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, a ...
on January 26, 1700, with an estimated
moment magnitude
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 ...
of 8.7–9.2. The
megathrust earthquake
Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthqua ...
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 ...
, south along the
Pacific Northwest
The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...
coast as far as
northern California
Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...
. The length of the fault rupture was about , with an average slip of .
The earthquake caused 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 ...
which struck the west coast of North America and the coast of
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. Japanese tsunami records, along with reconstructions of the wave moving across the ocean, put the earthquake at about 9pm on the evening of 26 January 1700.
Evidence
The earthquake took place at about 21:00
Pacific Time
The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time ( UTC−08:00). ...
on January 26, 1700 ( NS). Although there are no written records for the region from the time, the timing of the earthquake has been inferred from Japanese records of a tsunami that does not correlate with any other
Pacific Rim
The Pacific Rim comprises the lands around the rim of the Pacific Ocean. The ''Pacific Basin'' includes the Pacific Rim and the islands in the Pacific Ocean. The Pacific Rim roughly overlaps with the geologic Pacific Ring of Fire.
List of co ...
quake. The Japanese records exist primarily in the modern-day
Iwate Prefecture
is a prefecture of Japan located in the Tōhoku region of Honshu. It is the second-largest Japanese prefecture at , with a population of 1,210,534 (as of October 1, 2020). Iwate Prefecture borders Aomori Prefecture to the north, Akita Prefectur ...
Ōtsuchi
An is a large wooden war mallet used by the samurai class of feudal Japan. The ōtsuchi had a shaft of about much like the ono (war axe). It was mainly used for door breaching
Door breaching is a process used by military, police, or emerg ...
.
Scientific research
The most important clue linking the tsunami in Japan and the earthquake in the Pacific Northwest comes from studies of tree rings (
dendrochronology
Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed. As well as dating them, this can give data for dendroclimatology, the study of climate and atmos ...
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
and
Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
, killed by lowering of coastal forests into the tidal zone by the earthquake, have outermost growth rings that formed in 1699, the last growing season before the tsunami. This includes both inland stands of trees, such as one on the Copalis River in Washington, and pockets of tree stumps that are now under the ocean surface and become exposed only at low tide."Jan. 26, 1700: How Scientists Know When The Last Big Earthquake Happened Here"
Oregon Public Broadcasting
Oregon Public Broadcasting (OPB) is the primary television and radio public broadcasting network for most of the U.S. state of Oregon as well as southern Washington. OPB consists of five full-power television stations, dozens of VHF or UHF tra ...
, January 26, 2015.
Sediment layers in these locations demonstrate a pattern consistent with seismic and tsunami events around this time. Core samples from the ocean floor, as well as debris samples from some earthquake-induced
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 in the Pacific Northwest, also support this timing of the event. Archaeological research in the region has uncovered evidence of several coastal villages having been flooded and abandoned around 1700.
Cultural research
The contemporary indigenous groups of Cascadia had no known written documentation like that of the Japanese tsunami, but numerous
oral tradition
Oral tradition, or oral lore, is a form of human communication wherein knowledge, art, ideas and cultural material is received, preserved, and transmitted orally from one generation to another. Vansina, Jan: ''Oral Tradition as History'' (1985 ...
s describing a great earthquake and inundation exist among indigenous coastal peoples from British Columbia to Northern California. These do not specify a date, and not all earthquake stories in the region can be ascribed to the 1700 quake; however, virtually all of the native peoples in the region have at least one traditional story of an event of unmatched destructive power.
Some of the stories contain temporal clues — such as a time estimate in
generation
A generation refers to all of the people born and living at about the same time, regarded collectively. It can also be described as, "the average period, generally considered to be about 20–30 years, during which children are born and gr ...
s since the event — which suggest a date range in the late 1600s or early 1700s, or which concur with the event's timing in other ways. For instance, the Huu-ay-aht legend of a large earthquake and ocean wave devastating their settlements at Pachena Bay places the event on a winter evening shortly after the village's residents had gone to sleep (consistent with the 9pm reconstructed time). Every community on Pachena Bay was wiped out except for Masit on a mountainside above sea level. The only other survivor was Anacla aq sop, a young woman who happened to be staying that day at Kiix-in on the more tsunami-sheltered
Barkley Sound
, image = Fishing boat in the Broken Group Islands.jpg
, image_size = 260px
, alt =
, caption = Barkley Sound
, image_bathymetry =
, alt_bathymetry =
, caption_bathymetry =
, locat ...
.
Kwakwaka'wakw (Kwakiutl) stories from the north end of Vancouver Island report a night-time earthquake that caused virtually all houses in their community to collapse;Cowichan stories from Vancouver Island's inner coast speak of a nighttime earthquake, causing a
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 ...
that buried an entire village.
Makah
The Makah (; Klallam: ''màq̓áʔa'')Renker, Ann M., and Gunther, Erna (1990). "Makah". In "Northwest Coast", ed. Wayne Suttles. Vol. 7 of '' Handbook of North American Indians'', ed. William C. Sturtevant. Washington, D.C.: Smithsonian Instit ...
stories from Washington speak of a great night-time earthquake, of which the only survivors were those who fled inland before the tsunami hit. The
Quileute
The Quileute , are a Native American people in western Washington state in the United States, currently numbering approximately 2,000. They are a federally recognized tribe: the ''Quileute Tribe of the Quileute Reservation''.
The Quileute peo ...
people in Washington have a story about a flood so powerful that villagers in their canoes were swept inland all the way to
Indian Country Today Media Network
''ICT News'' (formerly known as ''Indian Country Today'') is a daily digital news platform that covers the Indigenous world, including American Indians, Alaska Natives and First Nations.
It was founded in 1981 as a weekly print newspaper, ''The ...
'', November 6, 2012.
Ethnographic
Ethnography (from Greek ''ethnos'' "folk, people, nation" and ''grapho'' "I write") is a branch of anthropology and the systematic study of individual cultures. Ethnography explores cultural phenomena from the point of view of the subject ...
research has focused on a common regional pattern of art and
mythology
Myth is a folklore genre consisting of narratives that play a fundamental role in a society, such as foundational tales or origin myths. Since "myth" is widely used to imply that a story is not objectively true, the identification of a narrat ...
depicting a great battle between a
thunderbird
Thunderbird, thunder bird or thunderbirds may refer to:
* Thunderbird (mythology), a legendary creature in certain North American indigenous peoples' history and culture
* Ford Thunderbird, a car
Birds
* Dromornithidae, extinct flightless birds ...
and a
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
, as well as cultural signifiers such as earthquake-inspired ritual masks and dances.
Future threats
The geological record reveals that "great earthquakes" (those with
moment magnitude
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 ...
8 or higher) occur in 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, a ...
about every 500 years on average, often accompanied by
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 ...
s. There is evidence of at least 13 events at intervals from about 300 to 900 years with an average of 570–590 years. Previous earthquakes are estimated to have been in AD 1310, AD 810, AD 400, 170 BC and 600 BC.
As seen in the 1700 quake, the
2004 Indian Ocean earthquake
An earthquake and a tsunami, known as the Boxing Day Tsunami and, by the scientific community, the Sumatra–Andaman earthquake, occurred at 07:58:53 local time (UTC+7) on 26 December 2004, with an epicentre off the west coast of northern Suma ...
, and the
2011 Tōhoku earthquake and tsunami
The occurred at 14:46 JST (05:46 UTC) on 11 March. The magnitude 9.0–9.1 (M) undersea megathrust earthquake had an epicenter in the Pacific Ocean, east of the Oshika Peninsula of the Tōhoku region, and lasted approximately six minutes ...
, subduction zone earthquakes can cause large tsunamis, and many coastal areas in the region have prepared tsunami evacuation plans in anticipation of a possible future Cascadia earthquake. However, the major nearby cities, notably
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 ...
,
Portland
Portland most commonly refers to:
* Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States
* Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...
,
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 ...
,
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 Tacoma, which are located on inland waterways rather than on the coast, would be sheltered from the full brunt of a tsunami. These cities do have many vulnerable structures, especially bridges and unreinforced brick buildings; consequently, most of the damage to the cities would probably be from the earthquake itself. One expert asserts that buildings in Seattle are vastly inadequate even to withstand an event of the size of the
1906 San Francisco earthquake
At 05:12 Pacific Standard Time on Wednesday, April 18, 1906, the coast of Northern California was struck by a major earthquake with an estimated moment magnitude of 7.9 and a maximum Mercalli intensity of XI (''Extreme''). High-intensity sha ...
, let alone any more powerful one.
Kenneth Murphy, who directs
FEMA
The Federal Emergency Management Agency (FEMA) is an agency of the United States Department of Homeland Security (DHS), initially created under President Jimmy Carter by Presidential Reorganization Plan No. 3 of 1978 and implemented by two Ex ...
's Region X, the division responsible for Oregon, Washington, Idaho, and Alaska, put it quite dramatically: "Our operating assumption is that everything west of
Interstate 5
Interstate 5 (I-5) is the main north–south Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels through the states of Californi ...
will be toast."
Recent findings conclude that the Cascadia subduction zone is more complex and volatile than previously believed. In 2010, geologists predicted a 37% chance of an M8.2+ event within 50 years, and a 10 to 15% chance that the entire Cascadia subduction zone will rupture with an M9+ event within the same time frame. Geologists have also determined the Pacific Northwest is not prepared for such a colossal quake. The tsunami produced could reach heights of .
A 2004 study revealed the potential for relative mean
sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
(caused by subsidence) along the Cascadia subduction zone. It postulated that cities on the west coast of Vancouver Island, such as
Tofino
Tofino ( ) is a town of approximately 2,516 residents on the west coast of Vancouver Island in the Canadian province of British Columbia. The District of Tofino is located at the western terminus of Highway 4 on the tip of the Esowista Peninsu ...
and
Ucluelet
Ucluelet (, also Ukee) is a district municipality (population 1,717) on the Ucluelet Peninsula on the west coast of Vancouver Island in British Columbia, Canada. Ucluelet means "people of the safe harbour" in the indigenous Nuu-chah-nulth (No ...
, are at risk for a 1–2 m subsidence, relative to mean sea level.
The confirmation of their oral traditions about a great earthquake has led many aboriginal groups in the area to initiate projects to relocate their coastal communities to higher and safer ground in preparation for the predicted next earthquake. The Huu-ay-aht People have rebuilt their administration building on a high point of land in their territory; coastal residents are immediately evacuated to this building whenever a tsunami warning is issued, as an interim measure toward eventually relocating all residents to higher ground. The
Quileute
The Quileute , are a Native American people in western Washington state in the United States, currently numbering approximately 2,000. They are a federally recognized tribe: the ''Quileute Tribe of the Quileute Reservation''.
The Quileute peo ...
people secured a land grant from the federal government of the United States in 2012 to move their settlement inland, both as protection from a future tsunami threat and because of more frequent flooding on the
Quillayute River
The Quillayute River (also spelled Quileute River) is a river situated on the Olympic Peninsula in Washington. It empties to the Pacific Ocean at La Push, Washington. The Quillayute River is formed by the confluence of the Bogachiel River, Cal ...
. The Shoalwater Bay Indian Tribe has also set a goal of moving their community uphill and has received a FEMA PDM grant to build the first vertical evacuation tower on their coast, scheduled to be completed near the Tokeland Marina by 2022.
Some other subduction zones have such earthquakes every 100 to 200 years; the longer interval results from slower plate motions. The rate of convergence between the Juan de Fuca Plate and the
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...
Tseax Cone
The Tseax Cone ( ), also called the Tseax River Cone or the Aiyansh Volcano, is a young and active cinder cone and adjacent lava flows associated with the Nass Ranges and the Northern Cordilleran Volcanic Province. It is located east of Crater ...
eruption in British Columbia, Canada. However, recent investigations using radiocarbon dating and dendrochronology date the Bonneville landslide around 1450.
Geology of the Pacific Northwest
The geology of the Pacific Northwest includes the composition (including rock, minerals, and soils), structure, physical properties and the processes that shape the Pacific Northwest region of North America. The region is part of the Ring of F ...
*
List of earthquakes in Canada
This is a list of earthquakes in Canada.
List
Abbreviations used:
See also
*Hydraulic fracturing in Canada
References
External links
*Natural Resources CanadEarthquakes Canada*Earthquakes CanadRecent earthquakes
{{DEFAULTSORT:Earthquake ...
List of historical earthquakes
Historical earthquakes is a list of significant earthquakes known to have occurred prior to the beginning of the 20th century. As the events listed here occurred before routine instrumental recordings, they rely mainly on the analysis of written ...
*
List of tsunamis
This article lists notable tsunamis, which are sorted by the date and location that the tsunami occurred.
Because of seismic and volcanic activity associated with tectonic plate boundaries along the Pacific Ring of Fire, tsunamis occur most fr ...
*
Lists of earthquakes
Earthquakes are caused by movements within the Earth's crust and uppermost mantle. They range from events too weak to be detectable except by sensitive instrumentation, to sudden and violent events lasting many minutes which have caused some of ...
Pacific Tsunami Warning Center
The Pacific Tsunami Warning Center (PTWC) is one of two tsunami warning centers that are operated by NOAA in the United States. Headquartered on Ford Island, HI, the PTWC is part of an international tsunami warning system (TWS) program and s ...
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
Journal of Geophysical Research
The ''Journal of Geophysical Research'' is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the un ...
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
The Oregonian
''The Oregonian'' is a daily newspaper based in Portland, Oregon, United States, owned by Advance Publications. It is the oldest continuously published newspaper on the U.S. west coast, founded as a weekly by Thomas J. Dryer on December 4, 185 ...