Note: DO NOT view this video if you have photosensitive epilepsy. It contains rapid lightning flashes.
On April 17th and then again on April 30th, Indonesia's Ruang volcano produced powerful
plinian eruptions which absolutely devastated the 13.7 square kilometer island it sits on. Luckily,
scientist warnings allowed for quick evacuations to be made, and despite every single one of the
more than 200 structures on Ruang Island along with every single spot of vegetation being
completely incinerated, no lives were lost. However, due to a combination of the heavy
rate of ashfall which occurred alongside lava bombs and lapilli falling from heights upwards
of 60,000 feet, hundreds of additional structures were damaged on the adjacent Tagulandang Island.
With a 7 kilometer exclusion zone still in place which is likely to remain for some time,
the government of Indonesia has arrived at a decision. Approximately 1,000 people are never to
return to the most effected area, meaning everyone who formerly lived on Ruang Island. As a result,
the government of Indonesia is building hundreds of homes to accommodate those displaced residents
although this will take some time. What is essentially a declaration of a permanent exclusion
zone that displaces all who live within a certain radius at a volcano has occurred at least two
other times in the 21st century in Indonesia; at Mount Merapi in 2010 and Sinabung in 2015 to 2016.
This is all because the Ruang volcano has proven to be far more dangerous than previously thought,
with its recent eruptive activity suggesting that a far larger magma chamber is present
and even potentially an ancient caldera. While many people are still debating the exact
size of Ruang's eruption which just occurred, some people asked how I arrived at my estimate
of its eruption size. To answer that question, it involved estimation, a simple conversion, and
eyeballing various parameters the eruption had. For example, Ruang's two plinian eruptions most
likely released 1.3 million metric tons of sulfur dioxide gas with estimates ranging from 500,000 to
1.5 million metric tons. Generally speaking, the amount of sulfur dioxide released is a semi decent
indicator of how much magma an eruption involved. By comparing it to the general rule of 1.3 million
metric tons of sulfur dioxide being released for each cubic kilometer of tephra ejected,
it would appear that around 1 cubic kilometer of tephra was released. However, my figure said 1.4
cubic kilometers, so how did I arrive at that larger figure? For that I used a conversion
from the estimates the AIRES account on x posted which monitors activity from satellite. They noted
releases of 0.20 and 0.47 cubic kilometers of what is called dense rock equivalent, or the compact
magma involved in the April 17th and April 30th eruptions respectively. I then eyeballed footage
of the vulcanian explosion which occurred on April 30th after the plinian phase ended,
giving an estimate that 0.03 cubic kilometers of dense rock equivalent was involved in that event.
When you add these 3 figures together you get a dense rock equivalent of 0.70 cubic kilometers.
Just so I can remind everyone, dense rock equivalent and bulk tephra figures are not the
same thing. This is due to a set volume of magma producing a larger amount of uncompacted ash due
to the way it forms and the numerous air bubbles tephra contains. While dependent on composition,
andesite composition lava generally has a density of 2.6 grams per cubic centimeter while andesite
composition ash has a density of about 1.3 grams per cubic centimeter. Thus, we multiply the prior
DRE figure by 2 to get 1.4 cubic kilometers of tephra since Ruang's eruption was andesitic.
As a final note, for tomorrow's video I will answer a list of questions that you, my audience,
have about the Ruang volcano, its current situation, and its recent eruptive activity.