The 1946 Vancouver Island earthquake struck

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian Provinces and territories of Canada, province of British Columbia. The island is in length, in width at its widest point, and in total area, while are o ...

on the

coast of British Columbia , settlement_type = Region of British Columbia , image_skyline = , nickname = "The Coast" , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 = British ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, on June 23 at 10:15 a.m. with a magnitude estimated at 7.0 and 7.5 . The main shock

epicenter The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

occurred in the

Forbidden Plateau The Forbidden Plateau is a small, hilly plateau in the east of the Vancouver Island Vancouver Island Ranges, Ranges in British Columbia, northwest of Comox Lake roughly between Mount Albert Edward (British Columbia), Mount Albert Edward to the sou ...

area northwest of Courtenay. While most of the large earthquakes in the

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

area occur at

tectonic plate Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

boundaries, the 1946 Vancouver Island earthquake was a crustal event. Shaking was felt from

Portland, Oregon Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populous co ...

, to

Prince Rupert, British Columbia Prince Rupert is a port city in the province of British Columbia, Canada. Its location is on Kaien Island near the Alaskan panhandle. It is the land, air, and water transportation hub of British Columbia's North Coast, and has a population of 12, ...

. This is one of the most damaging earthquakes in the history of British Columbia, but damage was restricted because there were no heavily populated areas near the epicentre, where severe shaking occurred. This earthquake is Canada's largest historic onshore earthquake.The M7.3 Vancouver Island Earthquake of 1946
Retrieved on 2008-06-11 However, the greatest earthquake in Canadian history recorded by

seismometer A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The outpu ...

s was the 1949 Queen Charlotte earthquake, an

interplate earthquake An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates. Earthquakes of this type account for more than 90 percent of the total seismic energy released around the world. If one plate is trying to move past ...

that occurred on the ocean bottom just off the rugged coast of

Graham Island Graham Island () is the largest island in the Haida Gwaii archipelago (previously known as the Queen Charlotte Islands), lying off the mainland coast of British Columbia, Canada. It is separated by the narrow Skidegate Channel from the other pri ...

, which reached magnitude 8.1 on the

moment magnitude scale The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...

Background and tectonics

The

tectonics Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents k ...

that caused the 1946 Vancouver Island earthquake are poorly known. No surface expression of the offset was noticed, most likely because the epicenter area is very remote and densely forested. A comprehensive examination and computer interpretation of seismic data from over 50 stations have shown that a possible explanation of the earthquake includes a

strike-slip fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

corresponding to the lengthy axis of Vancouver Island, known as the

Beaufort Range The Beaufort Range is a mountain range on southern Vancouver Island, British Columbia, Canada, located north of Port Alberni and to the west of Qualicum Beach, and running from Horne Lake in the southeast to Comox Lake in the northwest. It has a ...

Fault. A fault running across Vancouver Island, corresponding to the projection of the underwater

Nootka Fault The Nootka Fault is an active transform fault running southwest from Nootka Island, near Vancouver Island, British Columbia, Canada. Geology The Nootka Fault lies between the Explorer Plate in the north and Juan de Fuca Plate in south. These a ...

on the

British Columbia Coast , settlement_type = Region of British Columbia , image_skyline = , nickname = "The Coast" , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 = British ...

, is also a possibility but an unlikely one because the earthquake showed no evidence of offsets along with a series of highways that follows much of the eastern coastline of Vancouver Island, called

Island Highway The Island Highway is actually a series of highways that follows much of the eastern coastline of Vancouver Island, British Columbia, Canada. While the Island Highway has no officially designated starting point, it is understood to begin at the ...

, and other roads between Courtenay and Campbell River. The estimated depth of the earthquake places it within the

continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called ''sial'' be ...

, not at the margin with the

Cascadia subduction zone The Cascadia subduction zone is a convergent plate boundary that stretches from northern Vancouver Island in Canada to Northern California in the United States. It is a very long, sloping subduction zone where the Explorer, Juan de Fuca, and ...

, and certainly not inside the subduction zone itself. Specifically, the earthquake's epicenter was positioned somewhere in the

region, in central

Damage and casualties

Though very destructive, the earthquake caused only two deaths: Jacob L. Kingston, aged 69, and Daniel Fidler, who was 50. Kingston suffered a heart attack in

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

, while Fidler drowned when his

dinghy A dinghy is a type of small boat, often carried or towed by a larger vessel for use as a tender. Utility dinghies are usually rowboats or have an outboard motor. Some are rigged for sailing but they differ from sailing dinghies, which ...

was swamped by a wave. In

, damage consisted of lofty buildings oscillating violently, and a piece of masonry fell from the local railway station. In addition, within the city, at least one gas line cracked and several power outages occurred. Fires broke out in several chimneys, and at least one swing-span bridge was fractured by the shaking. In the Hotel Vancouver, which housed the elderly and caught on fire, more than 500 war veterans' families fled the flames. One writer, George Finley, stated that the

Lions' Gate Bridge The Lions Gate Bridge, opened in 1938 and officially known as the First Narrows Bridge, is a suspension bridge that crosses the first narrows of Burrard Inlet and connects the City of Vancouver, British Columbia, to the North Shore municipali ...

"swayed like a leaf", coinciding with a "low, rumbling sound, like a deep growl." Bank of Montreal damage in 1946

The 1946 Vancouver Island earthquake demolished 75% of the chimneys in the communities of

Cumberland Cumberland ( ) is a historic county in the far North West England. It covers part of the Lake District as well as the north Pennines and Solway Firth coast. Cumberland had an administrative function from the 12th century until 1974. From 19 ...

, Union Bay, and Courtenay and caused extensive damage in Comox,

Port Alberni Port Alberni () is a city located on Vancouver Island in the province of British Columbia, Canada. The city lies within the Alberni Valley at the head of the Alberni Inlet, Vancouver Island's longest inlet. It is the location of the head offices o ...

, and Powell River, on the eastern side of the

Strait of Georgia The Strait of Georgia (french: Détroit de Géorgie) or the Georgia Strait is an arm of the Salish Sea between Vancouver Island and the extreme southwestern mainland coast of British Columbia, Canada and the extreme northwestern mainland coast ...

. Some chimneys were fractured in

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

, and people in Victoria and Vancouver experienced great fright, with some seen fleeing into the streets.

Landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of ...

s created by the earthquake were common throughout Vancouver Island. Land subsidence resulted from the earthquake, most commonly around shorelines on the Strait of Georgia. This included the bottom of Deep Bay which sank between and . These measurements were reported by the

Canadian Hydrographic Service ''Retired Canadian Hydrographic Service logo or crest'' The Canadian Hydrographic Service (CHS) is part of the federal department of Fisheries and Oceans Canada and is Canada's authoritative hydrographic office. The CHS represents Canada in t ...

. Also, a ground shift occurred on

Read Island Read Island is an island in British Columbia, Canada. It is part of the Discovery Islands between Vancouver Island and the mainland, between the Strait of Georgia and Johnstone Strait. Etymology Read Island was named around 1864 by Daniel Pender ...

. Ships throughout the region were affected, and those on board them during the earthquake described it as similar to having run over a

sand bar In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It o ...

or striking a rock. Undersea power lines were destroyed in the long narrow

Alberni Inlet Alberni Inlet (formerly known as Alberni Canal) is a long, narrow inlet in Vancouver Island, British Columbia, Canada, that stretches from the Pacific Ocean at Barkley Sound about inland terminating at Port Alberni. It was named by the Spanish ex ...

and near the city of Powell River. All lighthouse keepers in the surrounding area felt the earthquake, and experienced damage including shattered windows and smashed dishes. A

tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explo ...

struck the west coast of

Texada Island Texada Island is a large island located in the Strait of Georgia of British Columbia, Canada. With an area of , it is the largest island of the Gulf Islands and the third largest island in the Strait of Georgia after Whidbey Island in Washington a ...

with two waves, the first being high and the second high. The earthquake caused a landslide near Mount Colonel Foster. One fortunate occurrence allowed researchers afterward to review the effects of the earthquake: an aerial photographic survey of Vancouver Island had commenced in 1946, soon after the earthquake, and these photographs were eventually studied by a geoscientist in the late 1970s. South of the Canada–United States border in

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington ...

, some chimneys fell at Eastsound on

Orcas Island Orcas Island () is the largest of the San Juan Islands of the Pacific Northwest, which are in the northwestern corner of San Juan County, Washington. History and naming of the island The name "Orcas" is a shortened form of ''Horcasitas,'' fro ...

and a concrete mill was damaged at

Port Angeles Port Angeles ( ) is a city and county seat of Clallam County, Washington, United States. With a population of 19,960 as of the 2020 census, it is the largest city in the county. The population was estimated at 20,134 in 2021. The city's har ...

. In

, some damage occurred on upper floors of tall buildings that had visibly swayed. The

expansion joint An expansion joint, or movement joint, is an assembly designed to hold parts together while safely absorbing temperature-induced expansion and contraction of building materials, and vibration, or to allow movement due to ground settlement or seis ...

s on a bridge on

U.S. Highway 10 U.S. Route 10 or U.S. Highway 10 (US 10) is an east–west United States highway located in the Midwest and Great Lakes regions of the United States. Unlike most U.S. routes with "0" as the last digit of its route number, US 10 ...

near

Mercer Island Mercer Island is a city in King County, Washington, United States, located on an island of the same name in the southern portion of Lake Washington. Mercer Island is in the Seattle metropolitan area, with Seattle to its west and Bellevue to it ...

were also damaged by the earthquake. The shock was strongly felt at Bellingham, Everett,

Olympia The name Olympia may refer to: Arts and entertainment Film * ''Olympia'' (1938 film), by Leni Riefenstahl, documenting the Berlin-hosted Olympic Games * ''Olympia'' (1998 film), about a Mexican soap opera star who pursues a career as an athlet ...

Raymond Raymond is a male given name. It was borrowed into English from French (older French spellings were Reimund and Raimund, whereas the modern English and French spellings are identical). It originated as the Germanic ᚱᚨᚷᛁᚾᛗᚢᚾᛞ ( ...

, and Tacoma. A , crack in the glacier covering

Big Four Mountain Big Four is a mountain summit in the Cascade Range, located about east of Granite Falls, Washington. It is situated west of Barlow Pass along the Mountain Loop Highway, near the Monte Cristo area, on land administered by the Mount Baker-Sn ...

Snohomish County, Washington Snohomish County () is a county located in the U.S. state of Washington. With a population of 827,957 as of the 2020 census, it is the third-most populous county in Washington, after nearby King and Pierce counties, and the 75th-most populous ...

, was created by the earthquake. The earthquake was powerful enough to knock the needle off a

seismograph A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output ...

at the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...

, and was sustained for about a minute even in Seattle. The earthquake caused significant movement among structures, moving one wall about and caused one home to shift for off its foundation. The total affected area in Canada and the United States was about .

References

External links

* {{DEFAULTSORT:Vancouver Island 1946 in Canada 1946 natural disasters in the United States 1946 Vancouver 1946 earthquakes History of Vancouver Island 1946 Vancouver Alberni Valley 1946 in British Columbia 1946 in Washington (state) 1946 disasters in Canada

Background and tectonics

Damage and casualties

See also

References

External links