The states of California, Wyoming, and New Mexico all have something in common. These
three states all contain a supervolcano which is still active within their borders. In New Mexico,
the supervolcano I am referring to is the Valles Caldera, which can be found
39 miles to the northwest of Santa Fe. Although it has not erupted in a long time,
this massive volcano is not extinct. This video will discuss this supervolcano in detail,
and mention what its future hazards are. The reason why the Valles Caldera exists
is quite interesting, as this volcano did not form from subduction like the Cascade Mountains,
and did not form from a hotspot like Yellowstone did. Rather, this volcano exists due to rift zone
called the Rio Grande Rift. This rift zone trends south to north throughout the western half of New
Mexico. To both the east and west of this rift zone, tectonic forces are pushing the crust apart.
As a result, the crust in this rift zone is very thin which has caused a substantial
amount of recent volcanic activity. Volcanic activity began in the Valles
Caldera vicinity around 10 million years ago. Over the next 7.2 million years,
numerous volcanoes formed tall peaks and erupted in a highly explosive manner.
Each of these volcanoes contained a separate magma chamber. Then, for an unknown region, several
long lasting magma chambers from these volcanoes merged into one incredibly large magma chamber.
For the next 1 million years, the region was eerily void of volcanic activity.
Then, 1.61 million years ago, a massive eruption took place. This eruption was 380 times larger
than the infamous 1980 eruption of mount saint helens and erupted about 91 cubic miles of lava.
Due to the sheer volume of magma erupted, a large part of the magma chamber emptied. This caused the
overlying rock to collapse downwards and fill this empty space, which formed a 7.5 mile wide caldera.
70,000 years after this major eruptive, volcanic activity resumed with an eruption of rhyolite
lava. The lava during this eruption had a very high viscosity, and as a result formed
steep slopes due to its slow movement speed. When this eruption ended, a cooled lava dome remained.
Over the next 250,000 years, about a dozen other lava domes formed within the caldera.
Then, 1.25 million years ago, the largest eruption from this volcano took place. In an eruption
that likely lasted less than a month, about 100 cubic miles of lava was erupted. For comparison,
the massive 1991 eruption of Mount Pinatubo erupted only 3% of this amount. This supereruption
created a new 14 mile wide caldera, which we refer to as the Valles Caldera. Thick ash beds from
this eruption can today be seen in the bandelier national monument to the southeast of the caldera.
After this eruption, the floor of the caldera was occupied by a lake. However, it was short-lived
as the floor of the caldera bulged upwards. Over the next 100,000 years, a large area
was uplifted by 1000 to 3000 feet which formed the tallest point of the caldera, Redondo Peak.
Since this uplift began, more than a dozen large lava domes formed at the edge of the caldera.
For an unknown reason, these eruptions of rhyolite lava have been moving in a counterclockwise
direction around the caldera. The most recent of these rhyolite dome building eruptions occurred
37,000 years ago, which created the 5 mile long Banco Bonito lava flow. This represents
the most recent eruption within the caldera. Today, the Valles Caldera is still active.
Although it is not as active as Yellowstone or the Long Valley Caldera,
you can find a number of fumaroles emitting volcanic gasses and hot springs in the region.
So, what hazards does this supervolcano pose? In my opinion, another supervolcanic eruption
is unlikely. However, any future eruption has the potential to be similar in size to the 2004
to 2008 eruption of mount saint helens and erupt lots of rhyolite lava. If a future eruption was
to occur, it would likely occur near where the Longmire TV series was filmed in the southeastern
portion of the caldera. I would put the odds of a future eruption at about 1 in 50,000. Overall,
this volcano is the most deadly but least likely to erupt within New Mexico. The Valles Caldera
volcano is rated as a moderate risk volcano. I hope that you enjoyed this video. If
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