Canada contains 21 active volcanoes.
One of these volcanoes recently displayed an increased amount of seismic activity within
British Columbia, indicating the movement of magma beneath the surface.
Additionally, recent studies have found that this small volcano contains several active
hot springs which are emitting carbon dioxide gas into the surrounding landscape.
The volcano in question is located within a remote part of the province, and is called
the Nazko volcano.
This video covers the recent eruptions from this volcano, and states the general hazard
which it poses in the future.
The Nazko volcano is located in an isolated part of central British Columbia, where it
lies 84 kilometers west of the closest major city, Quesnel.
If you go 1200 meters to the northwest of this volcanic complex, you can see two areas
of ground which are completely absent of vegetation and covered with a white rock.
The reason why these two areas have no vegetation is that they are hot springs which emit high
levels of carbon dioxide gas.
Although plants need carbon dioxide to thrive, concentrations too high are lethal.
If you were to visit these spots today, you would find low temperature hot springs which
regularly bubble as carbon dioxide is released from them.
This volume of carbon dioxide allowed for the white rock called travertine to be precipitated
over time.
The Nazko cone is unusual within Canada, as it exists due to an underlying low intensity
hotspot in the mantle called the Anahim hotspot.
This hotspot is responsible for a range of volcanic features within British Columbia.
Over the more than 15 million years this hotspot has been active, the overlying crust has slowly
moved to the west, causing its center to shift over time.
The Nazko volcano began forming 340,000 years ago, when magma from this hotspot rose through
the crust and erupted onto the surface.
When this lava reached the surface, it erupted in a mildly explosive manner.
Intermittent bombs of lava were ejected along with small volumes of ash in what is termed
a strombolian style eruption.
Since much of this ash fell back to the ground adjacent to the vent, it built a small vent
called a cinder cone.
By the time this eruption had ended, a small lava flow had traveled approximately 800 meters
and a 50 meter tall cinder cone had been constructed.
For the next 300,000 years, no additional volcanic activity occurred.
Then, 20,000 years ago, the volcano erupted once again.
However, this eruption occurred during the last glacial maximum, so the area was covered
with several hundred meters thick of ice from glaciers.
Since this second eruption occurred beneath a glacier, it created an unusual volcanic
landform typically only seen in submarine eruptions, called a hyaloclastite mound.
The 120 meter tall mound can be clearly differentiated from the rest of the modern volcanic complex,
as it has since been largely strip mined for volcanic products produced during this ancient
eruption.
For some additional context, this is what hyaloclastite looks like.
After the last ice age ended, glaciers retreated away.
Then, in 5220 BC, lava erupted onto the surface once again at this cinder cone.
Over the span of a long term eruption, potentially lasting several years, three different overlapping
vents were created.
These individual vents all contained a summit crater, which intermittently ejected volumes
of ash and lava.
Only one vent was active at a time, so three different periods of activity occurred.
Although this was the largest of the eruptions to occur at Nazko, the furthest lava traveled
from its summit was only a single kilometer.
By the time this eruption had ended, the modern 150 meter tall volcanic edifice of Nazko remained.
Although no additional eruptions have occurred since then, we know that this volcano is still
active due to its hot springs which release carbon dioxide gas.
Additionally, between 2007 and 2008, a series of several hundred earthquakes occurred near
this volcanic complex.
These earthquakes, although rather deep, were attributed to magma moving within the crust,
hinting that this volcano could erupt again.
If Nazko was to erupt again, it would pose very few hazards due to the remoteness of
this volcano.
The main hazard would be lava flows which could travel up to 5 kilometers away, and
associated wildfires that would be started whenever such an eruption occurs.
The only at risk area near this volcano is the nearby town of Nazko.
Using the US Geological Survey method of rating volcanoes, Nazko would be classified as a
low threat volcano.
The odds of Nazko erupting in any year are about 1 in 10,000.
I hope that you enjoyed this video!
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