The 1870 Charlevoix earthquake occurred on 20 October in the Canadian province of
Quebec
Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...
. It had a
moment magnitude
The moment magnitude scale (MMS; denoted explicitly with or Mwg, 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. was defined in a 1979 paper ...
of 6.6 and a
Modified Mercalli intensity rating of X (''Extreme''). The town of
Baie-Saint-Paul
Baie-Saint-Paul (; 2021 Population 7,371; UA population 4,308) is a city in the Province of Quebec, Canada, on the northern shore of the St. Lawrence River. Baie-Saint-Paul is the seat of Charlevoix Regional County Municipality. The city i ...
was seriously damaged by the event, with the loss of six lives. Effects from the earthquake were felt as far as
Virginia
Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...
and along the
New England
New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...
coast of the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
.
Tectonic setting
The
Charlevoix Seismic Zone (CSZ) lies along the St. Lawrence River, northeast of Quebec City. Although eastern Canada has relatively infrequent earthquakes, due to its location away from active plate boundaries, the CSZ is its most active part, with five earthquakes of an estimated magnitude of 6 or greater since historical records began.
Focal mechanism
The focal mechanism of an earthquake describes the Fault (geology)#Slip.2C heave.2C throw, deformation in the Hypocenter, source region that generates the seismic waves. In the case of a Fault (geology), fault-related event, it refers to the ori ...
s for earthquakes in this zone are consistent with rupture on both
reverse and strike-slip faults. The main structures of the area are faults of the
Saint Lawrence rift system that run parallel to the river, formed during the break-up of the
supercontinent
In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...
Rodinia
Rodinia (from the Russian родина, ''rodina'', meaning "motherland, birthplace") was a Mesoproterozoic and Neoproterozoic supercontinent that assembled 1.26–0.90 billion years ago (Ga) and broke up 750–633 million years ago (Ma). wer ...
in the late
Neoproterozoic
The Neoproterozoic Era is the last of the three geologic eras of the Proterozoic geologic eon, eon, spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era an ...
and early
Paleozoic
The Paleozoic ( , , ; or Palaeozoic) Era is the first of three Era (geology), geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma a ...
. The greatest seismicity occurs where the rift is overprinted by a ~300 Ma meteorite impact structure, the
Charlevoix impact structure
The Charlevoix impact structure is a large eroded meteorite impact structure in the Charlevoix region of Quebec, Canada. Only part of the impact structure is exposed at the surface, the rest lying beneath the Saint Lawrence River.
Description
...
. Most CSZ earthquakes have
hypocenter
A hypocenter or hypocentre (), also called ground zero or surface zero, is the point on the Earth's surface directly below a nuclear explosion, meteor air burst, or other mid-air explosion. In seismology, the hypocenter of an earthquake is its ...
s within the
Grenvillian basement
A basement is any Storey, floor of a building that is not above the grade plane. Especially in residential buildings, it often is used as a utility space for a building, where such items as the Furnace (house heating), furnace, water heating, ...
at depths between 7 and 15 km. Many of the smaller earthquakes do not appear to be located on the rift faults but within the volumes of rock between them. Larger events lie outside the impact structure and have inferred nodal planes consistent with reactivation of the rift faults. The relatively weak impact structure is interpreted to cause a perturbation of the regional stress field, affecting the stability of the rift faults.
The estimated length of the most active portion of the CSZ is . The total fault area is determined to be .
Earthquake
The shallow-focus earthquake had an epicenter around the
Saint Lawrence River
The St. Lawrence River (, ) is a large international river in the middle latitudes of North America connecting the Great Lakes to the North Atlantic Ocean. Its waters flow in a northeasterly direction from Lake Ontario to the Gulf of St. Lawrenc ...
. Its epicenter has been suggested to be in the southwestern end of the CSZ. A maximum Mercalli intensity of IX–X (''Violent–Extreme'') was assigned to Baie-Saint-Paul. In
Quebec City
Quebec City is the capital city of the Provinces and territories of Canada, Canadian province of Quebec. As of July 2021, the city had a population of 549,459, and the Census Metropolitan Area (including surrounding communities) had a populati ...
, the intensity is estimated at VI (''Strong''). In
Old Montreal
Old Montreal (, ) is a historic List of neighbourhoods in Montreal, neighbourhood within the List of municipalities in Quebec, municipality of Montreal in the province of Quebec, Canada. Home to the Old Port of Montreal, the neighbourhood is b ...
, strong to damaging (VI–VII) levels of shaking was observed. Researcher John E. Ebel and others calculated the intensity magnitude of the earthquake at 5.5–6.0, with 5.8 being the best estimate.
Meanwhile, the
Geological Survey of Canada
The Geological Survey of Canada (GSC; , CGC) is a Canadian federal government agency responsible for performing geological surveys of the country developing Canada's natural resources and protecting the environment. A branch of the Earth Science ...
and
U.S. Geological Survey
The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on March ...
earthquake catalogs placed the moment magnitude at 6.6 .
Damage
Two children lost their lives in the
Les Éboulements
Les Éboulements () is a municipality (Quebec), municipality in the Capitale-Nationale region of Quebec, Canada.
Its population centres include Les Éboulements (located along Quebec Route 362, Route 362 on the plateau overlooking the Saint Lawr ...
municipality in
Capitale-Nationale
Capitale-Nationale (; ) is one of the 17 administrative regions of Quebec. It is anchored by the provincial capital, Quebec City, and is largely coextensive with that city's metropolitan area. It has a land area of 18,684.78 km2. It reported ...
. Four additional deaths were attributed to a
landslide
Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...
five days later. Despite the size and intensity of the quake, few deaths occurred due to the sparse population during the time of the quake.
Liquefaction
In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics.
It occurs both naturally and artificially. As an example of t ...
occurred in the affected area. A landslide may have also occurred in the
Saguenay River
__NOTOC__
The Saguenay River (, ) is a major river of Quebec, Canada.
It drains Lac Saint-Jean in the Laurentian Highlands, leaving at Alma and running east; the city of Saguenay is located on the river. It drains into the Saint Lawrence River. ...
. Many homes in Les Éboulements were destroyed.
Saint-Roch was severely damaged by the quake as well.
Many chimneys were damaged in Lower Quebec City.
In
Portland, Maine
Portland is the List of municipalities in Maine, most populous city in the U.S. state of Maine and the county seat, seat of Cumberland County, Maine, Cumberland County. Portland's population was 68,408 at the 2020 census. The Portland metropolit ...
, the windows of buildings shattered. A rumbling sound was heard at
Albany, New York
Albany ( ) is the List of capitals in the United States, capital city of the U.S. state of New York (state), New York. It is located on the west bank of the Hudson River, about south of its confluence with the Mohawk River. Albany is the oldes ...
, which lasted up to a minute. Clocks stopped in
Cleveland, Ohio
Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County, Ohio, Cuyahoga County. Located along the southern shore of Lake Erie, it is situated across the Canada–United States border, Canada–U.S. maritime border ...
. Reports of the earthquake's effects in
Dubuque, Iowa
Dubuque (, ) is a city in Dubuque County, Iowa, United States, and its county seat. The population was 59,667 at the 2020 United States census. The city lies along the Mississippi River at the junction of Iowa, Illinois, and Wisconsin, a region ...
and
Richmond, Virginia
Richmond ( ) is the List of capitals in the United States, capital city of the Commonwealth (U.S. state), U.S. commonwealth of Virginia. Incorporated in 1742, Richmond has been an independent city (United States), independent city since 1871. ...
have been taken with skepticism.
See also
*
List of earthquakes in Canada
*
List of earthquakes in the United States
The following is a list of notable earthquakes and tsunamis which had their epicenter in areas that are now part of the United States with the latter affecting areas of the United States. Those in ''italics'' were not part of the United States wh ...
*
1663 Charlevoix earthquake
The 1663 Charlevoix earthquake occurred on February 5 in New France (now the Canadian province of Quebec), and was assessed to have a moment magnitude of between 7.3 and 7.9. The earthquake occurred at 5:30 p.m. local time and was estimated ...
*
Charlevoix Seismic Zone
References
;Bibliography
*
{{Earthquakes in the United States
1870 natural disasters
1870 in Canada
1870 earthquakes
Baie-Saint-Paul
Earthquakes in Quebec
1870 in Quebec