The title for this video is quite accurate. I am a geologist and can confirm that it is correct.
According to the smithsonian institution, 4 volcanic eruptions have occurred in the last
10,000 years at Yellowstone, which 1 of these occurring in the last 5,000 years.
Although these recent eruptions in question can be quite deadly,
they are NOT the cataclysmic style eruptions which are often glorified in Hollywood disaster films.
Rather, these eruptions are 5 to 6 orders of magnitude smaller than supervolcanic
eruptions. This video will discuss these recent eruptions, and discuss their future hazard.
Look at these 4 ponds. They may seem harmless at first, unless you realize
that these are all explosion craters. These ponds are the remnants of very large
hydrothermal explosions which occurred in the last 10,000 years. The craters range in width
from 400 meters wide to 1000 meters wide. A diagram is being shown on screen which
contains the width and approximate year these craters formed.
These large hydrothermal explosions are called phreatic eruptions. What is a phreatic eruption?
A phreatic eruption is a steam-driven explosion that occurs when water beneath the ground
or on the surface is heated by magma, lava, hot rocks, or new volcanic deposits. The intense
heat of this nearby material (can be 1000 C+) may cause water to boil and flash to steam,
thereby generating an explosion of steam, water, ash, blocks, and bombs. This style of eruption
does not erupt any lava, but is still considered to be a dangerous type of volcanic eruption.
To truly determine the scope of these eruptions, I decided to perform some calculations using
triple integrals. I specifically looked at one of these craters which is called "Duck Lake". This
explosion crater has a width of 560 meters and a length of 380 meters. It has a maximum depth of
18.3 meters. Due to its size, it makes sense that an explosion that created a crater of this
size would have thrown a lot of rock and ash into the air. For these calculations, I made a series
of logical assumptions due to some incomplete data. My final result contained two estimates.
This volcanic explosion threw between 1.4 million and 1.6 million cubic meters of rock into the air.
On the 8 point Volcanic Explosivity Index which is used to rate
the size of a volcanic eruption, this would be rated as a 2.
A well documented example exists of a recent volcanic eruption which was almost
identical in size to the one that produced these explosion craters in Yellowstone. The thumbnail
which I used for this video shows this volcanic eruption, which occurred in 2019 in New Zealand.
In 2019, the White Island volcano in northern New Zealand violently exploded in a phreatic
eruption. This eruption created a large plume of ash which went 3700 meters into the air. The
ash did not contain any lava, but was rather was pulverized fine particles of rock produced by the
explosion. This eruption killed 21 tourists who were on the island at the time of the explosion.
Due to this eruptions similar size to previous Yellowstone explosions, the eruption provides
some cautionary lessons for what will likely occur again at Yellowstone. According to the USGS, a
hydrothermal explosion that creates a crater more than 100 meters wide occurs about every 700 years.
This simply means that every year, the chance of an eruption of this type is 1 in 700.
As a result of this hazard, the US Geological Survey has classified this
volcano as a high threat. This is not the highest threat category, but still
indicates a volcano that could cause economic damage or deaths if it were to erupt again.
It is worth mentioning that despite all of this,
it is quite safe to visit Yellowstone national park. I have visited this
national park before and recommend it to anyone who likes wildlife or geology.
If a hydrothermal explosion was to occur again, the geologists who work in this park
would most likely notice warning signs beforehand and close off the park.
In the description below, I linked a series of papers and scientific articles which I used as
sources for the creation of this video. I hope that you enjoyed this video.
If you would like to request a specific topic, please leave a comment below!