History Podcasts

Cascadia: The Other “Lost Continent” – Part I

Cascadia: The Other “Lost Continent” – Part I

It was said that the end came without warning...

Once, long ago, as the people slept, the sun came out at night. It shot a flaming arrow across the heavens which burst into thousands of fragments, which then fell to the earth. The people were startled out of their sleep by a rumbling and quaking of the earth. The skies above them were on fire. The waters of the lakes and oceans rose. Soon the waves became mountains of water that rose against the shores. The sun was blotted out and darkness covered the great green land and water. Terrified, the people ran to the hills to get away from the pounding water. For days the earth rumbled and quaked. Torrents of rain began coming down so fiercely that water sprouted up out of the ground everywhere, overflowing the creeks and rivers. The people who knew where there was a cave high up on the mountain fled to it and saved themselves; all of those who stayed behind were drowned. It rained for a long, long time until all the valleys and low-lands became one churning sea. Only the tops of the highest mountains remained uncovered, where the people stood huddled together listening to the wails below as countless bodies were tossed upon the angry waves, and then sank to their graves in the unknown depths.

Then a rain of ashes began to fall…

Deluge. Late 19 th century painting by Leon Comerre.

Legends of Lost Lands

Most people have heard about the fabled lost continents of Atlantis and Lemuria.

From the earlier century, alternative-history writers have been busy following a puzzling trail of historical and archeological curiosities which suggest the existence of a high civilization that was wiped out by some kind of prehistoric cataclysm, and virtually erased from human memory.

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The opening passage sounds like one of the countless descriptions chronicling the fall of Atlantis or Lemuria in a deluge; but this is, in fact, a description of a cataclysm which devastated the Pacific Northwest during prehistoric times, and was recorded in the lore and oral traditions of northwestern Native Americans.

Exploring the edges of a lost and forgotten land is an exciting dream and journey.

For as long as I can remember I’ve been fascinated by the visionary concepts of the “lost civilizations” of Atlantis and Lemuria. But my own interrogations into the mysteries of the past did not lead me to wander as far afield as other researchers have strayed.

When I began researching historical mysteries and lost continents over a decade ago, I didn’t have the faintest idea that I was living amidst one of the oldest, most mysterious, and most stunningly scenic places on the face of the planet.

(Copyright © Dustin Naef). Mount Shasta's Forgotten History & Legends, 2016.“Yachats, Oregon. At one time approximately 12,000 years ago much of the land along the Pacific Coast extended miles further out to sea than it does today. These areas sank beneath the waters of the ocean as rising sea levels were caused by catastrophic mega-floods.”

Looking back, I realize now that I no longer have to dream of exploring fabled lost lands somewhere far away across the world’s oceans. North America has its own lost and forgotten continent, whose mysterious legends, history and great monuments stand out in their own right; this is a land which belongs uniquely to itself–it’s not necessary to evoke visions of Atlantis or Lemuria in order to define its grandeur or reality, or make it into something it never was.

(Image credit copyright © Dustin Naef). “The spectacular scenery and geology of Washington State's Columbia Gorge was created by cataclysmic flooding which scoured the region over its destructive path towards the Pacific Ocean, creating dramatic landscapes found nowhere else on Earth.”

Tipsoo Lake, Mt. Rainier Nat'l Park, Washington. (Image credit copyright Loree Johnson. http://loree-johnson.pixels.com/featured/first-light-on-mount-rainier-loree-johnson.html)

Cascadia: A vast, dark green land of mystery

Here in the western hemisphere there exists a vast, dark green mountainous wilderness of deep mystery and astonishing beauty, which stretches along the Pacific Coast for more than a thousand miles.

Although the land has been arbitrarily carved up into six states, those who have lived in this region since time immemorial know that it is really one great, green land.

(Image credit copyright © Dustin Naef). Mount Shasta's Forgotten History & Legends, 2016.“Palouse Falls, Washington. Evidence of a prehistoric deluge can be seen throughout the Cascadia region. The region's plunging waterfalls, flood-carved landscapes, and steep-walled canyons were created by glacial mega-floods.”

The “Pacific Northwest” is a label coined to describe a piece of real estate rather than a real place, it was imposed on this land by the U.S. Congress and railroad companies, during an ad-campaign to promote the region as an attractive place to industrialize and live.

  • The Ancient Civilizations that Came Before: Self-Eradication, Or Natural Cataclysm? – Part I
  • The Carolina Bays and the Destruction of North America
  • The Rise and Fall of Cahokia: Did Megafloods Spell the End of the Ancient Metropolis?

In an effort to dissolve imaginary national boundaries, writers and activists began referring to the Pacific Northwest as “Cascadia” as far back the early ‘80s.

Map of Cascadia. (Image credit David McClosky. Map details can be found at: http://www.marshamccloskey.com/cascadiamap.html)

At that time few people besides geologists had ever heard of the term.

But today a growing number of people are learning and speaking about the Cascadia region, calling it the “Land of Falling Waters”. Some people are even beginning to call themselves ‘Cascadians’.

(Image credit copyright © Dustin Naef) [inset image public domain National Park Service]. Mount Shasta's Forgotten History & Legends, 2016. “Dry Falls Lake, Washington. At five times the width of Niagra Falls, Dry Falls is believed to be the greatest known waterfall on the face of the planet. It was created by catastrophic flooding around the end of the last Ice Age. It is estimated that the amount of water once flowing over Dry Falls amounted to ten times the current volume of all the rivers in the world combined.”

Every land has a story to tell. And the ancient history and legends of Cascadia are as captivating as those of any other place in the world— real or imagined.

As the plunge of tumbling and falling waters collectively make up the voice of Cascadia’s wilderness, the element of water is where some of the earliest prehistoric legends of Cascadia begin.

(Image credit © Dustin Naef). “It is believed that around 12,800 years ago a giant comet entered our solar system and broke up into many large fragments, which fell the Earth liquefying masses of ice, and causing glacial mega-floods and other natural disasters.”

[Read Part 2: Cascadia: A Vast, Dark Green Land of Mystery ]

Dustin Naef is author of “ Mount Shasta's Forgotten History & Legends ” Available on Amazon and other major online Booksellers September 30, 2016. See more at: www.mountshastasmysteries.com


Cascadia subduction zone

Coordinates: 45°N 124°W  /  45°N 124°W  / 45 -124 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. [1]

The Explorer, Juan de Fuca, and Gorda plates are some of the remnants of the vast ancient Farallon Plate which is now mostly subducted under the North American Plate. The North American Plate itself is moving slowly in a generally southwest direction, sliding over the smaller plates as well as the huge oceanic Pacific Plate (which is moving in a northwest direction) in other locations such as the San Andreas Fault in central and southern California.

Tectonic processes active in the Cascadia subduction zone region include accretion, subduction, deep earthquakes, and active volcanism of the Cascades. This volcanism has included such notable eruptions as Mount Mazama (Crater Lake) about 7,500 years ago, the Mount Meager massif (Bridge River Vent) about 2,350 years ago, and Mount St. Helens in 1980. [2] Major cities affected by a disturbance in this subduction zone include Vancouver and Victoria, British Columbia Seattle, Washington and Portland, Oregon.

One or many?

The 1700 quake occurred where the Juan de Fuca tectonic plate is subducting, or pushing under, the North American plate. The traditional view is that about 620 miles (1,000 kilometers) of fault line between Vancouver Island and northern California broke in the quake. The earthquake caused the coastline to drop in elevation, a process called subsidence.

Geologists can detect this subsidence by studying microscopic organisms called diatoms that live in the marshes along the Cascadia coastline. These diatoms are very sensitive to sea level, so which species were present in sediments from a particular place can reveal how deep the ocean water was at that time. Researchers can also trace the path of the 1700 tsunami in rock, sand and soil deposits laid down by the mass of water.

Melgar’s main line of research focuses on tsunami warning systems. Part of that research involves creating databases of simulated earthquakes and their associated tsunamis. With this database at his disposal, he decided to see if he could compare the simulations with the geological evidence left behind after 1700. He wanted to know, he said, if there were any earthquake scenarios he could rule out.

He found that the traditional view of a magnitude-9 or so quake hitting on Jan. 26, 1700, and breaking hundreds of miles of fault in one fell swoop is indeed possible. But the geological evidence is also consistent with a quake that was slightly less powerful and that broke only about half of the length previously predicted.

The rest of the coastline subsidence would have then occurred in a series of several other large quakes over the course of a decade. Instead of a single magnitude-9 quake, Melgar said, perhaps the Jan. 26 temblor was an 8.7, followed a few years later by an 8.4, then an 8.3 or an 8.2 the year after that. As long as the subsequent quakes were less than a magnitude 8.6, they would not have led to another tsunami in Japan.

Board of Directors

The board of directors provides leadership for the foundation which is a non-profit 501(c)3 organization aligned with Cascadia College. Directors support the college and its students by building relationships and developing resources in the community. Directors are elected by their peers to serve up to three consecutive three-year terms.

Alex Lee, President
Auxano Advisors

Ron Wheadon, Vice President
Cascadia College - retired

Alex Lee, Treasurer
Auxano Advisors

Vacant, Secretary

Ales deGolia
Management Recruiters of Coeur d'Alene, Vice President

Kelly Snyder
Snohomish County, Public Works Director

Grete Schultz
Solid Ground, Managing Attorney

Dr. Eric Murray
President, Cascadia College

Mark Collins
Director, Cascadia College Foundation

The Cascadia Conservation District is a non-regulatory organization, funded by grants and a system of rates & charges, dedicated to encouraging the wise stewardship of all natural resources in Chelan County.

Our board and staff members work cooperatively with local landowners and communities to provide technical and financial assistance for soil, water, forest, fish, and wildlife conservation efforts. We currently serve all of Chelan County.

Explore our website to learn more about what programs we are involved in and how we are working with local landowners, agencies, non-profits and other stakeholders to develop and implement conservation projects in Chelan County that benefit both people and the environment.

Due to the increasing risk of exposure to the novel coronavirus and the associated respiratory illness COVID-19 in Washington State, Cascadia Conservation District is taking the following steps to reduce exposure to the virus until Governor Inslee's "Stay Home, Stay Healthy" order is lifted .

Staff are working remotely to reduce their exposure. Phone or email will be the best way to reach them.

Cascadia will not hold public gatherings until guidance from the State of Washington changes.

Questions may be directed to Ryan Williams, Executive Director at [email protected]


Numbering nearly 3000 strong, Conservation Districts are found in almost every county across the United States. We are non-regulatory entities established to provide landowners with technical and financial assistance with natural resource projects.

The Cascadia Conservation District produces the seasonal Conservation Quarterly newsletter that highlights current projects, upcoming events and conservation issues relevant to our region.

"Water is the most critical resource issue of our lifetime and our children's lifetime. The health of our waters is the principal measure of how we live on the land."
- Luna Leopold

Your unique experience and talents can be put to good use through volunteer opportunities, while providing you with the opportunity to give back to your local community and do your part for the environment.

Transfer Credits to your Degree or Certificate at Cascadia

Credits earned at colleges or universities that are recognized by a regional accreditation association or Ministry of Education are accepted for evaluation. No more than 5 credits of "D" level work will be accepted. Official transcripts are reviewed and credits transferred after you have registered for classes for your first quarter. Evaluations are completed in the order in which official transcripts and the Evaluation Request form are received.

Complete the Transcript Evaluation Request Form and send official transcripts from all previous colleges and universities to Cascadia College. Official transcripts may be submitted electronically directly from your previous institution (Washington state public colleges or universities only) or mail official transcripts to:

If you have earned a four-year degree, you are not required to submit official transcripts unless credits will be used towards a degree or certificate at Cascadia. Unofficial transcripts may be required to provide evidence of placement level before registering for English or math courses or for courses with a prerequisite of English or math.

Reciprocity Agreement

Washington community and technical colleges (CTC) offer a reciprocity agreement to students transferring within the CTC system who are pursuing one of the Direct Transfer Agreement (DTA) degrees. Individual courses that met distribution requirements or fulfilled entire areas of degree requirements at one college will be considered to have met those same requirements if you plan to complete the same degree after transferring to another community or technical college in Washington. You must initiate the review process and be prepared to provide necessary documentation. For complete information and forms, please contact the Assistant Director for Enrollment Services at (425) 352-8125.

Advanced Placement (AP) Credit

When registering for AP tests, request that the College Board send official sealed AP test scores directly to Enrollment Services. You must also fill out a Transcript Evaluation Request Form and turn it in to the front counter in Kodiak Corner in order for the scores to be evaluated and credits transferred to Cascadia. See the Academic Policies for Credits and Placement.

Cascadia College will award unrestricted elective credit for an Advanced Placement score of 3 or higher. Credit will be awarded on the basis of official AP results, not transcript notation. Credits granted for general education or major requirements are listed below. Credit for exams not listed below with a score of 3 or higher will be awarded credit within the distribution area of the subject matter.

See below for specific course equivalencies. A maximum of 30 alternative credits (AP and IB) may be used toward any degree.

AP Score


MATH& 151 and 152
(10 credits)

CHEM& 121 (5 credits) or
CHEM&161 and &162
(10 credits)

CHEM& 121 or
CHEM& 161 (5 credits)

English Language & Composition

English Literature & Composition

FRCH& 121, FRCH& 122,
FRCH& 123 (15 credits)

FRCH& 121, FRCH& 122
(10 credits)

Government and Politics: US

Government and Politics: Comparative

Humanities or
Social Science (HIST XXX 5 credits)

HIST& 146 and HIST& 147
or 148 (10 credits)

HIST& 146 or HIST& 147
(5 credits)

HIST& 126 and HIST&
127 or 128 (10 credits)

HIST& 126 or HIST& 127
(5 credits)

JAPN& 121, JAPN& 122.
JAPN& 123 (15 credits)

JAPN& 121, JAPN& 122
(10 credits)

Science Distribution (5 credits)

Science Distribution (5 credits)

Science Distribution (5 credits)

Science Distribution (5 credits)

Physics C: Electricity and Magnetism

Science Distribution (5 credits)

SPAN& 121, SPAN& 122,
SPAN& 123 (15 credits)

SPAN& 121, SPAN& 122
(10 credits)

Cambridge International Examination

The chart included on this page represents course equivalencies awarded for each Cambridge International (CI) exam score and recognized by all community and technical colleges in Washington. Colleges may award additional credits based on local policies, when appropriate, but should not award course equivalency credit for scores lower than those listed in this table. Students interested in transferring to a four-year university should check the requirements of their target school to determine the best way to use their IB exam credits.

Washington state community and technical colleges will award unrestricted elective credit for a Cambridge (CI) score of E on A and AS level exams. Credit will be awarded on the basis of official CI results, not transcript notation. Credits granted for general education or major requirements will be specified by the receiving institution’s CI credit policies otherwise, elective credit will be granted.

Requirements of the Associate of Arts (AA) General Transfer degree allow ten (10) credits maximum from any single department for Humanities Social Sciences and Natural Sciences distribution requirements. A maximum of five (5) credits of World Language can be used for Humanities distribution .

Name Exam Minimum Credit
Accounting A Level ACCT&201, ACCT&202, and ACCT&203 (15)
Accounting AS Level Humanities distribution in art (10) and general electives (5)
Art & Design A Level Humanities distribution in art (10) and general electives (5)
Art & Design AS Level Humanities distribution in art (7.5)
Biology A Level Natural science distribution in biology, with lab (10) and general electives (5)
Biology AS Level Natural science distribution in biology, with lab (7.5)
Business A Level BUS 900 (5) and business electives (10)
Business AS Level BUS 900 (5) and business electives (2.5)
Chemistry A Level CHEM&161, CHEM&162, and CHEM&163 (15)
Chemistry AS Level Natural science distribution in chemistry, with lab (7.5)
Chinese A Level World language (10) and humanities distribution (5)
Chinese - Language AS Level World language (7.5)
Classical Studies A Level Humanities distribution (10) and general electives (5)
Classical Studies AS Level Humanities distribution (7.5)
Computer Science A Level Computer science for non-majors (5) and general electives (10)
Computer Science AS Level Computer science for non-majors (5) and general electives (2.5)
Digital Media & Design A Level Humanities distribution (10) and general electives (5)
Digital Media & Design AS Level Humanities distribution (7.5)
Drama A Level DRMA& 101 (5), humanities distribution (5), and general electives (5)
Drama AS Level DRMA& 101 (5) and humanities distribution (2.5)
Economics A Level ECON&201 (5), ECON&202 (5), and general electives (5)
Economics AS Level Social science distribution in economics (7.5)
English - Language A Level General electives (15)
English - Language AS Level General electives (7.5)
English - Language and Literature AS Level General electives (7.5)
English - Literature A Level Humanities distribution (10) and general electives (5)
English - Literature AS Level General electives (7.5)
English General Paper AS Level General electives (7.5)
Environmental Management AS Level Natural science distribution, with lab (7.5)
French A Level FRCH&121, FRCH&122, and FRCH&123 (15)
French - Language AS Level FRCH&123 (5) and humanities distribution (5)
Geography A Level Social science distribution (10) and general electives (5)
Geography AS Level Social science distribution (7.5)
German A Level World language (15)
German - Language AS Level World language (5) and humanities distribution (5)
Global Perspectives and Research A Level General electives (15)
Global Perspectives and Research AS Level General electives (7.5)
History A Level Humanities or social science distribution in history (10 in one or 5 in each) and general electives (5 to 10)
History AS Level Humanities or social science distribution in history (7.5)
Japanese - Language AS Level World language (5) and humanities distribution (2.5)
Marine Science A Level Natural science distribution, with lab (10) and general electives (5)
Marine Science AS Level Natural science distribution, with lab (7.5)
Mathematics A Level MATH&151 (5), MATH&152 (5), and mathematics electives (5)
Mathematics AS Level Mathematics electives (7.5)
Mathematics - Further A Level MATH&146 (5), MATH&153 (5), and mathematics electives (5)
Mathematics - Further AS Level Mathematics electives (7.5)
Media Studies A Level Humanities distribution in communication (10) and general electives (5)
Media Studies AS Level Humanities distribution in communication (7.5)
Music A Level Humanities distribution in music (10) and general electives (5)
Music AS Level Humanities distribution in music (7.5)
Physical Education A Level General electives (15)
Physical Education AS Level General electives (7.5)
Physics A Level PHYS&114, PHYS&115, and PHYS&116 (15)
Physics AS Level Natural science distribution in physics, with lab (7.5)
Psychology A Level PSYC&100 (5), social science distribution in psychology (5), and general electives (5)
Psychology AS Level Social science distribution in psychology (7.5)
Sociology A Level SOC&101 (5), social science distribution in sociology (5), and general electives (5)
Sociology AS Level Social science distribution in sociology (7.5)
Spanish A Level SPAN&121, 122, and 123 (15)
Spanish - Language AS Level General electives (7.5)
Spanish - Literature AS Level Humanities distribution (7.5)
Thinking Skills A Level Humanities or social science distribution in philosophy (10 in one or 5 in each) and general electives (5 to 10)
Thinking Skills AS Level Humanities or social science distribution in philosophy (7.5)

For Cambridge exams that are not listed here (Afrikaans, Arabic, Divinity, Hindi, Hinduism, Information Technology, Islamic Studies, Law, Portuguese, Tamil, Travel & Tourism, or Urdu), please contact your college's Office of Admissions or Enrollment Services.

High School Transcripts

Students are not required to submit high school transcripts but there are instances where they will be helpful:

  • If you completed Chemistry or Physics and plan on continuing taking courses in either of those fields.
  • To meet math prerequisites. (See Math Placement via High School Transcript for details.)
  • To meet English 101 prerequisite (See English Placement via High School Transcript for details.)

Information from high school transcripts are not used placement purposes and not to satisfy degree requirements. Students submitting high school transcripts should do so to the Kodiak Corner upon admission to the college.

International Baccalaureate (IB) Credit

You must submit your Official IB transcript to Enrollment Services to receive IB credit. Name Cascadia as a recipient when registering for IB exams or submit a transcript request to IB North America You must also request official evaluation of your IB transcript by filling out a Transcript Evaluation Request Form and turning it in to the front counter in Kodiak Corner.

Cascadia College will award credit within the distribution area of the subject matter for an for an International Baccalaureate (IB) Standard Level (SL) or Higher Level (HL) exam score of 4 or higher. Credit will be awarded on the basis of official IB results, not transcript notation.

See below for specific course equivalencies . A maximum of 30 alternative credits (AP and IB) may be used toward any degree.

The Story of Cascadia's "Really Big One" Has a Lot to Do with Colonial Hubris

There's a key part of Kathryn Schulz's terrifying New Yorker earthquake story that really left me shaking my head. I'm not talking about how the tsunami "will look like the whole ocean, elevated, overtaking land," or how "the odds of the big Cascadia earthquake happening in the next fifty years are roughly one in three." One of the most shocking things to read in Schulz's account of the Cascadia subduction zone (CSZ) was also how recently science had stumbled upon it.

As Schulz explains, the "discovery" of the CSZ's violent underpinnings just a few decades ago wasn't really a new discovery at all. Local tribes had been passing down accounts of earthquakes and tsunamis that rocked Cascadia for centuries. In that way, Schulz's story also shines a harsh spotlight on a major scientific blindspot: the aspect of the discipline that's consistently valued one type of knowledge (colonial) over another (indigenous).

In 2013, Seattle Times science reporter Sandi Doughton went into more detail on some of the indigenous accounts of Cascadia's historical earthquakes in her book, Full Rip 9.0. She recounted how Robert Dennis, leader of the Huu-ay-yaht First Nation on Vancouver Island, learned about the most recent CSZ quake from his great-grandfather, Chief Louis Nookmis, at the kitchen table. But despite the existing indigenous knowledge of earthquakes, scientists took a much longer time to figure out (and confirm) that Cascadia wasn't actually seismically stable. In 2007, two researchers—historian Coll Thrush and seismologist Ruth Ludwin—published an article in the American Indian Culture and Research Journal that explored what this kind of delayed rediscovery of earthquake history meant.

The researchers cited multiple indigenous accounts of earthquakes, like this one:

Cascadia’s seismicity profoundly shaped indigenous peoples’ understandings of their homelands, and oral traditions collected by European, Canadian, and American newcomers paint vivid pictures of the effects of the region’s earthquakes on the communities that made their homes there. An elder of the Cowichan people of the eastern coast of Vancouver Island, for example, told ethnographer Charles Hill-Tout that "in the days before the white man there was a great earthquake. It began about the middle of one night. threw down. houses and brought great masses of rock down from the mountains. One village was completely buried beneath a landslide.” Accounts from peoples of the outer coast, meanwhile, speak to the tsunamis generated by quakes on the CSZ.

The same 2007 article also looked at the discipline of geology itself, and how closely the study of land developed alongside colonial conquests:

Geology crystallized as a discipline in tandem with Europe’s domination of large swaths of the world. It was shaped by those encounters Alix Cooper has argued persuasively that European “discoveries” around the world led intellectuals, including mineralogists and other natural historians, to understand their own homelands in new ways, which in turn shaped how explorers, colonists, and others saw the “new” worlds. Geology was central to this process in that it offered a methodology to fuel the planet’s industrial and economic transformation, but it also transformed historical narratives about the earth and its peoples.

Colonial scientists and administrators typically ignored or dismissed indigenous peoples’ own forms of knowledge. Out of the Enlightenment’s certainties, new binaries were born: Europeans and their colonial offspring had art, science, and history, while the “natives,” whether in India, the Congo, or British Columbia, had corresponding (and, in the imperial mind, inferior) categories of craft, superstition, and myth. Geologists, paleontologists, and anthropologists often portrayed “races. whose existence had been hidden from mankind” to be “like the fossil bones of antediluvian animals,” which reinforced the perceived primitiveness of colonized landscapes and colonized peoples.

And just like the science of geology expanded with colonial conquest, indigenous ways of knowing were trivialized as Native people were killed, pushed out, disenfranchised, et cetera:

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Just as imperialism and the Enlightenment were linked more broadly, geological investigations of the Northwest Coast of North America went hand in hand with the dispossession of the region’s indigenous peoples and the denigration, dismissal, and dismantling of their systems of knowledge. From Meriwether Lewis’s descriptions of Northwest geomorphology to the painstakingly detailed soil descriptions of General Land Office surveys that facilitated homesteading, the systematic cataloging of Cascadia’s earthly wealth was a parallel process to—or perhaps more accurately, an integral component of—colonialism.

The good news is that science's narrow taste for certain types of data has begun to change. New indigenous-scientific collaborations are taking root, particularly here in the Pacific Northwest. Just look at the US Geological Survey's seven-year partnership with the Salish Canoe Journey, in which tribal canoes traveling hundreds of miles are able to take snapshots of ocean health every 10 seconds with attached water quality monitors. In 2008, the Swinomish Indian Tribal Community won funding from the US Department of Health and Human Services to launch a two-year study of climate impacts on tribal resources. Last year, the journal Ecology and Society even cited a timeless, living document from the Heiltsuk First Nation in its study of grizzly bear migration throughout British Columbia. And just this past spring, the Puyallup Tribe of Indians bought the Seattle Cancer Treatment and Wellness Center and opened the "first tribal-owned cancer care center in Indian Country and the United States," offering treatment to all.

"The brevity of our lives breeds a kind of temporal parochialism—an ignorance of or an indifference to those planetary gears which turn more slowly than our own," Schulz wrote in her piece. It's a frightening and sharply observed point. Her story also goes to show that cultural ignorance, too, will have made Cascadia all the more vulnerable when the Really Big One hits.

Unknown process

The geological processes that control when ETS occurs in Cascadia are still relatively unknown.

Southern Cascadia stands out as having more frequent events, but it is unclear why this is the case.

What sets southern Cascadia apart from the rest of the margin and allows it to have such short recurrence intervals between ETS events?

San Andreas Fault

One possible explanation may be its proximity to the northern San Andreas fault system. In northern California, the Cascadia subduction zone ends, and the plate boundary transitions into the San Andreas fault, a strike-slip system between the Pacific and North American plates.

Located less than 100 km apart, it may be possible that activity on the northern San Andreas fault is encouraging slow slip to occur in southern Cascadia and shortening the recurrence interval in this region.

Small stress changes on the northern San Andreas fault may be influencing the timing of ETS in southern Cascadia.

Was Cascadia's 1700 earthquake part of a sequence of earthquakes?

The famous 1700 Cascadia earthquake that altered the coastline of western North America and sent a tsunami across the Pacific Ocean to Japan may have been one of a sequence of earthquakes, according to new research presented at the Seismological Society of America (SSA)'s 2021 Annual Meeting.

Evidence from coastlines, tree rings and historical documents confirm that there was a massive earthquake in the U.S. Cascadia Subduction Zone on 26 January 1700. The prevailing hypothesis is that one megathrust earthquake, estimated at magnitude 8.7 to 9.2 and involving the entire tectonic plate boundary in the region, was responsible for the impacts recorded on both sides of the Pacific.

But after simulating more than 30,000 earthquake ruptures within that magnitude range using software that models the 3D tectonic geometry of the region, Diego Melgar, the Ann and Lew Williams Chair of Earth Sciences at the University of Oregon, concluded that those same impacts could have been produced by a series of earthquakes.

Melgar's analysis suggests that a partial rupture of as little as 40% of the megathrust boundary in one magnitude 8.7 or larger earthquake could explain some of the North American coastal subsidence and the 26 January 1700 Japan tsunami. But there could have also been as many as four more earthquakes, each magnitude 8 or smaller, that could have produced the rest of the subsidence without causing a tsunami large enough to be recorded in Japan.

His findings do not rule out the possibility that the 1700 Cascadia earthquake was a stand-alone event, but "the January 26, 1700 event, as part of a longer-lived sequence of earthquakes potentially spanning many decades, needs to be considered as a hypothesis that is at least equally likely," he said.

Knowing whether the 1700 earthquake is one in a sequence has implications for how earthquake hazard maps are created for the region. For instance, calculations for the U.S. Geological Survey hazard maps are based on the Cascadia fault zone fully rupturing about half the time and partially rupturing the other half of the time, Melgar noted.

"But are we really sure that that's real, or maybe it's time to revisit that issue?" said Melgar. "Whether there was a partial or full rupture fundamentally drives everything we put on the hazard maps, so we really need to work on that."

Since the first analyses of the 1700 earthquake, there have been more data from the field, repeated earthquake modeling of the Cascadia Subduction Zone and a better understanding of the physics of megathrust earthquakes -- all of which allowed Melgar to revisit the possibilities behind the 1700 earthquake. Researchers also have been writing code for years now to simulate earthquakes and tsunamis in the region, in part to inform earthquake early warning systems like ShakeAlert.

If there was a sequence of earthquakes instead of one earthquake, this might help explain why there is little good geologic evidence of the 1700 event in places such as the Olympic Mountains in Washington State and in southern Oregon, Melgar said.

He noted, however, that these specific areas are difficult to work in, "and may not necessarily be good recorders of the geological signals that paleoseismologists look for."

Melgar's models show that even a smaller Cascadia earthquake could cause a tsunami energetic enough to reach Japan. These smaller earthquakes could still pose a significant tsunami risk to North America as well, he cautioned. "They might be less catastrophic, because they don't affect such a wide area because the rupture is more compact, but we'd still be talking a mega-tsunami."

He suggested that it could be valuable to revisit and re-do old paleoseismological analyses of the 1700 event, to gain an even clearer picture of how it fits into the overall earthquake history of the region.

"Cascadia actually records earthquake geology much better than many other parts of the world," Melgar said, "so I think that just going back with modern methods would probably yield a lot of new results."

Earthquake hazard

That's not really good news for the Cascadia region, because multiple giant quakes would be no less hazardous than one enormous one. The geological history of the Cascadia subduction zones suggests that it experiences very large earthquakes every few centuries (between every 240 years and every 500 years). The question now is whether these temblors always occur as a single huge earthquake or if sometimes they're a series of very big ones.

"The tsunami might not be as large from an 8.1, but the shaking can be really intense," Melgar said. "It's just dangerous in a different way."

Indeed, a decade in which giant quakes hit every two or three years might even be more devastating to people living in the region than a single quake hitting every few hundred years. That's why it's important to get to the bottom of which scenario is more likely, Melgar told Live Science. This work would involve more detailed, high-tech modeling of tsunami waves from a magnitude-8 or magnitude-9 quake, as well as a closer look at the damage from 1700.

"We need to do a lot more fieldwork up and down Oregon, Washington, California and British Columbia," he said.

Watch the video: Tsunami Model Cascadia, Galactic News, 45k Yrs Ago. S0 News (January 2022).