The state of California has several volcanoes which are classified as active.
Of these, the most recent volcanic eruption occured from Lassen Peak in 1917.
However, another part of the state has a high chance of a future volcanic eruption.
This video will cover an active volcano in the central part of the state.
The volcano in question is the only volcano in California which has caused fatalities.
I am referring to the Mammoth Mountain volcano.
For this video, we are defining an active volcano as any volcano or volcanic field which
has erupted in the last 10,000 years.
Mammoth Mountain occurs is the central eastern part of california, and is a mere 2 miles
west of the resort town of Mammoth lakes.
The region where Mammoth Mountain is located is filled with numerous examples of recent
volcanic activity.
This volcano is the southernmost feature in a 30 mile or 48 kilometer line of recent volcanoes
which trend northward all the way to Mono Lake.
At first glance, the over 11000 foor tall mammoth mountain may look like a stratovolcano.
However, it is not that type of volcano.
Much like Lassen peak in northern california, Mammoth mountain is a large lava dome complex.
Lava domes form when viscous lava builds in a central location due to its slow movement
speed.
This eventually forms a rough looking shape which resembles the upper half of a sphere.
From satellite, you can see the rough outline of several spherical features on this volcano
which are the lava domes.
The vast majority of this mountain formed 57,000 years ago.
However, it is by no means dormant.
In the last 10,000 years, two distinct volcanic eruptive episodes occurred.
The most recent of these were phreatic explosive eruptions which occured around the summit
in the year 1260.
These explosive eruptions occured when rock heated from nearby magma causeded water in
the volcano to flash to steam and explode.
This style of eruption does not produce lava, but is still rather dangerous.
4 such explosions occured in a relatively short period near the volcano's summit.
The older eruptive phase in the last 10,000 years produced two distinct cinder cone volcanoes
in 6540 BC.
These red colored cinder cones lie 3 miles southwest of the volcano.
Cinder cones form when lava essentially shoots straight up, and small explosions throw pieces
of ash into the air.
This lava then builds up around the eruptive vent.
For the thumbnail of this video, I picked a photo of a cinder cone from Kilauea in Hawaii
erupting.
Since no videos or photos exist of Mammoth mountain erupting, I chose to show what a
non explosive volcanic eruption that produced these two cinder cones might have looked like.
These recent eruptions are not the only hazards posed by this volcano.
Due to the presence of magma relatively close to the surface, the volcano produces very
high amounts of carbon dioxide at several points around the mountain.
Do you see these dead trees?
These were not cut down for logging, or killed by insect infestations.
Rather, these trees died due to dangerously high levels of carbon dioxide in the area.
If you look around the mountain, you can find about a dozen examples of similar tree kill
sites.
You might say, but wait, plants need CO2 for photosynthesis.
This is true.
However, plants also need a good amount of oxygen to cause respiration for plant growth.
Too much CO2 in the air prevents this, and thus kills the plant.
The high levels of CO2 do not pose a threat to only plants.
When carbon dioxide from soil leaves the ground, it normally mixes with the air and dissipates
rapidly.
However, carbon dioxide is heavier than air.
As a result, it can collect at high concentrations in natural valleys or depressions around the
mountain.
This hazard becomes even more pronounced when the carbon dioxide gets trapped beneath dense
snowpack.
Breathing air with more than 30% CO2 can quickly cause unconsciousness and death.
Sadly, this hazard has caused both suffocations and deaths.
The most recent deaths caused by excessive levels of CO2 occured in 2006.
As a result of this hazard, several grids of sensors have been set up to constantly
measure these levels.
At times, areas of the mountain may be closed off from skiing due to this.
So, what is the hazard posed by Mammoth Mountain?
According to the most recent hazard assessment by the US geological survey, Mammoth mountain
was classified as a moderate threat volcano.
The chance of a future eruption is relatively low, but in the immediate future it is elevated
due to the 1000 tons of carbon dioxide which the volcano produces every day.
If an eruption was to occur, odds are that it would be explosive in nature.
Such an eruption could pose a hazard to the skiiers that frequent this mountain, and the
nearby town of Mammoth Lakes.
With this being said, I would still feel safe visiting this mountain and its nearby town.
To stay safe, do not camp at any natural low points in the region, and do NOT stay in an
area with lots of dead vegetation for an extended period of time.
I hope that you enjoyed this video.
If you would like to request a specific topic, please leave a comment below.