While many of the volcanoes within the United States are well known, their counterparts
in Canada are not.
And this is despite the fact that Canada has been the site of more than three dozen volcanic
eruptions in the last 10,000 years, the last of which occurred in 1904, as a lava flow
from the little known Iskut Unuk river cones volcano flowed a total of 20 kilometers, eventually
going across the international border and into Alaska.
Another volcano which is closer to a population center, the well preserved Kostal Cone erupted
around 1600, while a deadly volcanic eruption occurred from the Tseax cone around 1700,
resulting in the deaths of several thousand idigenious peoples.
In total, Canada has 19 volcanoes which could probably be classified as active, having produced
an eruption at some point since the end of the last ice age, in addition to a 20th volcano
which might appear extinct but still produces active mud volcanoes, a 21st volcano with
recent seismicity and a 22nd volcano with no known Holocene eruptions but with a number
of vents presumably under 50,000 years old.
Thus, in the style of the U.S. Geological Survey's National Volcanic Threat Assessment
linked in this video's description, I have created the equivalent for the 22 volcanic
complexes in Canada.
Used to calculate this threat rating score are a series of factors for each volcano which
include things such as (by the way this list is not all inclusive, there are more factors
than what I am about to mention) the frequency and size of volcanic eruptions, whether eruptions
are dominantly effusive or explosive, amount of nearby infrastructure, amount of nearby
air traffic, and the amount of nearby population.
And, I want to note that volcanoes anywhere on this scale can be potentially dangerous
or deadly given a certain set of circumstances, such as a volcanic eruption.
Before I reveal the full list, I would like to thank the sponsor of this extended duration
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Now, as promised, here is the Canadian Volcano Hazard Assessment list in full with a similar
threat score volcano within the United States shown on the right side for comparison.
I want to note that I am not affiliated with the United States or Canadian governments
or their Geological Surveys, this is simply my personal opinion based interpretation of
various volcanoes in Canada using a specific U.S. Geological Survey methodology.
I will now briefly explain each of these volcanic complexes.
Starting from the bottom of this list are two volcanoes which are highly remote in British
Columbia, not located near any major airports, and only have a minimal population within
30 kilometers of them.
Both coming in with a threat score of 0 are the Dark Mountain Volcanic Field and Castle
Rock.
Both complexes are composed of subglacial vents known as tuyas and subglacial mounds
which have a generally dark coloration.
However, it is quite likely that the Dark Mountain complex has not erupted in more than
20,000 years, and the same is probably true of Castle Rock except it has produced occasional
seismic activity, suggesting it might have some form of deep magma reservoir.
The last very low threat volcano is the Tuya Volcanic Field which last erupted around 10,000
years ago producing the Gabrielse Cone and a medium length lava flow.
The only nearby city to this complex is Jade City which as the name implies is the site
of jade mining.
Moving into the low threat category we have the Alligator Lake complex 40 kilometers southwest
of the city of Whitehorse in Yukon which consists of two post glacial cinder cones.
On the southwest section of Swindle Island is the most recent volcanic vent of the Milbanke
Sound complex, a volcanic field that covers an area of 500 square kilometers across several
islands in western British Columbia.
The Bridge River cones probably last erupted at some point in the last 5,000 years but
not much is known about them.
The second most active volcano in Canada which last erupted in 1904 is the Iskut-Unuk River
Cones, which has erupted approximately a dozen times since the end of the last ice age.
Luckily, only a single dam is located near this remote volcano.
The highest threat Yukon volcano is the Fort Selkirk Volcanic Field which produced a single
volcanic eruption north of the city of Fort Selkirk approximately 7.5 thousand years ago.
The Hoodoo Mountain tuya which is still glacier covered comes in next on the list, while three
volcanic cones east and northeast of the city of Alin come in next.
The Tseax cone which has erupted twice in the last 1,000 years and produced a deadly
eruption which killed thousands in the 18th century comes in only in the upper end of
the low threat category because in comparison to many volcanoes higher on this list, it
is not as explosive.
The remote Level Mountain volcano may have erupted around 12,000 years ago, possibly
producing the Finlay tephras, and today still has active mud volcanoes present suggesting
a possible at depth magmatic source.
This might seem a bit surprising to call this volcano potentially active due to its substantial
level of erosion, but some evidence does point this way.
The mantle hotspot caused Nazko volcano produced its most recent of three eruptions 7,000 years
ago, and is not close to any major cities but is close to some logging operations.
This volcano was near the site of a possible very deep magmatic intrusion which did not
travel very far into the crust during 2007 and today has several volcanic gas seeps which
release carbon dioxide gas.
The first purely explosive volcano on this list is the remote Crow Lagoon complex which
consists of at least two explosion craters termed maars which are each up to a kilometer
across and 200 meters deep.
In the lower end of the moderate threat category is the Wells Gray-Clearwater Volcanic Field.
It has erupted 4 times in the last 10,000 years including an eruption in 1600 which
were generally moderately explosive, but has also produced explosive maars, and has been
the site of recent earthquakes.
The Spectrum Range volcano contains an abundance of beautiful hydrothermally altered rock and
has been the site of moderately explosive basaltic and highly explosive rhyolitic eruptions.
It has erupted twice in the last 10,000 years, and the reason it is ranked so highly despite
no major nearly population centers is its proximity to the Juneau International Airport.
Next on this list, the Silverthrone Caldera at one point probably between 200,000 and
2 million years ago produced a powerful VEI 7 explosive eruption which was more than 100
times more voluminous than the 1980 eruption of Mount Saint Helens.
This eruption formed a 30 kilometer long and 19 kilometer wide caldera which is now covered
by many glaciers.
Silverthrone has only produced 1 eruption which was a small probably VEI 2 cinder cone
forming eruption in the last 10,000 years.
The most active volcano on this list with possibly as many as 30 eruptions in the last
11,650 years and the first high threat volcano is Mount Edziza.
It has a large 2.8 kilometer wide caldera, has produced numerous recent cinder cones
such as the Eve Cone, many additional lava flows, and as a stratovolcano has produced
many explosive eruptions.
Yet, it is not higher up on this list due to the lack of any significant population
centers nearby.
Although the Mount Cayley stratovolcano has probably only erupted once since the end of
the last ice age, the fact that its eruptions are almost always highly explosive, and that
many of its flanks travel into valleys which lead to several towns make this a high threat
volcano.
Next, we have the high threat Garibaldi Lake volcanic field and the very high threat Mount
Garibaldi volcano.
Altogether, they have produced 4 volcanic eruptions in the last 15,000 years, 1 of which
formed a tuya, and the other 3 of which were highly explosive, resulting in unusually long
dacite lava flows which if they were to happen again could cause a high degree of destruction
to the more than 10,000 people who live in the region.
The highest threat volcano in Canada is Mount Meager, which could sort of be thought of
as Canada's Mount Saint Helens.
Approximately 2400 years ago it produced a Mount Saint Helens like highly explosive plinian
volcanic eruption on the same order of magnitude as the 1980 eruption of Mount Saint Helens,
registering in as a VEI 5 and ejecting 1 cubic kilometer of tephra.
It deposited in some locations more than a half meter thick of ash, created voluminous
pyroclastic flows, while also creating long reaching destructive lahars.
Today, Meager has numerous hot springs and active fumaroles that proves it still has
an at depth magma chamber while also producing more recent earthquake swarms than any other
volcano on this list in Canada.
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