When people think of California, they tend to not think of volcanoes.
Yet, the state contains about a dozen active or dormant volcanoes which could erupt again.
Much of the volcanoes within California are located within Mono County in the eastern
portion of the state.
Specifically, the county contains a 30 mile or 48 kilometer long line of recent volcanoes
which trend northward all the way from Mammoth Mountain in the south, Mono-Inyo craters in
the center, and Mono Lake to the north.
Within the last 2,000 years, these volcanoes erupted more than a dozen times.
This video will discuss these volcanoes, and will mention their future hazards.
Additionally, I will state the odds per year of this volcanic series erupting.
For this video, we are defining an active volcano as any volcano or volcanic field which
has erupted in the last 10,000 years.
The first group of volcanoes we will cover are the Mono-Inyo Craters.
On google earth, I color coded these volcanoes with a pink marker.
As we zoom in from satellite, you can make out a number of volcanic features.
In the south, there are a series of four explosion craters.
These explosions craters formed in about 1380 from a series of phreatic eruptions, and did
not erupt any lava.
The rest of the volcanoes in this field are lava domes, and they are gorgeous.
For example, the south deadman creek lava dome formed about the same time as the aforementioned
explosion craters.
The lava and explosion dominated eruptions from this feature created a beautiful 4500
foot wide and 350 foot tall lava dome.
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.
As we go northward, you can see at least two dozen different lava domes.
Some of these lava domes built on top of one another, while others occured in isolated
spots within the volcanic chain.
Of these, the vast majority formed in the last 10,000 years.
The northern most feature in this volcanic field is the Panum dome.
It formed in two phases.
First, a massive explosion occured which formed a 2200 foot wide crater.
After the explosion, a lava dome started to form at the bottom of the explosion crater.
This eruption, series occured in the year 1350.
The total size of this eruption was probably 1/5 the size of the explosive eruption of
Mount Saint Helens in 1980.
The northern-most section of this line of volcanoes is the Mono Lake Volcanic field.
As the name implies, all of the volcanic eruptions in this volcanic field occured within the
lake or on its northern shore.
With this being said, the lake itself was not formed by a caldera collapse from a volcano.
The lake just happens to have volcanoes in it.
Within the last 10,000 years, a series of eruptions formed or added to two distinct
islands within the lake.
The most recent of these eruptions occured in about 1790 on Paoha island, although there
may have been volcanic activity occuring as recently as 1890.
So, what is the hazard posed by these two volcanic fields?
Both of these volcanic fields produce dominantly explosive eruptions, with some of them being
classified as cataclysmic in size.
As a result of this hazard, the US geological survey assigned the Mono-Inyo craters a high
risk designation.
About 10,000 people live within 20 miles of this volcanic field.
As for the Mono lake volcanic field, the US geological survey assigned it a moderate risk
designation.
The eruptions from this volcano are smaller than its companion field, and not as many
people live in the nearby vacinity.
Overall, the odds of a volcano in this area erupting is about 1 in 200 each year.
I hope that you enjoyed this video.
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