1700 Cascadia earthquake

Last updated
1700 Cascadia earthquake
North America laea relief location map with borders.jpg
Bullseye1.png
USGS-ANSS ComCat
Local dateJanuary 26, 1700 (1700-01-26)
Local time21:00 local time [1]
Magnitude8.7–9.2 Mw [2]
Epicenter 45°N125°W / 45°N 125°W / 45; -125 Coordinates: 45°N125°W / 45°N 125°W / 45; -125 [1]
Fault Cascadia subduction zone
Type Megathrust
TsunamiYes

The 1700 Cascadia earthquake occurred along the Cascadia subduction zone on January 26, 1700, with an estimated moment magnitude of 8.7–9.2. The megathrust earthquake involved the Juan de Fuca Plate from mid-Vancouver Island, south along the Pacific Northwest coast as far as northern California. The length of the fault rupture was about 1,000 kilometers (620 miles), with an average slip of 20 meters (66 ft).

Contents

The earthquake caused a tsunami which struck the west coast of North America and the coast of Japan. [3] 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. [4]

Cascadia subduction zone Cascadia subduction zone USGS.png
Cascadia subduction zone

Evidence

The earthquake took place at about 21:00 Pacific Time 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 quake. The Japanese records exist primarily in the modern-day Iwate Prefecture, in communities such as Tsugaruishi, Miyako (Kuwagasaki) and Ōtsuchi. [4]

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), which show that several "ghost forests" of red cedar trees in Oregon and Washington, 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. [5] This includes both inland stands of trees, such as one on the Copalis River in Washington, [5] and pockets of tree stumps that are now under the ocean surface and become exposed only at low tide. [6]

Sediment layers in these locations demonstrate a pattern consistent with seismic and tsunami events around this time. [7] Core samples from the ocean floor, as well as debris samples from some earthquake-induced landslides in the Pacific Northwest, also support this timing of the event. [6] Archaeological research in the region has uncovered evidence of several coastal villages having been flooded and abandoned around 1700. [8]

Cultural research

The contemporary indigenous groups of Cascadia had no written documentation like that of the Japanese tsunami, but numerous oral traditions describing a great earthquake and inundation exist among indigenous coastal peoples from British Columbia to Northern California. [5] [9] 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 generations since the event [8] — which suggest a date range in the late 1600s or early 1700s, [5] 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). [10] Every community on Pachena Bay was wiped out except for Masit on a mountainside 75 feet (23 m) above sea level. [11] 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.

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; [8] Cowichan stories from Vancouver Island's inner coast speak of a nighttime earthquake, causing a landslide that buried an entire village. [8] Makah stories from Washington speak of a great night-time earthquake, of which the only survivors were those who fled inland before the tsunami hit. [12] The Quileute people in Washington have a story about a flood so powerful that villagers in their canoes were swept inland all the way to Hood Canal. [13]

Ethnographic research has focused on a common regional pattern of art and mythology depicting a great battle between a thunderbird and a whale, [8] as well as cultural signifiers such as earthquake-inspired ritual masks and dances. [14]

Future threats

Earthquake recurrence
est. yearinterval
(years)
1700 AD> 322
1310 AD390
810 AD500
400 AD410
170 BC570
600 BC430

The geological record reveals that "great earthquakes" (those with moment magnitude 8 or higher) occur in the Cascadia subduction zone about every 500 years on average, often accompanied by tsunamis. There is evidence of at least 13 events at intervals from about 300 to 900 years with an average of 570–590 years. [15] Previous earthquakes are estimated to have been in 1310 AD, 810 AD, 400 AD, 170 BC and 600 BC.

Cascadia earthquake sources Cascadia earthquake sources.png
Cascadia earthquake sources
A scenario of a magnitude 9.0 earthquake on the Cascadia subduction zone by the United States Geological Survey. 9.0 Cascadia scenario (median).pdf
A scenario of a magnitude 9.0 earthquake on the Cascadia subduction zone by the United States Geological Survey.

As seen in the 1700 quake, the 2004 Indian Ocean earthquake, and the 2011 Tōhoku earthquake and tsunami, 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, Portland, Vancouver, Victoria, 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, let alone any more powerful one. [16]

Kenneth Murphy, who directs FEMA'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 will be toast." [17]

Recent findings conclude that the Cascadia subduction zone is more complex and volatile than previously believed. [18] 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. [19] [20] Geologists have also determined the Pacific Northwest is not prepared for such a colossal quake. The tsunami produced could reach heights of 80 to 100 feet (24 to 30 m). [21]

A 2004 study revealed the potential for relative mean sea level rise (caused by subsidence) along the Cascadia subduction zone. It postulated that cities on the west coast of Vancouver Island, such as Tofino and Ucluelet, are at risk for a 1–2 m subsidence, relative to mean sea level. [22]

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. [10] The Huu-ay-aht people have rebuilt their administration building on a high point of land in their territory; [10] 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. [23] The Quileute 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. [13] 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.[ citation needed ] The rate of convergence between the Juan de Fuca Plate and the North American Plate is 60 millimeters (2.4 in) per year. [24]

Bridge of the Gods – Bonneville Slide

It was once conjectured that the Cascadia earthquake may also have been linked to the Bridge of the Gods – Bonneville Slide and the Tseax Cone eruption in British Columbia, Canada. [25] However, recent investigations using radiocarbon dating and dendrochronology date the Bonneville landslide around 1450. [26] [27] [28]

See also

Related Research Articles

"Thunderbird and Whale" is an indigenous myth belonging to the mythological traditions of a number of tribes from the Pacific Northwest.

Cascadia and Cascadian are terms that derive from the Cascade Range and may refer to:

<span class="mw-page-title-main">1964 Alaska earthquake</span> Second most powerful earthquake in recorded history

The 1964 Alaskan earthquake, also known as the Great Alaskan earthquake and Good Friday earthquake, occurred at 5:36 PM AKST on Good Friday, March 27. Across south-central Alaska, ground fissures, collapsing structures, and tsunamis resulting from the earthquake caused about 131 deaths.

<span class="mw-page-title-main">Juan de Fuca Plate</span> Tectonic plate in the eastern North Pacific

The Juan de Fuca Plate is a small tectonic plate (microplate) generated from the Juan de Fuca Ridge that is subducting beneath the northerly portion of the western side of the North American Plate at the Cascadia subduction zone. It is named after the explorer of the same name. One of the smallest of Earth's tectonic plates, the Juan de Fuca Plate is a remnant part of the once-vast Farallon Plate, which is now largely subducted underneath the North American Plate.

<span class="mw-page-title-main">Cascadia subduction zone</span> Convergent plate boundary that stretches from northern Vancouver Island to Northern California

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 Gorda plates move to the east and slide below the much larger mostly continental North American Plate. The zone varies in width and lies offshore beginning near Cape Mendocino, Northern California, passing through Oregon and Washington, and terminating at about Vancouver Island in British Columbia.

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 earthquakes are the planet's most powerful, with moment magnitudes (Mw) that can exceed 9.0. Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes.

<span class="mw-page-title-main">Paleoseismology</span> Study of earthquakes that happened in the past

Paleoseismology looks at geologic sediments and rocks, for signs of ancient earthquakes. It is used to supplement seismic monitoring, for the calculation of seismic hazard. Paleoseismology is usually restricted to geologic regimes that have undergone continuous sediment creation for the last few thousand years, such as swamps, lakes, river beds and shorelines.

<span class="mw-page-title-main">Cape Mendocino</span> Cape in Mendocino County, California, United States

Cape Mendocino, which is located approximately 200 miles (320 km) north of San Francisco, is located on the Lost Coast entirely within Humboldt County, California, United States. At 124° 24' 34" W longitude, it is the westernmost point on the coast of California. The South Cape Mendocino State Marine Reserve and Sugarloaf Island are immediately offshore, although closed to public access due to their protected status. Sugarloaf Island is cited as California's westernmost island.

<span class="mw-page-title-main">Seismicity of the Sanriku coast</span>

The seismicity of the Sanriku coast identifies and describes the seismic activity of an area of Japan. Seismicity refers to the frequency, type and size of earthquakes experienced over a period of time. The Sanriku coast is a descriptive term referring to the coastal areas of the former provinces of Rikuō in Aomori, Rikuchū in Aomori, and Rikuzen in Miyagi.

<span class="mw-page-title-main">Huu-ay-aht First Nations</span> First Nations band government in British Columbia, Canada

The Huu-ay-aht First Nations is a First Nations band government based on Pachena Bay about 300 km (190 mi) northwest of Victoria, British Columbia on the west coast of Vancouver Island, in Canada. The traditional territories of the Huu-ay-aht make up the watershed of the Sarita River. The Huu-ay-aht is a member of the Nuu-chah-nulth Tribal Council and is a member of the Maa-nulth Treaty Society. It completed and ratified its community constitution and ratified the Maa-nulth Treaty on 28 July 2007. The Legislative Assembly of British Columbia passed the Maa-nulth First Nations Final Agreement Act on Wednesday, 21 November 2007 and celebrated with the member-nations of the Maa-nulth Treaty Society that evening.

The 1946 Vancouver Island earthquake struck Vancouver Island on the coast of British Columbia, Canada, on June 23 at 10:15 a.m. with a magnitude estimated at 7.0 Ms and 7.5 Mw. The main shock epicenter occurred in the Forbidden Plateau area northwest of Courtenay. While most of the large earthquakes in the Vancouver area occur at tectonic plate boundaries, the 1946 Vancouver Island earthquake was a crustal event. Shaking was felt from Portland, Oregon, to Prince Rupert, British Columbia. 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.

<span class="mw-page-title-main">Teletsunami</span>

A teletsunami is a tsunami that originates from a distant source, defined as more than 1,000 km (620 mi) away or three hours' travel from the area of interest, sometimes travelling across an ocean. All teletsunamis have been generated by major earthquakes such as the 1755 Lisbon earthquake, 1960 Valdivia earthquake, 1964 Alaska earthquake, 2004 Indian Ocean earthquake, and 2021 South Sandwich Islands earthquakes.

The 1992 Cape Mendocino earthquakes occurred along the Lost Coast of Northern California on April 25 and 26. The three largest events were the M7.2 thrust mainshock that struck near the unincorporated community of Petrolia midday on April 25 and two primary strike-slip aftershocks measuring 6.5 and 6.6 that followed early the next morning. The sequence encompassed both interplate and intraplate activity that was associated with the Mendocino Triple Junction, a complex system of three major faults that converge near Cape Mendocino. The total number of aftershocks that followed the events exceeded 2,000.

Kenji Satake is a Japanese seismologist who has made significant contributions to subduction and tsunami research. Along with Brian Atwater and David Yamaguchi, Satake assembled disparate pieces of information regarding a Japanese tsunami that had no known origin. The three scientists worked together to pinpoint a date, time, and location for the 1700 Cascadia earthquake – 9 p.m. on January 26, 1700 – on the Cascadia Subduction Zone off the Pacific Northwest coast of North America.

<span class="mw-page-title-main">Ghost forest</span> Areas of dead trees in former forests

Ghost forests are areas of dead trees in former forests, typically in coastal regions where rising sea levels or tectonic shifts have altered the height of a land mass. Forests located near the coast or estuaries may also be at risk of dying through saltwater poisoning, if invading seawater reduces the amount of freshwater that deciduous trees receive for sustenance.

Pachena Bay is located 13 km (8.1 mi) south of Bamfield in Pacific Rim National Park at the southern end of Vancouver Island, British Columbia, Canada. It was the location of a First Nation's village that was destroyed by a tsunami in 1700.

The Nemuro-Oki earthquake in scientific literature, occurred on June 17 at 12:55 local time. It struck with an epicenter just off the Nemuro Peninsula in northern Hokkaidō, Japan. It measured 7.8–7.9 on the moment magnitude scale (Mw ), 8.1 on the tsunami magnitude scale (Mt ) and 7.4 on the Japan Meteorological Agency magnitude scale (MJMA ).

<span class="mw-page-title-main">1585 Aleutian Islands earthquake</span> 16th-century seismic event in the North Pacific Ocean

The 1585 Aleutian Islands earthquake is the presumed source of a tsunami along the Sanriku coast of Japan on June 11, 1585, known only from vague historical accounts and oral traditions. The event was initially misdated to 1586, which led to it being associated with the deadly earthquakes in Peru and Japan of that year. The source earthquake was later determined by modern seismological studies to have originated near the Aleutian Islands in the North Pacific Ocean. Paleotsunami evidence from shoreline deposits and coral rocks in Hawaii suggest that the 1585 event was a large megathrust earthquake occurring on the Aleutian subduction zone with a moment magnitude (Mw ) as large as 9.25.

<span class="mw-page-title-main">2021 Chignik earthquake</span> 7th largest earthquake in the US

An earthquake occurred off the coast of the Alaska Peninsula on July 28, 2021, at 10:15 p.m. local time. The large megathrust earthquake had a moment magnitude of 8.2 according to the United States Geological Survey (USGS). A tsunami warning was issued by the National Oceanic and Atmospheric Administration (NOAA) but later cancelled. The mainshock was followed by a number of aftershocks, including three that were of magnitude 5.9, 6.1 and 6.9 respectively.

The following is a timeline of the history of Oregon in the United States of America.

References

  1. 1 2 National Geophysical Data Center / World Data Service (NGDC/WDS) (1972), Significant Earthquake Database (Data Set), National Geophysical Data Center, NOAA, doi:10.7289/V5TD9V7K
  2. Atwater et al. 2005, p. 98
  3. Atwater, B. F.; Musumi-Rokkaku, S.; Satake, K.; Yoshinobu, T.; Kazue, U.; Yamaguchi, D. K. (2005). The Orphan Tsunami of 1700—Japanese Clues to a Parent Earthquake in North America . U.S. Geological Survey Professional Paper 1707. United States Geological SurveyUniversity of Washington Press. ISBN   978-0-295-98535-0.
  4. 1 2 Kenji Satake; Kunihiko Shimazaki; Yoshinobu Tsuji; Kazue Ueda (18 January 1996). "Time and size of a giant earthquake in Cascadia inferred from Japanese tsunami records of January 1700". Nature. 379 (6562): 246–249. Bibcode:1996Natur.379..246S. doi:10.1038/379246a0. S2CID   8305522.
  5. 1 2 3 4 Kathryn Schulz (July 20, 2015). "The Really Big One". The New Yorker .
  6. 1 2 "Jan. 26, 1700: How Scientists Know When The Last Big Earthquake Happened Here". Oregon Public Broadcasting, January 26, 2015.
  7. "Ghosts of Tsunamis Past" Archived 2018-08-28 at the Wayback Machine . American Museum of Natural History.
  8. 1 2 3 4 5 Ruth S. Ludwin; Robert Dennis; Deborah Carver; Alan D. McMillan; Robert Losey; John Clague; Chris Jonientz-Trisler; Janine Bowechop; Jacilee Wray; Karen James (2005), "Dating the 1700 Cascadia Earthquake: Great Coastal Earthquakes in Native Stories" (PDF), Seismological Research Letters, 76 (2): 140–148, doi:10.1785/gssrl.76.2.140, archived from the original (PDF) on 2015-07-24, retrieved 2015-07-24
  9. "Tsunamis and Earthquakes – Native American Legends of Tsunamis in Pacific NW – USGS PCMSC".
  10. 1 2 3 Meissner, Dirk (18 January 2015), "Earth will rip open like a zipper, expert says, when overdue Vancouver Island quake strikes", Toronto Star , retrieved 19 January 2015
  11. "Prepare for next tsunami, says chief". Raven's Eye, Vol. 8, No. 9, 2009.
  12. "Cascadia’s Locked Fault Means Massive Earthquake Is Due in Pacific Northwest: Seismologists" Archived 2015-07-31 at the Wayback Machine . Indian Country Today Media Network , December 16, 2014.
  13. 1 2 "Haida Gwaii Quake Brings Home the Importance of Quileute Relocation Legislation" Archived 2016-08-23 at the Wayback Machine . Indian Country Today Media Network , November 6, 2012.
  14. "Get ready for the Big One". The Globe and Mail , April 22, 2011.
  15. Witter, Robert C.; Kelsey, Harvey M.; Hemphill-Haley, Eileen (October 2003). "Great Cascadia earthquakes and tsunamis of the past 6700 years, Coquille River estuary, southern coastal Oregon". Geological Society of America Bulletin. 115 (10): 1289–1306. Bibcode:2003GSAB..115.1289W. doi:10.1130/b25189.1.
  16. Yanev, Peter (27 March 2010). "Shake, Rattle, Seattle". The New York Times. p. WK11.
  17. Schulz, Kathryn (20 July 2015). "The Really Big One". The New Yorker.
  18. "A Major Earthquake in the Pacific Northwest Looks Even Likelier". The Atlantic. August 16, 2016.
  19. "Odds Are 1-In-3 That A Huge Quake Will Hit Northwest In Next 50 Years". Oregon State University. 24 May 2010. Archived from the original on 27 May 2010. Retrieved 2010-05-24.
  20. Oregon State University (May 25, 2010). "Odds are about 1-in-3 that mega-earthquake will hit Pacific Northwest in next 50 years, scientists say". ScienceDaily (Press release).
  21. "Perilous Situation". The Oregonian. 2009-04-19. Archived from the original on 23 April 2009. Retrieved 2009-05-12.
  22. Leonard, Lucinda J.; Hyndman, Roy D.; Mazzotti, Stéphane (2004). "Coseismic subsidence in the 1700 great Cascadia earthquake: Coastal estimates versus elastic dislocation models". GSA Bulletin . 116 (5–6): 655–670. Bibcode:2004GSAB..116..655L. doi:10.1130/B25369.1.
  23. Munro, Margaret (March 8, 2012). "Monster earthquake threat looms over B.C. coastal communities". Vancouver Sun . Archived from the original on February 3, 2019. Retrieved January 27, 2019.
  24. Kate Potter (September 2007). "The Big One: Understanding Why The Big Earthquake Is Predicted For Vancouver". The Science Creative Quarterly. Archived from the original on 27 May 2009. Retrieved 2009-05-18.
  25. Hill, Richard L. (2002-05-15). "Great Cascadia Earthquake Penrose Conference". The Oregonian. Archived from the original on 2008-10-24.
  26. O'Connor, Jim E. (September 2004). "The Evolving Landscape of the Columbia River Gorge: Lewis and Clark and Cataclysms on the Columbia". Oregon Historical Quarterly. 105 (3): 390–421. doi:10.1353/ohq.2004.0043. S2CID   131976728. Archived from the original on 2009-03-28. Retrieved 2009-09-07.
  27. Pringle, Patrick T. (2009). "The Bonneville slide" (PDF). Columbia Gorge Interpretive Center Museum Explorations (Fall-Winter 2009): 2–3. Archived from the original (PDF) on 2018-01-05. Retrieved 2012-02-03.
  28. "10,000 years of Cascadia earthquakes". The Oregonian . Retrieved June 11, 2019.

General

Native and Japanese accounts

Current hazards