I am sad to report that the first deadly volcanic eruption of 2023 just occurred, meaning it
produced casualties.
As, at 2:54 pm local time in Indonesia on December 3rd, the Marapi volcano on the island
of Sumatra erupted without any warning beforehand.
This explosion threw superheated boulders of rock, lava, and ash over a several hundred
meter radius, while also sending a plume of ash to a height of 5,900 meters or 19,400
feet.
However, since part of the eruption column was much heavier than the surrounding air,
the force of gravity caused it to collapse back to the ground and generate a 500 degrees
Celsius pyroclastic flow.
Within 60 seconds, this pyroclastic flow traveled 3 kilometers to the north and then northwest,
incinerating about 0.9 square kilometers of dense forest.
1 centimeter wide particles of rock known as lapilli from the eruptive plume then began
to fall on the town of Bukittinggi 11 kilometers to the northwest.
Sadly, at the time, 70 people were actively climbing the Marapi volcano which is the 10th
highest peak on the island, and at the present at least 11 of those individuals are now confirmed
as deceased, presumably due to the pyroclastic flows and ballistic projectiles the eruption
created.
While the vast majority of those individuals have been accounted for, there are still approximately
a dozen people who are still missing, although this total might change by the time this video
is published about 24 hours later.
What had just occurred was Marapi's largest single eruption in its recorded history, and
since a tragedy occurred, many people are likely looking for answers and someone to
blame.
However, I have an uncomfortable truth.
According to my source there was no negligence on the part of the local disaster agencies,
Marapi as a whole was already well monitored, and the equipment on the volcano was working
fine.
Marapi during the last few weeks produced absolutely nothing notably above its baseline
seismicity, ground deformation, gas emissions, or temperatures until all of a sudden the
eruption began.
In other words, the latest eruption was completely unpredictable with our current technology
with no warning signs missed beforehand, meaning no persons or organizations were to blame.
The scary truth is that sometimes volcanoes can just unexpectedly erupt and there is absolutely
nothing you can do about it as volcanoes can occasionally behave in a completely unpredictable
manner.
While uncommon, if you climb a volcano, there is always a very small but technically possible
outcome that it could unexpectedly erupt with no warning signs beforehand.
It is a sad reality but a danger that everyone should know.
However, certain volcanoes are more likely to produce unexpected eruptions than others.
To name a few similar tragedies, something similar occurred when Colombia's Galeras volcano
unexpectedly erupted in 1993, causing casualties among several people including a team of volcanologists
who were actively studing the volcano.
However, I feel that a more similar example was the unexpected large phreatic eruption
of Japan's Ontake volcano in 2014, which without warning erupted, producing pyroclastic flows
that caused dozens of casualties among hikers on what was a volcano at the lowest alert
level at the time.
In those two aforementioned cases, along with what just occurred, the eruptions appeared
to have a major phreatic component to them.
In other words, magma in the crust either in the short or long term heated overlying
rock, which subsequently transferred some of this heat to overlying groundwater.
The groundwater then flashed to steam, and since the same mass of steam takes up more
than 1,000 times the volume of the water it once was, it causes an immense amount of pressure
to build.
Eventually, this pressure reaches a critical point that it breaks overlying rock, creating
a powerful explosion which in the case of Marapi's latest eruption also ejected some
deeper fragments of magma.
This entire process can sometimes occur at such a slow rate that it is not detectable
with our current technology.
Small amounts of ash fell in towns surrounding the Marapi volcano, and since the eruption
began a total of 45 volcanic explosions have occurred.
While Marapi technically was at a yellow alert level at the time and had an exclusion zone
of 3 kilometers in all directions around its main crater, hikers were regularly allowed
to climb the volcano and bypass the exclusion zone.
If hiking or climbing Marapi is not completely forbidden after this tragedy, I suggest a
similar change to what was made after the 1993 Galeras Tragedy in Colombia.
Namely, require those that hike or climb Marapi in the future to wear a hard hat and fire
resistant clothing, as well as post numerous signs warning of the now known danger that
an unexpected and unpredictable volcanic eruption could occur without warning.