1929 Grand Banks earthquake

The Earthquake and Its Causes

The 1929 Grand Banks earthquake originated from a rupture along two faults approximately 250 kilometres south of Newfoundland's Burin Peninsula, at the edge of the Grand Banks. The epicentre was located on the steep Laurentian Slope, where the continental shelf drops sharply from about 100 metres to 2000 metres depth into the deep Atlantic. The shock, which lasted about one minute and was felt by residents of Saint Pierre and Miquelon around 4:30 p.m., registered across a vast area, with reports from as far away as New York City, Montreal, and throughout the Maritime provinces, and was rated at intensity IV (Slight) to VI (Strong) on the Rossi-Forel scale in Prince Edward Island. The earthquake's maximum intensity was rated VI (Strong tremor) on the Rossi-Forel scale, indicating significant shaking but not enough to cause major structural damage on land in Newfoundland, though dishes rattled and lamps swayed. The seismic energy released was the product of tectonic stresses building up within the submarine rock roughly 20 kilometres below the seafloor, along a fault rupture estimated to be 100 kilometres long in the Laurentian Slope seismic zone. This event remains the largest historical earthquake recorded in eastern Canada, demonstrating the significant seismic potential of the offshore region and leading Natural Resources Canada and the United States Geological Survey to create a revised intensity map in 2002.

The Submarine Landslide and Tsunami Generation

The earthquake's most consequential effect was the triggering of an enormous submarine landslide, estimated to have displaced 200 cubic kilometres of sediment. This volume made it Canada's largest recorded submarine landslide, up to 500 times larger than the 1894 Saint-Alban subaerial slide in Quebec. The slump of glacially deposited sediments, which had accumulated over tens of thousands of years, off the continental slope generated a powerful turbidity current, a dense, fast-moving underwater flow of mud and sand that carried material into the deep ocean. This current travelled down the slope at high speed, sequentially snapping 12 transatlantic telegraph cables that lay on the ocean floor over a considerable distance, an event that would later provide critical data for scientists. The sudden displacement of such a massive volume of material also displaced a colossal amount of seawater, which generated the tsunami that radiated outwards from the landslide site. The transformation of the landslide into a tsunami wave was not understood at the time, and the broken cables later provided crucial evidence for scientists piecing together the event's sequence and the behaviour of turbidity currents, giving birth to a new field of study.

Impact on Newfoundland's Burin Peninsula

It arrived as a series of three main waves over a period of about thirty minutes, with the first wave often being a trough that caused the sea to recede dramatically before the destructive bore rushed in, as described in contemporary newspaper accounts. Witnesses like Mr. Bartlett aboard the S.S. Daisy reported the water receding first and then coming in with a bore that collapsed, causing his shop measuring 30 by 60 feet to be lifted bodily and deposited 200 feet away while the steamer struck bottom. Wave heights varied significantly with local geography, reaching 3 to 8 metres along open coastlines but towering to a runup height of 13 metres in the narrow, funnel-shaped bays and inlets that characterize the peninsula, with some reports from Burin indicating waves up to 15 feet that swept away practically everything along the waterfront from Port au Bras to Great Burin. The destruction was catastrophic for the isolated fishing communities, where hundreds of people were left destitute. Entire waterfront premises were swept away, homes were lifted off their foundations and carried inland or out to sea, and fishing boats, stages, and gear were destroyed, crippling the local economy. Over 40 villages were affected, more than 1,000 people were left homeless, and total property losses were estimated at over $1 million in 1929 currency, devastating an economy rooted in the seasonal cod fishery that had exported 53,000 metric tons of salt cod just four years earlier in 1925.

The earthquake and tsunami had the largest impact on Newfoundland, Canada and the French Overseas territory of Saint Pierre and Miquelon. On the Burin Peninsula in Newfoundland, the tsunami destroyed many south coastal communities. The tsunami also caused significant damage on the island of Saint-Pierre in Saint Pierre and Miquelon, submerging docks and flooding the lower part of L'Île-aux-Marins. More than 40 local villages in southern Newfoundland were affected, with numerous homes, ships, and fishing gear destroyed.

• Burin: Waterfront premises swept away from Port au Bras to Great Burin, with an immense 15-foot wave reported and scarcely a waterside premises left standing.
• Kelly's Cove and Stepaside: Four houses disappeared to sea instantly with loss of two lives, as reported in the initial government dispatch.
• St. Lawrence: The telegraph office was found anchored in the middle of the harbour after being torn from its foundation.
• Lord's Cove: The telegraph office was totally destroyed, cutting off another critical communication link.
• Taylor's Bay: Sand deposits from the tsunami were later found 13 centimetres below the turf line by researchers studying past events.
• Garnish and areas east: Communications were completely cut off, with no initial particulars available from St. Lawrence to Garnish inclusive after the event.

The disaster was compounded the following day by a severe blizzard with sleet and snow. This storm hampered rescue efforts and worsened the plight of survivors. All means of communication were cut off by the destruction. The only telegraph line from the Burin Peninsula had gone out of service just prior to the earthquake. The peninsula was isolated from the outside world for days. The rest of the country did not learn the magnitude of the disaster until two and a half days later, on the morning of November 21, when a wireless message was sent via the S.S. Portia to St. John's.

Regional Effects and Tsunami Propagation

The tsunami's effects were felt far beyond the Burin Peninsula, demonstrating its transoceanic reach across the North Atlantic. To the west, the French islands of Saint Pierre and Miquelon were struck about 20 minutes after the earthquake at approximately 5:20 p.m., with waves submerging docks and flooding the lower parts of L'Île-aux-Marins, though no casualties were reported there and the quake's intensity on the islands was rated V to VI on the Rossi-Forel scale. The wave travelled across the Atlantic at remarkable speeds, its propagation strongly anisotropic due to ocean depth variations, reaching open ocean islands much faster than continental coasts because of deeper water pathways. It reached Bermuda, approximately 1,445 kilometres away, in just two hours, implying an average speed of about 700 km/h in the deep ocean, while taking 4.2 hours to reach Atlantic City at about 380 km/h and 2.7 hours to reach Halifax at roughly 230 km/h. The tsunami was recorded on tide gauges throughout the Atlantic, from Charleston, South Carolina, to the Azores in about four hours at a speed of 630 km/h, and as far as Lagos, Portugal, some 4,060 kilometres from the epicentre, where it was observed 6 hours and 47 minutes after the earthquake, confirming its energy travelled across the entire ocean basin.

The tsunami waves demonstrated varied travel times and speeds to different locations. It took 2 hours and 23 minutes for the tsunami to strike Burin, Newfoundland, which is 340 kilometres from the epicentre. The waves were observed in Bermuda, 1,445 kilometres away, in only about two hours. The waves reached the Azores in about 4 hours. Tsunami wave speeds were much slower in the direction of the North American coast. They required 2.7 hours to reach Halifax and 4.2 hours to reach Atlantic City. The tsunami was recorded as far away as Lagos, Portugal, 4,060 kilometres away, 6 hours and 47 minutes after the earthquake.

Relief Efforts and Aftermath

Isolation delayed the outside world's awareness of the catastrophe for two and a half days, with the first contact from outside occurring when a ship sailed into Burin and noticed nine buildings floating along the coast. The first official news did not reach the capital, St. John's, until the morning of November 21, via a wireless message sent from the S.S. Portia, describing the event as a 'bolt from the blue' in The Free Press newspaper. An immediate relief effort was organized, with the steamship S.S. Meigle dispatched from St. John's, arriving at Burin on the afternoon of November 22 with doctors, nurses, blankets, food, and other supplies after responding to an SOS from a passing ship. Recovery was slow and difficult, exacerbated by the destroyed infrastructure, the onset of winter, and the fact that every available cable ship in the Atlantic took almost a year to repair or replace the 12 damaged transatlantic telegraph cables, which had been critical for global communications. The prolonged cable repair operation itself became a notable maritime undertaking, while in the devastated communities, people struggled to rebuild their lives and livelihoods with the loss of homes, ships, businesses, livestock, and fishing gear.

Scientific Legacy and Discovery

The 1929 disaster gave birth to a major scientific discovery in marine geology that transformed understanding of underwater processes. By plotting this data, they deduced the path and speed of the powerful underwater current that had severed them, calculating it moved at speeds up to 100 km/h and identifying it as a previously poorly understood phenomenon. This work led to the first definitive documentation of a turbidity current and proved conclusively that the tsunami had been generated by the massive submarine landslide, not directly by the earthquake's fault rupture, solving a mystery that had persisted for over two decades. This revelation fundamentally changed the understanding of submarine geology and tsunami hazards, showing how large sediment deposits on continental slopes could fail and generate waves, with implications for coastal regions worldwide. Subsequent scientific studies have examined sediment layers along the Newfoundland coast, like those at Taylor's Bay found 13 centimetres below the turf, to establish a history of past tsunamis and determine the regional frequency of such large, landslide-triggered events, with the frequency influenced by sediment deposition offshore. The 1929 Grand Banks earthquake serves as a foundational case study in marine geohazards that continues to inform research on submarine landslides and their tsunami potential, with data archived by organizations like the National Centers for Environmental Information to support future hazard planning and mitigation.

Historical Context and Significance

The disaster struck Newfoundland at a precarious time, just as the Great Depression was beginning to take hold around the world, adding economic strain to physical devastation. The island was not yet part of Canada, remaining a British Dominion with an economy almost entirely dependent on the seasonal salt cod fishery centred on the Grand Banks, where the cold Labrador Current meets the warm Gulf Stream to create rich fishing grounds. The destruction of homes, boats, and fishing gear dealt a severe blow to countless families already living a near-subsistence existence in scattered communities along a coastline marked by many bays, inlets and small islands. The event highlighted the extreme vulnerability of isolated coastal communities to geophysical hazards and exposed critical gaps in communication and disaster response, with both land telegraphs and submarine cables severed, leaving no way to call for help. In modern terms, it demonstrated the necessity of tsunami education, early warning systems, and effective emergency communications for coastal regions, lessons that have informed later disaster preparedness planning. The 1929 Grand Banks earthquake and tsunami remains a defining event in Newfoundland's history, a tragic demonstration of nature's power that also unlocked seminal insights into the dynamic processes of the ocean floor and the generation of tsunamis from submarine landslides, bridging historical tragedy and scientific advancement.

Questions about 1929 Grand Banks earthquake

What caused the 1929 Grand Banks tsunami?

The tsunami was not directly caused by the earthquake itself but by an enormous submarine landslide that the earthquake triggered. The magnitude 7.2 quake destabilized sediments on the steep Laurentian Slope, causing an estimated 200 cubic kilometres of material to slump off the continental shelf. This massive displacement of the seafloor generated the tsunami waves that struck the coast about two and a half hours later. The landslide also created a fast-moving underwater mudflow called a turbidity current, which broke the transatlantic telegraph cables and was later studied to understand the event's dynamics and timing.

How many people died in the 1929 Grand Banks disaster?

The disaster resulted in 28 fatalities. Later historical research by scholars such as Alan Ruffman confirmed one additional death, bringing the official total to 28. This makes it the most tragic earthquake-related tsunami in Canadian history. The victims were primarily residents of small fishing communities on Newfoundland's Burin Peninsula like Kelly's Cove and Stepaside, where houses were swept out to sea instantly.

How high were the tsunami waves?

Tsunami wave heights varied significantly depending on the local coastline. Along the open shores of the Burin Peninsula, wave amplitudes were typically 3 to 8 metres. However, in the narrow, confined bays and inlets common to the area, the water piled up to much greater heights. The maximum recorded runup, the elevation the water reached above sea level, was 13 metres (approximately 43 feet). Specific reports from Burin mentioned an 'immense 15 foot tidal wave', and waves were observed as three main successive pulses over a period of about 30 minutes, with the first wave often being a trough.

Why was there a delay in help arriving after the tsunami?

Help was delayed for over three days due to a complete breakdown in communications. A storm had already knocked down the land telegraph lines connecting the Burin Peninsula just before the earthquake. The tsunami then destroyed coastal telegraph stations at St. Lawrence and Lord's Cove, with one office found anchored in the harbour. The submarine landslide also severed all 12 transatlantic telegraph cables in the area, cutting off marine communications. The outside world only learned of the disaster on November 21 when the S.S. Portia's wireless message reached St. John's. The S.S. Meigle arrived with aid on November 22 after responding to an SOS from a passing ship.

Was the tsunami felt outside of Newfoundland?

Yes, the tsunami had a transatlantic reach. It was recorded on tide gauges along the eastern coasts of Canada and the United States, including Halifax and Atlantic City. It travelled rapidly across the deep ocean, reaching Bermuda in about two hours and the Azores in about four hours. The waves were even recorded on the west coast of Portugal, approximately 4,060 kilometres from the epicentre, over six and a half hours after the earthquake. The nearby French islands of Saint Pierre and Miquelon were also flooded, with the wave reaching there about 20 minutes after the quake and submerging the docks.

What was the most important scientific discovery from this event?

The most important scientific discovery was the first definitive documentation of a turbidity current. In 1952, scientists from Columbia University studied the sequentially broken submarine telegraph cables. By analysing the order and timing of the cable breaks, they mapped the path and speed of an enormous underwater flow of mud and sand. This proved the tsunami was triggered by a large submarine landslide, not directly by the earthquake's fault movement. This work founded the modern scientific study of turbidity currents. It transformed the understanding of how underwater landslides can generate major tsunamis, making the 1929 event a foundational case study in marine geology.

Sources and further reading

• 1929 Grand Banks earthquake (Wikipedia)
• 18 November 1929, Mw 7.2, Newfoundland, Canada (legacy.itic.ioc-unesco.org)
• On This Day: 1929 Grand Banks Tsunami | News (ncei.noaa.gov)
• 18 November 1929, Mw 7.2, Newfoundland, Canada (tsunami.ioc.unesco.org)

Checked by the Your Space Hamilton desk. Last updated 2026-10-27.