Note: DO NOT view this video if you have photosensitive epilepsy. It contains rapid lightning flashes.
Due to the destructive eruption of the Ruang volcano which left a 13.7 square kilometer
island looking quite similar to the aftermath of Alaska's Kasatochi volcano in 2008, 1,000
people are being relocated now and another 10,000 people are being relocated later.
While all 1,000 people who lived on Ruang Island are never to return again due to the
island being too dangerous to live on, the situation for another 10,000 people who live
on Tagulandang Island is a bit more complex.
Those 10,000 people will be allowed to return temporarily to their homes if and when Ruang's
alert level is lowered and its 7 kilometer exclusion zone is reduced.
However, since that area is now considered a high risk zone, these people will all be
permnantly relocated at a later date, moving specifically to Pineleng District in Minahasa
Regency once homes and facilities are built for them.
But, this will only occur sometime after all 1,000 people on Ruang Island are relocated
with the specific date when this will occur being undetermined at this time.
And now, here are some questions my audience has about the Ruang volcano which I will now
answer.
Could you briefly describe the chain of volcanoes that it's apart of and when they formed?
The 4 active volcanoes which include Ruang are part of a chain of volcanic islands known
as the Sangihe volcanic arc.
Here, a complex setting involving relatively small tectonic plates is present that has
created two separate subduction zones, one to the east and one to the west.
In the case of the Sangihe chain, the volcanism is caused by the subduction of the Molucca
Sea Plate underneath the Sangihe Plate.
This volcanism has been ongoing from 2 to 10 million years depending on where in the
Sangihe volcanic arc you go.
What is the probability that Ruang will have a caldera-forming eruption?
I'd say fairly low for now, but the problem is that we do not know enough about the Ruang
volcano's history to even know if it is capable of producing such an eruption in the first
place.
We only know about its eruptive history since 1800.
I'd like to try and relieve people's fears that an 1883 Krakatau like eruption won't
take place, but I don't have the evidence to determine whether this will or won't occur.
However, given the rarity of such large events and the lack of significant ground subsidence,
I would lean towards this most likely not occurring.
How long does it take for an island to recover from a volcanic episode ecologically?
It depends on the biome present and abundance of nearby vegetation from other landmasses.
Thus, the main drivers of vegetation reappearing assuming that everything truly was wiped out
are bird dung and or wind blown seeds.
It can take as little as 50 years for everything to recover in the tropics such as at the Lamington
volcano or as much as 50,000 years in a desert environment, such as at the Pinacate volcanic
field in Mexico.
Could a future eruption from Ruang bridge the gap between the two islands?
Yes, as not only have recent pyroclastic flows largely traveled to the northeast, but the
water depth between the two islands there seems to only be about 9 meters or 29.6 feet
which could be filled in by future pyroclastic density currents.
Is Ruang still erupting?
Yes, as you can see in this video.
The only uncertain piece of information is if another lava dome is growing on its summit,
but I would lean towards probably, yes.
Is there a volcano in Indonesia that could in the near future, say the next decade, produce
an eruption of a similar size to Ruang's recent eruption?
Yes, Mount Awu.
I want to add that the activity at Awu has nothing to do with Ruang despite the proximity
between the two.
What was the volume of ejected ash in what I am going to jokingly call "American units",
aka olympic sized swimming pools and school busses?
520,000 olympic sized swimming pools or about 26,906,000 school busses.
If this video performs well, I will answer additional questions about Ruang in a future
video.