efficiently if the ancient rock under New England can transmit the force of a moderate quake over long distances. What happens when the epicenter is closer to home? Boston would find out on October 29th, 1727 when it was shaken by an earthquake with an estimated 5.6 magnitude in an epicenter near Newbury port as reported in the next day’s New England Weekly Journal.

Jake:

[12:59] Last night. And this morning we have in this place felt several shocks of an earthquake but that, which was the first, as is supposed was the most surprising and awful, which was about three quarters of an hour after 10 o’clock. The noise was like hard thunder which lasted for a space of about two minutes when the earth trembled and shook to a very great degree. The houses rocked as if they would have fallen down. And many of the inhabitants being amazed, ran out into the streets and then seemed to unite the cry. Lord, our flesh trembles for fear of thee and we are afraid of thy judgments.

Effects of the 1727 Earthquake

Jake:

[13:40] Sidney Purley reports that the summer of 1727 had been marked by a severe drought. And after that finally broke a strong September nor’easter caused widespread damage. On October 27th, an early snow fell across the region and there were still patches of snow on the ground. Two days later, when Cotton Mather wrote the night that followed the 29th of October 1727 was a night where to New England had never in the memory of man seen the like before the air. Never more calm, the sky. Never more fair. Everything in all imaginable tranquility. But about a quarter of an hour before 11, there was heard in Boston passing from one end of the town to the other. A horrid rumbling like the noise of many coaches together, driving on the paved stones with the utmost rapidity. But it was attended with the most awful trembling of the earth which did heave and shake so as to rock the houses and caused here and there, the falling of some smaller things both within doors and without, it cannot be imagined, but that it gave an uncommon concern under all the inhabitants and even a degree of consternation unto very many of them. This first shock, which was the most violent was followed with several others and some repetition of the noise at sundry times pretty distant from one another.

Jake:

[15:05] The number of them is not entirely agreed but at least four or five are allowed for the last of which was between five and six of the clock in the morning. The Boston weekly newsletter from November 3rd, 1727 reports that the quake in its aftershocks damaged some homes caused widespread fear but somehow spared Bostonians from death and injury. The earth reeled and trembled to a great degree. The houses rocked and crackled as if they were tumbling in the ruins. Many of the inhabitants were awakened out of their sleep with the utmost astonishment and others affrighted, run into the streets for safety through the goodness of God. The shock continued but about two or three minutes and though some damage was done in the houses, yet, none of the people received any bodily injury.

Jake:

[15:58] Around Boston dishes were shaken from their shelves and shattered on the floor and brick chimneys were shaken to pieces and needed to be rebuilt. In his historic storms of New England, Sidney Purley records that wooden houses were not damaged while brick houses suffered cracks and other damage that needed extensive repair. His account of the quake however, focuses more on the event’s effect on the natural landscape. The earthquake had considerable effect on the character of the land at Dorchester Mass. The noise seemed to come from the Blue mountains which some people who were out of doors when the shock came supposed to have suddenly sunk. The earthquake had considerable effect on the character of land, springs and wells. Some upland was changed into quagmire and in a few instances, Marshland was raised up being afterward too dry for its native grass to grow upon it.

Jake:

[16:55] In the meadow near the house then owned and occupied by Samuel Bartlett at Newbury Mass. A new spring of water was opened at Hampton, New Hampshire, a spring which had boiled over ever since it was first known. A period of 80 years having never frozen was so affected that the water failed to rise to the surface of the ground and afterward frozen moderate weather. The water of some wells was improved in quality. While in others, it was made permanently impure, some became dry and the temperature of several was greatly changed. Chasms a foot or more in width were opened at some places, fine white sand and ashes being forced up through them in varying quantities. In one place, we’re thrown up from 16 to 20 loads of sand with some slight indications of sulfur by throwing some of the sand on hot coals in a dark room. Blue sulfurous flames. The slight odor of brimstone were detected in another place. About 40 or 50 rods from the residence of Henry Sewell, the ground opened and for several days, water boiled out of the crevice like a spring. Within three weeks, it became dry and the earth closed.

Jake:

[18:08] If you listen to my episode about the aurora borealis of 1719 back in December, you might remember that this was a time when New England was torn between the old tradition of finding signs importance in natural events and the newer scientific worldview that saw Newtonian processes behind natural disasters.

Jake:

[18:28] In a 1973 paper titled the literature of the 1727 New England earthquake. William D Andrews describes how both mindsets were present in Boston’s response to the earthquake. New England ministers accepted the challenge of the earthquake presented, wheeled out the machinery of analysis and set to work, explaining the ways of God to his people. The Boston presses reacted almost seismically producing within a few months, 26 publications in which the effects of the quake can be measured in intellectual terms.

Jake:

[19:02] In these publications, both Natural Philosophy and Theology were employed in the task of explaining the earthquake in a manner consistent with current naturalistic and religious definitions of reality. Despite his own increasingly scientific mindset, you know that Cotton Mather was secretly satisfied when the shock of the earthquake drove Bostonians back to the welcoming arms of their churches. Writing when the greatly affected people had a little opportunity to look about them. In the morning. The pastors of the old North church directed the bells to be rung that such of the people as could and would might assemble immediately into some seasonable exercises of religion. The pastors of the nude joined them in sending up unto heaven. The supplications which the solemn occasion called for and the pastors in the other parts of the town made a speedy and hearty appearance and most affectionately united in a concurrence with them. The assembly that came together did more than crowd and fill the most capacious of our meeting houses.

Jake:

[20:04] While the lights of the aurora a few years before could be regarded as a harmless natural phenomenon. An earthquake was clearly the sign of an angry God whose wrath with the sinners of New England might bring on the ruin of his previously appointed people or even spark a judgment day with the paper by William Andrews continuing, the question then that all the ministers had to address themselves to was quite simple. Why had God shaken the earth? The first part of their answer was equally simple. God was angry with New England. The catalog of sins that was read off to explain the divine wrath included Sabbath breaking, neglect of family religion, swearing, oppression, adultery, heavy drinking, sodomy, disobedience of constituted authority and disrespect for the ministry. Such a list familiar to the readers of the Jeremiah. So popular in the declension of the late 17th century seemed to ministers in the second decade of the 18th century. Still a valid description of the sins of the New England people. New England was a land of sin and God always punished sin. But New England was especially culpable because it was a divinely appointed place inhabited by a chosen people.

Jake:

[21:24] In the secular press, natural philosophers argued about whether the cause was the explosion of underground vapors or the collapse of underground caverns or erosion by underground rivers. But Cotton Mather dismissed the mechanistic discussion is beside the point, let the natural causes of earthquakes be what the wise men of inquiry please. They and their causes are still under the government of him. That is the God of nature.

The Great Earthquake of 1755

Jake:

[21:53] The 1727 earthquake was the strongest to rock New England up to that point. But it paled in comparison to the one that struck some 28 years later, Harvard professor of science, John Winthrop, who was the great, great grandson of the Governor John Winthrop, who wrote about the 1638 earthquake describes the night of Tuesday, November 18th, 1755 as perfectly calm and serene with a fog in the marshes along the banks of the Charles River that dissipated early in the evening. The moon was nearly full and with an N A cloud in the sky, it lit the night brightly. In a letter he wrote to Thomas Birch that was later published in philosophical transactions. Professor Winthrop describes what happened at 4, 11 and 35 seconds a time he could fix with exactness because he had just set his clock to the true meridian time. And it was stopped by the violence of the night.

Jake:

[22:50] The earthquake began with a roaring noise in the northwest like thunder at a distance. And this grew fiercer as the earthquake drew nearer, which was almost a minute in coming to this place as near as I can collect from one of my neighbors who was then on the road in this town by his account, as well as that of others. The first motion of the earth was what may be called a pulse or rather an undulation and resembled to use his own comparison that of a long rolling swelling sea, and the swell was so great that he was obliged to run and catch hold of something to prevent being thrown down, the tops of two trees close by him, one of which is 25 the other 30 ft high he thinks waved at least 10 ft. And there were two of these great waving, succeeded by one which was smaller.

Jake:

[23:42] This sort of motion after having continued as it has been conjectured about a minute abated a little so that I who was just then waked. And I suppose most others imagined that the height of the shock was past but instantly without a moment’s intermission, the shock came on with redoubled noise and violence. Though the species of it was altered to a tremor or quick horizontal vibratory motion with sudden jerks and wrenches. The bed on which I lay was now tossed from side to side. The whole house was prodigiously agitated. The windows rattled the beams cracked as if all would presently be shaken to pieces.

Jake:

[24:27] According to Winthrop and other witnesses, the first shock lasted about 4.5 minutes an hour and 15 minutes later, a strong aftershock hit just before 5:30 a.m.

Witness Accounts of the 1755 Earthquake

Jake:

[24:40] One of the many people who was jolted awake by the tremor was a young schoolmaster in Worcester who happened to be visiting his father and his childhood home that night and wrote, we had a severe shock of an earthquake. It continued near four minutes. I was then at my father’s in Braintree and I woke out of my sleep in the midst of it. The house seemed to rock and reel and crack as if it would fall in ruins. About us. Seven chimneys were shattered by it within one mile of my father’s house. The earthquake had inspired the first entry in the diaries that John Adams would keep for the next 50 years.

Jake:

[25:22] Using the damage to his own chimney. As a guide, John Winthrop attempted to calculate the degree and direction of the motion caused by the earthquake. Concluding that his initial impression that the ground undulated like waves on an angry sea had been correct. I measured the greatest distance on the ground to which any of the bricks which are thrown off from the tops of my chimneys had reached and found it to be 30 ft and the height from which they fell was 32 ft.

Angular Motion of Buildings

Jake:

[25:50] Hence, it appears that our buildings were rocked with a kind of angular motion like that of a cradle. The Reverend Charles Chauncey published the sermon that he delivered at Boston’s old brick meeting house on the Sunday after the quake with an appendix to the printed version dated December 3rd in which he describes the physical effects of the earthquake.

Jake:

[26:12] Perhaps 1000 or 1500 chimneys have been damaged in various degrees, the roofs of some houses and the gable ends of a few others as far as the eaves were broken in either by the violence with which they shook or by the falling of the chimneys on them, it is said that many clocks and watches were stopped by the sudden and great agitation that was given them and some wells have not since yielded any water. The springs that fed them having been in one way or another stopped. The effects in many of our towns were as considerable as in this if not more. So in Pembroke, besides the breaking down of a number of chimneys, there were four or five chasms or openings made in the earth. From whence both water and sand were thrown out in situate near the large dwelling house of Mister Bailey. There was seven openings of the ground which still remain perceptible. One of them within 20 yards of the house and the whole seven within a few rods of it, from these have issued large quantities of water and at the lowest computation, 10 cart loads of a strange sort of earth as fine as flower and of a whitish complexion.

Jake:

[27:25] According to several accounts, the damage was most severe in parts of the town that were built on made land while many entire neighborhoods are built on fill today. The extent of landfill was fairly limited in 1755 mostly the waterfront near Long Wharf and the former town Cove.

Effects Beyond New England

Jake:

[27:44] In an August 1980 article for American heritage magazine, Jordan Houston wrote, fortunately, the effects were worst where the concentration of residences was leased near the docks and warehouses on the low loose ground made by the encroachments in the harbor where one witness described his passage impeded by large quantities of mortar and rubbish.

Jake:

[28:07] Although the large scale filling of the waters around the original peninsula of Boston did not begin until 1804, the city had already begun to creep into the harbor with the building of war such as the 54 ft wide long wharf which stretched 1586 ft into town cove, atop the fill and pilings were a road and merchant houses vulnerable to earthquake. The original residential settlement of the tri mountain as Boston was called in 1630 covered Beacon Hill, which is geologically stable bedrock and less responsive to earthquakes than silted sites. John Winthrop’s letter to Thomas Birch also contains a brief description of one of the most famous effects of the 1755 quake which also took place on the main land around the waterfront. The vein upon the public market house in Boston was thrown down the wooden spindle which supported it about five inches in diameter which had stood in the most violent gusts of wind being snapped off a new vein. Upon one of the churches in Boston was Benedet spindle two or three points of the compass.

Jake:

[29:19] If you’d like to learn more about the famous golden grasshopper weathervane that tops Fanuel Hall. Look up episode 196 from August 2020 where I describe the effects of the earthquake as well as 1/20 century theft and return of the famous weathervane with an estimated magnitude of 6.3. The 1755 earthquake’s effects were felt far beyond the bounds of New England. Professor Winthrop’s letter to Thomas Birch contained reports from other observers that the tremor was felt from Annapolis Royal in Nova Scotia to the eastern

Possible Tsunami in Caribbean

Jake:

[29:53] shore of the Chesapeake Bay in Maryland, casting an even wider net. His letter contains evidence that the earthquake may have caused a tsunami that hit the Caribbean. A few hours later, about two o’clock in the afternoon, the sea withdrew from the harbor of Saint Martin’s leaving the vessels dry and fish on the banks where there used to be three or four fathoms of water and continued out a considerable time so that the people retired to the high land, fearing the consequence of its return.

Effects on Wells and Springs

Jake:

[30:24] And when it came in, it arose 6 ft higher than usual. So as to overflow, the lowlands.

Jake:

[30:32] Much like they had. In 1727 the ministers and natural philosophers of Boston began debating the causes of earthquakes after the 1755 quake, many theories mirrored those that were put forward in the past underground explosions, caverns collapsing are reactions between volatile gasses. Thomas Prince, the Minister of Old South meeting house put forward a different explanation. Writing the more points of iron are erected around the earth to draw the electrical substance out of the air, the more the earth must needs be charged with it. And therefore, it seems worthy of consideration whether any part of the earth being fuller of this terrible substance may not be more exposed to more shocking earthquakes in Boston are more erect than anywhere else in New England. And Boston seems to be more dreadfully shaken.

Nature’s Ineffable Will

Jake:

[31:27] Oh, there is no getting out of the mighty hand of God. If we think to avoid it in the air, we cannot in the earth.

Jake:

[31:37] This condemnation of Ben Franklin’s lightning rods sounds like the work of a crank. But Prince was a respected thinker and his theory gained an unexpected following in Boston. In a note he wrote sometime later likely in 1758 future President John Adams took stock of this explanation and its adherence. Oh, there is no getting out of the mighty hand of God. This exclamation was very popular for the audience in general. Like the rest of the province consider thunder and lightning as well as earthquakes only as judgments, punishments, warnings, et cetera and have no conception of any uses they can serve in nature. I have heard some persons of the highest rank among us say that they really thought the erection of iron points was an impious attempt to rob the almighty of his thunder to wrest the bolt of vengeance out of his hand, and others that thunder was designed as an execution upon criminals that no mortal can stay. That the attempt was foolish as well as impious. This invention of iron points to prevent the danger of thunder has met with all that opposition from the superstition, affectation of piety and jealousy of new inventions that inoculation to prevent the danger of the smallpox and other useful discoveries have met with in all the ages of the world.

Jake:

[33:00] Professor Winthrop didn’t really need the young Adams to defend him as he was ready with a response of his own. I know no reason to think that Boston was more dreadfully shaken than other towns. Some of the effects of the earthquake may have been more considerable for their number there than elsewhere. But the reason of this is not that in Boston are more points of iron erected than anywhere else in New England. But that there are more brick houses erected there for the effect of a shock is more considerable on brickwork than upon woodwork.

Reverend Prince’s Theory

Jake:

[33:35] Perhaps trying to avoid the embarrassment. Reverend Prince faced after publishing his theory that lightning rods had caused the quake. Jonathan May uses sermon at the West Church instead attempted to position the cause of the disaster as outside the realm of natural philosophy. Such a terrible event he wrote could only be due to the ineffable will of God.

Jake:

[33:57] There is indeed such a thing as natural philosophy, which is of great use both through the purposes of life and godliness and which therefore well deserves to be cultivated. However, the whole of what goes by that name seems to be no more than the observing of facts, their succession in order and reducing them to a general analogy to certain established rules and a settled course and series of events called the Laws of Nature from their steadiness and constancy. This I say seems to comprehend the whole of what we usually call natural philosophy. But after all the improvements that have been made herein, how many things are there in the natural world which have never been and perhaps never will be reduced to any such general analogy or to the common known laws of nature. How many phenomena are there which we may call the irregulars, the anomalies and Heteroclite and the grammar and the great book and language of nature, by which God speaks to us as really as by his written oracles, where the laws of comets of inundations, of earthquakes, of Meteors, of tempests, of the aurora borealis of monstrous births, where the particular laws and causes of these and of 1000 other phenomena I say ever plainly discovered, I mean, so that they could be methodically calculated, foretold and accounted for as we can.

Jake:

[35:21] I mean, so that they could be methodically calculated for told and accounted for as we calculate foretell and account for common tides, eclipses, et cetera. No, surely this has never been done by the greatest philosophers with any tolerable degree of certainty and precision. Though there have been very ingenious and even probable hypotheses concerning some of these phenomena based on his own experience of the undulations of the ground. And his observation of bricks from his chimney landing 30 ft from his house. Professor Winthrop’s explanation of the earthquake’s origin included a phenomenon that would cause such lateral motion in a lecture he gave in the Harvard College Chapel a week after the earthquake. Winthrop stated the earth is not solid throughout but contains within it, many large holes, pits and caverns. As is agreed by all natural historians. There are very probably also long crooked unequal passages which run winding through a great extent of earth and form a communication between very distant regions. Some of these cavities are dry and contain nothing but air or the fumes of fermenting minerals.

Jake:

[36:34] If now these inflammable vapors be pinned up in closed caverns. So as to find no vent till they are collected in a large quantity. So as soon as they take fire in any part, the flame will spread itself wherever it meets with materials to convey it with as great rapidity, perhaps as it does in a train of gunpowder and the vapors produced from hence, will rush along through the subterranean grottoes as they are able to find or force for themselves a passage. And by heaving up the earth that lies over them will make that kind of progressive swell or undulation in which we have supposed earthquakes commonly to consist, and will at length burst the caverns with a great shaking of the earth as in springing a mine. And so discharge themselves into the open air.

John Adams’s Marginal Notes

Jake:

[37:20] The published copy of this lecture that’s in the collection of the Boston Public Library originally belonged to John Adams and it contains handwrit notes by Adams in the margins at several points. Besides his opinion on those that believe lightning rods caused the great earthquake. The marginal notes illustrate how excited and curious Adams was after another smaller quake was felt on March 12th, 1761. Since the progress of the seven years war, it allowed Britain to wrest possession of Canada away from France. He was eager for reports from Montreal Quebec as we go and points along the Saint Lawrence river that might determine the direction the quake shockwaves moved across the country, their strength in different areas. And ultimately, he hoped the cause of earthquakes themselves.

Jake:

[38:10] Despite all the ink that was spilled in debating the earthly causes of earthquakes. The 1755 quake faded from public consciousness faster than the last earthquake had familiarity breeds contempt and earthquakes were no longer seen as unprecedented in New England. In a footnote to his history of the province of Massachusetts Bay, Royal Governor Thomas Hutchinson wrote the terror was soon over there being very few repetitions of the shock. A great part of the people remembered the earthquake in 1727. And there had been other less violent ones in a few years which made them more familiar and lessen the apprehension of the danger and proportion.

Jake:

[38:52] There were lesser earthquakes in 1761 as noted by John Adams and again in 1783 which Abigail Adams cousin Cotton Tufts of Weymouth noted in his diary for November 29th as, between 10 and 11, a small shock of an earthquake, even as smaller tremors hit the state in 1846 1903 and 1940 the memory of the 1755 quake faded along with awareness of the dangers that a similar earthquake would pose in modern Boston.

Jake:

[39:25] The warnings for today are present in the reports from 1755 especially the notes that the shaking was worse on the made land around the harbor. And John Winthrop’s observation that the effect of a shock is more considerable upon brickwork than upon woodwork.

Comparing Boston to San Francisco

Jake:

[39:42] A paper about earthquakes. In a 1923 edition of the journal of the Boston Society of Civil Engineers compared the effect of the 1755 earthquake on Boston to the then recent 1906 San Francisco earthquake, with a magnitude of 7.9. The strength of that 1906 quake eclipsed even our 1755 disaster. But the effect on the extensive made land along the San Francisco waterfront provides a troubling example for Boston at present, a large part of the densely built up section of the Boston district is on made land. But during the 18th century, most of the city was on natural land. The San Francisco investigations showed that other things being equal, the damage to buildings increased in proportion to the depth and incoherent qualities of the foundation soil.

Jake:

[40:34] The destruction in San Francisco was confined largely to buildings located on Alluvium or filled ground. Consideration of these facts leads to the conclusion that modern Boston would suffer relatively more than 18th century. Boston did if an earthquake equal in intensity to that of 1755 should again visit the city structures of steel and reinforced concrete and other strongly constructed buildings would probably be but slightly damaged. But a great number of flimsy brick and wooden buildings especially on made land would certainly be destroyed and the loss of life might be very great.

Jake:

[41:13] With Winthrop’s observation that an earthquake shock is more damaging to brickwork than woodwork. The flimsy brick buildings that make up much of historic Boston are particularly vulnerable to a future quake that approached the intensity of the one felt here in 1755. An article about earthquake risk from the Northeast state’s emergency consortium notes, unreinforced masonry structures such as buildings built of red brick or cinder block with no other means of support are the most vulnerable when earthquake shaking takes place, the strongest shaking due to an earthquake is normally in the horizontal direction. Unreinforced masonry does not withstand horizontal shaking very well and it tends to crack and fall apart in such shaking. Old unreinforced masonry. Buildings are often especially vulnerable to earthquake shaking because old mortar tends to be very brittle and to break easily when shaken. Thanks to social media and memes the 2011 Virginia earthquake that we felt in Boston helped to raise the awareness of earthquake risk in Boston. At least somewhat in the wake of that 2011 event, Professor of civil and environmental engineering, Eric Hines wrote an article for Tufts now about how Massachusetts plans around the low probability but high consequence scenario of an earthquake similar to the one in 1755.

Rare Earthquake Occurrence

Jake:

[42:38] Extensive studies of the Boston area in the 19 seventies concluded that the chances are small that we’ll experience a destructive earthquake during our lifetimes call a 2500 year earthquake. The rarity of such an event implies that while we have a responsibility to protect human life, the return on investment for mitigating property damage would be low. For this reason. In the 19 seventies, Massachusetts became the only state in a moderate seismic region to adopt provisions to attempt to prevent building collapse for as little additional expenditure as possible. This philosophy differs from the prevailing conceptions of earthquake engineering on the west coast where large earthquakes are expected during our lifetimes and money invested in mitigating property damage is well spent. Massachusetts engineers have insisted on maintaining standards that are consistent with the last 40 years of practice in our state, which assumed that we should be designing buildings explicitly to withstand shaking from an event similar to or larger than the cape an earthquake.

Jake:

[43:44] The problem with a risk mitigation strategy that relies on designing buildings to withstand a K band level event is the number of buildings that have already been built and where they were built today. All of the back bay and most of South Boston and East Boston are built on made land as are large swaths of the south end, Alston and other neighborhoods. Jeremy Miller described the earthquake risk to this made land in sobering terms. In an article titled Boston’s earthquake problem that ran in the Boston Globe magazine on May 28th, 2006.

Jake:

[44:22] Amplification and liquefaction are two words often used by specialists to describe Boston’s earthquake vulnerability, amplification. When seismic waves hit a region of loose soil and become stronger was demonstrated to horrific effect in the Mexico City quake of 1985. A strong earthquake centered hundreds of miles away was strengthened at the surface by the soft soils beneath the city. Thousands of unreinforced buildings were leveled and 9500 people were killed.

Amplification and Liquefaction

Jake:

[44:54] Liquefaction happens when saturated sand or gravel deposits are shaken, increasing the water pressure between the grains and causing the soil to flow freely, when soil liquefies buildings may sink as though into quicksand and can buckle as their foundations shimmy and shift. That’s what happened in the Loma Prieta quake of 1989 which killed at least 63 people in the San Francisco Bay area. The Back Bay is now the most expensive zip code in the country and also at perhaps the highest risk of destruction in an earthquake of any neighborhood. One of these days, I’ll do an entire episode all about the filling of the back bay. But for now, a quick summary, you’ll have to do before 1821. The back bay was a tidal estuary but then it was dammed up in a failed attempt to harness the tides to power mills near what’s now mass ave. After that project went belly up, investors plowed money into filling the remaining lagoon so it could be used to build high end housing throughout the middle of the 19th century. The NC Munson company’s trains dumped thousands of loads of glacial sand and gravel. The crews leveled out into house lots creating the perfect conditions for liquefaction in a seismic event.

Jake:

[46:11] After the land was filled with sand. The graceful brownstones we know today were built upon it of unreinforced masonry, but their foundations render them even more susceptible to earthquakes than even other unreinforced masonry, throughout the back bay, South end Fenway and other areas that were filled in the 19th century. It was common to use spruce pilings to support new construction.

Jake:

[46:36] Not only houses but also public buildings like Trinity Church and the main branch of the Boston Public Library were built on spruce pilings. Basically, you strip all the branches off of a spruce tree, you turn it upside down and you drive it down into the ground until it sticks, do that enough times in a row, cut the tops of the pilings off at the groundwater line and you can run a granite footer across the spruce pilings and build a brownstone or a library on top. Some of the larger Back bay buildings required hundreds or even thousands of pilings to support the walls. With each corner of the massive central tower of Trinity Church sitting on 700 spruce pilings below ground level, picture entire forests in Maine being cut down and shipped down the coast of Boston to create the back bay and then multiply that out by the other neighborhoods that were developed in the 19th century. If that wasn’t enough, the groundwater levels in many areas are dropping, causing the pilings to dry out and exposing them to rot, which makes the buildings they support even more vulnerable to future earthquakes, and where they’re not drying out, groundwater levels are so close to the surface that they increase the risk of liquefaction exponentially.

Jake:

[47:53] Jeremy Miller’s 2006 article in the Boston Globe magazine tries to put a price tag on the potential damage in Boston. When the next big quake happens, we can guess the toll that an earthquake would exact on Boston. In 1990 researchers predicted that a magnitude 6.2 quake would cause 2 billion to $10 billion of damage in the Boston area along with hundreds of deaths and thousands of major and minor injuries. An unpublished 1997 study of Boston forecasts similar results. And in 1997 a Stanford University researcher concluded that given the high population density, large proportion of fragile buildings and precarious soil conditions, the risk of a quake causing catastrophic damage was greater in Boston than in San Francisco or Mexico City.

Uncertainty of Future Earthquakes

Jake:

[48:45] We don’t know exactly when or how those future earthquakes will come. Some estimates say that the 1755 earthquake was a once in 500 years event. Others say that it was more like once in 2500 years. And one theory that I read said that all the New England earthquakes in historical memory back to the 15 hundreds were just the aftershocks of a massive prehistoric earthquake that would dwarf anything witnessed in our time. It’s been 269 years since the 1755 Cape Band quake, but nobody knows when the next one will come, whether it was a 500 year event or a 2500 year event, those are just probabilities and the next big one could come next week or the next millennium, when it does come, historic architecture throughout Boston will be destroyed as the side to side motion of an earthquake shatters unreinforced masonry buildings and entire neighborhoods built on landfill could be swallowed up as solid ground is liquefied.

Jake:

[49:45] To learn more about the history of earthquakes in Boston. Check out this week’s show notes at hubor.com/three 00. I’ll have links to all the sources I quoted from this week including Professor John Winthrop’s lecture and letter and the sermons published by the Reverends, Jonathan Mayhew Charles Chauncey and Thomas Prince. There will be links to a pious poem by Jeremiah Newland, inspired by the 1755 quake and woodcut prints inspired by the earthquakes in 1744 and 1755. I’ll also link to the 2006 article about the earthquake risk in modern Boston so that you can join me in worrying about liquefaction.

Jake:

[50:28] If anybody out there has a tip about job openings in public history or tourism here in Boston, let me know I’ve been in health care it for almost 20 years now. But on the side, I’m turning into a pretty decent researcher and writer for all your content creation needs. And I’m also a former tour guide and tour company owner with a passion for sharing our city with locals and visitors alike. I could join your it team or I could use my digital humanity skills to create a podcast or other online content for your organization. If you have any thoughts or if you know somebody who might be hiring, get in touch, you can do that by emailing podcast at hubor.com. We are Hub History on Twitter, Facebook and Instagram and still marginally most active on Twitter.

Jake:

[51:17] You can find me on Mastodon as at Hub History at better dot Boston or just go to hubor.com and click on the contact us link while you’re on the site, hit the subscribe link and be sure that you never miss an episode. If you subscribe on Apple podcasts, please consider writing us a brief review. If you do drop me a line and I’ll send you a hub history sticker as a token of appreciation.

Jake:

[51:44] That’s all for now. Stay safe out there listener.