Earthquake!

28 February 1925

When most Canadians or Americans think of earthquake-prone areas, what first comes to mind is the west coast of North America, especially California, the site of many memorable earthquakes, including the great San Francisco earthquake of 1906 which destroyed over 80 per cent of the city and killed roughly 3,000 people. Baseball fans of a certain age will also recall the Loma Prieta quake that hit the San Francisco area in 1989 and disrupted Game 3 of the World Series between the San Francisco Giants and the Oakland Athletics. 67 people lost their lives and close to 4,000 people were injured in that disaster. Property damage was estimated at $5 billion.

Both of these San Francisco earthquakes occurred on the 1,200 kilometre-long San Andreas Fault, the tectonic boundary between the Pacific Plate, which is sliding northward, and the North American Plate which is moving southward. The fault is part of the “Ring of Fire,” an area prone to earthquakes and volcanoes that follows the perimeter of the Pacific Ocean.  The Loma Prieta quake had a magnitude of 6.9 on the moment magnitude scale (Mw). The moment magnitude, which is typically used today, is calculated slightly differently from the older but better known Richter scale developed by Charles Richter in 1935. But both scales measure the magnitude of the earth’s movement as detected by a seismograph on a logarithmic scale. The moment magnitude scale is more accurate, especially for large earthquakes. The 1906 quake is estimated to have had a magnitude of 7.9 Mw. Although it was only one step larger on the logarithmic scale than the 1989 temblor, it released roughly 32 times more energy (101.5). A two-step increase in magnitude would release 1,000 times more energy (103).

Vancouver and Victoria are Canada’s most earthquake-prone cities. They are located in the Cascadia subduction zone, a 1,000 kilometre-long fault that stretches along the west coast from the top of Vancouver Island down to northern California. Three tectonic plates, the Explorer, the Juan de Fuca and the Gorda, are moving east under the North American plate. This area has been hit by several major earthquakes in the past, including a massive one in 1700 centred off of  Vancouver Island that had an estimated magnitude of 8.7 to 9.0 Mw. In other words, it released roughly 32 times more energy than the 1906 San Francisco earthquake and more than 1,000 times more energy than the 1989 Loma Prieta earthquake. In 1949, an 8.1 Mw tremblor hit the Haida Gwaii (formerly the Queen Charlotte Islands) region, north of Vancouver Island.

After the western metropolises of British Columbia, the next most seismically active cities are Montreal and, believe it or not, Ottawa. Both cities are located in the Western Quebec Seismic Zone which has two sub-zones, one along the Ottawa River and the other from Maniwaki, north of Ottawa, to Montreal. Incredibly, there is on average one earthquake every five days in this region. To the east of the Western Quebec Seismic Zone is the even more active Charlevoix Seismic Zone, located close to Quebec City along the St Lawrence. Here, one earthquake is recorded on average every one and one half days. Of course, the vast majority of the earthquakes in both zones are only small earth trembles that are scarcely noticed except by seismographs—but not always. A powerful earthquake with an estimated magnitude of 7 Mw struck the Charlevoix-Kamouraska area in 1663, followed by nine days of aftershocks.

Earthquakes, Natural Resources Canada

The Western Quebec Seismic Zone. The dots represent earthquakes of magnitude 3 or higher since the beginning of the twentieth century. Source: Natural Resources Canada.

Seismic activity in this part of Canada is not well understood. Much of central-eastern Canada is covered by the Canadian Shield, a massive, ancient, and stable rock formation that makes up the interior of the North American Plate. Lacking plate boundaries, this is not a locale that one typically associates with earthquakes. According to Natural Resources Canada, eastern Canadian earthquakes are due to “regional stress fields” and are concentrated in areas of “crustal weakness.” The end of the last ice age, which had caused land once pressed down by the weight of glaciers to rebound, may be a factor. Some scientists believe that “post-glacial rebound stress” has directly caused earthquakes, or has reactivated old faults which have led to earthquakes.

Ottawa residents are likely to remember the moderate magnitude 5.0 Mw earthquake that struck the nation’s capital in late June 2010. The epicentre was located roughly 60 kilometres north of Ottawa near Buckingham, Quebec. It was felt in Toronto, Montreal and south to New Jersey in the United States. Damage was slight. Some windows were broken, and power was cut in parts of downtown. No injuries were reported.

This earthquake was reportedly the strongest Ottawa had experienced in sixty-five years. That earlier earthquake struck on 28 February 1925 at 9.20.17 pm Eastern Standard Time. The capital was shaken by a 6.2 Mw earthquake whose epicentre was located near Shawinigan, Quebec, 260 kilometres distant, in the Charlevoix Seismic Zone. So strong was the quake that it was felt more than 1,000 kilometres away. On the Modified Mercalli Index, which measures an earthquake’s intensity or effects as opposed to the amount of energy released, the earthquake reached level VIII (severe) (out of ten grades) in the area close to the epicentre. At this level, people panic, trees are shaken strongly, and there is widespread building damage, including fallen chimneys, walls and pillars.

While the epicentre of the 1925 earthquake was more than 200 kilometers further away than the 2010 earthquake, its effects on Ottawa were considerably larger owing to its increased magnitude. A 6.2 Mw earthquake is almost 16 times bigger than a 5 Mw earthquake and is 63 times stronger in terms of energy released.   After the earthquake, The Ottawa Evening Journal reported that the capital had not seen such excitement since Armistice Day that ended the Great War in 1918. Fortunately, there were no injuries and property damage was slight.

The 1925 earthquake lasted ten minutes or longer in some locales, though tremors apparently continued for several hours, keeping anxious citizens awake through the night wondering whether a still larger quake was still to come. Residents of Sandy Hill and Ottawa South were the worst affected in Ottawa, mostly likely because of the soft clay on which these neighbourhoods sit. Some people became nauseated by the rolling motion underfoot which was described like “the swaying of a rapidly moving train or the rolling of a small boat.” This was followed by an intense up and down bumping, accompanied in some areas by a low, thunder-like noise, or rumble. The earth’s movement was most strongly felt by those in the upper floors of apartment buildings, especially those situated close to the Victoria Memorial Museum (now called the Museum of Nature). At the Queen Mary Apartments on the corner of Elgin and McLeod Streets, walls and ceilings cracked, furniture bumped, plaster fell from walls, china rolled off of plate rails, and doors creaked. In the nearby Mackenzie Apartments, several windows broke while on the upper floors plaster dust covered furniture and mirrors broke. Many residents rushed from the building in panic. At the Victoria Memorial Museum, plaster fell from the walls. Oddly, cracks in the entranceway closed, making it the only building to have possibly benefited from the earthquake. The building, which was constructed on clay, had been plagued with cracks since it was completed in 1911. Indeed, the tower above the main entrance had to be removed a few years after the museum was completed for reasons of public safety owing to settling.

At the Auditorium on Argyle Street, the Ottawa Senators had just started the second period of a game with their arch rivals the Montreal Canadiens when the earthquake struck. With the teams locked 0-0, many of the rabid 8,000 fans in the Ottawa Auditorium didn’t at first notice anything was amiss. A loud noise that rattle the arena was attributed to an automobile that had just completed an advertising tour of the rink during the first intermission. According to The Globe newspaper, the arena vibrated violently. A crash, possibly due to a falling window, almost sparked a panic. However, once the vibrations eased, people settled down again to continue watching the game. On the ice, the Ottawa goalie, Alex Connell, thought he was becoming ill. A “shimmy” under his feet made him feel dizzy. He called out to his defencemen that he felt funny. (For those who are wondering, the Senators went on to beat the Canadiens 1-0.)

At the Lisgar Collegiate, a musical event was underway in the school’s auditorium. Miss Roxie Carrier was on stage singing a solo as the Belle of Antiquera in a production of the Spanish operetta “El Bandido.” When the earthquake struck and built in intensity causing the floor and walls to sway, members of the audience began to panic. Shrieks from the balcony brought people to the feet. Many started to head to the exits. However, the presence of mind of Miss Carrier, who calmly remained on stage, as well as the prompt response of the ushers and policemen settled the audience who returned to their seats.

In the hours following the initial shocks, in what may have been an international first, Ottawa’s radio station, CNRO of the Canadian National Railways, broadcasted full and authoritative news updates about the earthquake, relaying the latest information from the Dominion Observatory, which was monitoring the tremors with its seismograph, and from railway agents through the Canadian National Telegraphs. These news reports did much to allay the fears of area residents who were concerned for the safety of absent loved ones. Mr J. G. McMurtrie, superintendent of broadcasting at CNRO, said that the shock was plainly felt at their studio. Conditions were quite alarming for a time at their operating room on the roof of the Jackson building, one hundred and twelve feet above Bank Street.

Although Ottawa was badly shaken, damage was slight. Other cities experienced more serious effects. In Quebec City, there was a general panic. A section of Union Station’s roof was damaged and many windows were broken. Several poorly-built shacks on the city’s outskirts were reportedly flattened. In Montreal, a fire started in the furnace room of St James’s Basilica owing to a broken fuel line causing $10,000-15,000 damage. A stone church in St Hilarion, Quebec also collapsed. Although details are sketchy, newspapers attributed the deaths of two women to the earthquake, one in Trois-Rivières and another in Toronto, due to fright.

Roughly ten years later in November 1935, the same area, including Ottawa, was shaken by another serious earthquake, this time a slightly smaller magnitude 6.1 Mw tremblor centred in Timiskaming in the Western Quebec Seismic Zone 360 kilometres from Ottawa. Again, although the capital region received a good shaking, there was little damage.  The most significant effect was a landslide in Parent, Quebec which took out a section of the Canadian National Railway line.

With increased awareness of Ottawa’s vulnerability to seismic disturbances, work has been undertaken to assess and strengthen existing buildings, such as the Bank of Canada’s head office on Wellington Street, and the Museum of Nature on McLeod Street. Fortunately, the Parliament Buildings are constructed on solid rock and are less susceptible to damage from earthquakes. A major quake could however cause serious damage to historic masonry buildings in the Byward Market area. Timber-framed homes, even those that are externally brick-clad, are likely to fare relatively well as timber frames can flex in response to tremors. Natural Resources Canada’s website provides a useful list of things that can be done to protect our homes from damage in the event of a significant earthquake.

Some words of caution: when earthquakes occur, our natural reaction is to run outside. However, studies have shown that it’s better to drop down, and cover your head preferably close to an interior wall or, better still, under a sturdy table, and wait until the shaking stops. Being outside exposes people to the risk of falling glass, masonry and other debris, a particular concern in high-rise urban areas. If you are outdoors, get away from buildings. If you are in a car, pull over and stay away, if you can, from anything that might collapse such as buildings, overpasses or bridges. Good luck to all should “the big one” strike!

Sources:

CBC. 2011. 2010 quake led Ottawa to change policies, 23 June.

Earthquake Alliance, 2018. How to protect yourself in an earthquake, https://www.earthquakecountry.org/dropcoverholdon/.

Globe (The), 1925, “Eastern Canada and U.S. Shaken By Earthquakes,” 2 March.

Montreal Gazette (The), 1925. “Great Mass Of Rock In Earth’s Crust Slipped,” 2 March.

—————————-, 1925. “Seismic Narrative Told By Broadcast To Radio Fans,” 2 March.

—————————-, 1925. “Fought Blaze In Furnace Room Of St. James Basilica,” 2 March.

Natural Resources Canada, 2016. Earthquakes Canada,” http://www.earthquakescanada.ca/index-en.php.

Ottawa Citizen (The), 2017. “A major earthquake could hit Ottawa. Are we prepared?” 21 April.

————————-, 2017. “Magnitude 3.3 earthquake shakes Ottawa-Gatineau,” 14 August.

Ottawa Evening Journal (The), 1925. “Villages Are Terrified As ‘Quake Wrecks Church.” 2 March.

—————————, 1925. “Quake Closes Cracks In Victoria Museum,” 2 March.

—————————, 1925. “Many Tenants Of Apartments Were Alarmed,” 2 March.

—————————, 1925. “Ottawa Severely Rocked By Heaviest Earthquake Recorded For Centuries,” 2 March.

—————————, 1925. “Miss Carrier IS Heroine At School Event,” 2 March.

—————————, 1925. “First Shock Worst Down Quebec City,” 2 March.

—————————, 1925. “People Of Ottawa Relate Earthquake Adventures,” 2 March.

—————————, 1935, “Locate Centre of ‘Quake 200 miles From Ottawa,” 1 November.

—————————, 1935. “Ottawa Shaken Today By Three Earth Tremors,” 2 November.

Wu, Patrick and Johnston, Paul, 2000. “Can deglaciation trigger earthquakes in N. America?” Geophysical Research Letters, Vol. 29 pps.1323-1326, 1 May.

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2 thoughts on “Earthquake!

  1. Good Morning James:

    I got behind reading your postings. I just now read your last three articles and enjoyed each one: I didn’t know before reading “The Last Man Hanged in Ottawa”, that there have been only three executions at the Nicholas Street jail. Your article on Eugene Lamont’s life was both interesting and informative and confirms again that failure to pay attention to the disadvantaged among us is often a major contributing factor to later very serious problems. I knew about the existence of “Dow’s Lake and its Causeway” but what you wrote added many details to my understanding of the building of the causeway and the eventual size and shape of Dow’s Lake. Today’s posting “Earthquake!” taught me much about the 1925 earthquake. In fact, I knew nothing at all about that one but I do remember the 2010 earthquake although, had someone asked me, I would have said it happened only recently, not eight years ago! Guess that’s old age memory at work.

    Thank you very much for all three. They were very good reads.

    John

    >

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