Because of the internet and the fact that approximately two thirds of individuals on
the planet own mobile phones, it does not take long for the rest of the world to learn
that a natural disaster has occurred in a distant place.
For example, when a deadly volcanic eruption somewhat unexpectedly occurred at the Democratic
Republic of the Congo's Nyiragongo volcano in 2021, I was personally informed by a viewer
of mine within the first 10 minutes.
Or, in a completely unpopulated Antarctic island volcano known as Mount Michael, I can
view from satellite evidence that a volcanic eruption is ongoing.
Because of this, you might think that it would be quite easy to tell when a large volcanic
eruption occurred on an island with a population of 300,000, several thousand of which live
within eyesight of its peak.
Yet, when the Bagana volcano on the island of Bougainville produced a major explosive
eruption on July 7th, 2023, sending a plume of ash to a height of 17,400 meters or 55,000
feet, the outside world and detection symptoms meant to detect this sort of thing completely
missed it for nearly 48 hours.
VAAC, which is the international warning system meant to advise commercial and private aircraft
of ash clouds and their location so they can avoid them, was created after two large passengers
jets had all 4 engines fail due to the ash from a fairly close volcanic eruption, although
these two aircraft were landed safely without casualties.
Only a relatively minimal amount of airborne ash is needed to potentially cause a similar
circumstance.
This is why it is quite worrying that such a large ash plume that formed on July 7th
was only detected in post processing on July 9th 2023 due to the work of several scientists.
Later work confirmed that Bougainville's Bagana volcano generated this plume.
The missed immediate detection of this event was not caused by incompetence or corruption
in my opinion, but rather due to the fact that the ash plume was almost completely obscured
by several layers of thick cloud cover.
One reason a disaster did not thankfully occur is that the rainforest covered island of Bougainville
sees very little air traffic, and is not frequently used as a location flown over by major commercial
airlines.
Yet, if a data gap existed around the Bagana volcano, even temporarily, it calls into question
whether other such data gaps might exist elsewhere on the planet.
As for Bagana's eruption which reportedly triggered the evacuation of 8,000 people,
here is what we do know.
At around 10 pm local time on July 7th 2023, an unusually powerful explosive eruption generated
an eruption plume between 16 and 18 kilometers in height.
As the ash plume drifted away, large amounts of ash fell across sections of the landscape,
which although an exact figure was not given for the ash thickness may have been more than
a centimeter thick.
Many open water sources were contaminated, numerous gardens and crops were ruined, and
approximately 11,000 tons of sulfur dioxide was produced by this event.
The 11,000 tons of sulfur dioxide and the height of the gray ash plume would be somewhat
consistent with a borderline low end VEI 3 explosive volcanic eruption.
This represented Bagana's largest explosive eruption since 1966, a full 57 years during
which it has almost been continuously erupting.
The Bagana volcano is a highly unusual and fairly rare type of volcano known as a "lava
cone".
Unlike a typical stratovolcano which consists of alternating layers of lava and ash which
is generally around half of each, a lava cone consists almost entirely of very numerous
lobes of viscous andesite or dacite lava.
For some reason, lava cones aren't as seemingly volatile and gas rich as might be expected
given their lava compositions.
Thus, while Bagana has produced vulcanian explosions with some pyroclastic flows, these
seem to occur only around a half dozen times a year with its vulcanian explosion generated
eruption plumes rarely reaching more than 10,000 feet into the atmosphere as its eruptions
are for the most part only effusive to moderately explosive.
Bagana seemingly started forming only right after the pyroclastic shield volcano known
as Billy Mitchell 6 kilometers to the northeast collapsed into a caldera in a major 1580 CE
explosive eruption.
Although we aren't exactly sure of this, some evidence suggests that this eruption removed
the most volatile rich components of Billy Mitchell's vast underlying magma chamber which
ever since has been almost completely directed to grow the Bagana lava cone.
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