In the last few weeks, I have been unusually busy with things decidedly non-volcanic as the world turned quite a bit darker. Regardless I noticed that there were quite a few things going on in the volcanic part of the news, but that did not for natural reasons end up as big news items.
One thing I noticed is that the YouTube Hysterati have shifted their doom-saying from Yellowstone to Campi Phlegrei. I have wondered for a decade when the fashion trends of the hysteratis would change, seems like a war was needed for this to happen. I will come back to this in my next article, stomping hysteratis takes a few words after all.
Instead let us stick to the volcanism of the islands that ended up in my browser stream. After all, I for one love me a good volcanic island. I will below take a bit of a closer look at four of those happy volcanic islands, two of them have been covered a lot previously, but since they are doing new things, here we go.
The Azores is quite reminiscent of a slightly less tectonically active part slightly offset from the Mid Atlantic Rift and on top of a less powerful mantleplume. Basically, it is Iceland Light. Still tasty, but less frequently belching forth.
São Jorge reminds quite a bit of the Reykjanes Peninsula in that its elongated shape is caused by a regional faultline running down the length of the island. It is obviously slower at rifting than Reykjanes by quite a margin, but it is still there creating tension that needs to be relieved in a generally squirty manner.
It is also offset from the centre of the mantleplume in a similar manner, with the centre being believed to be over at São Miguel.
Regardless, for most of our readers this will set an understandable back drop to what is going on over there.
During March São Jorge has suffered a tectonic crisis that started at roughly the midpoint of the island and progressed to slowly move towards the WNW. This was caused by pent up strain, and as that was released by dilation a void was caused that sucked in magma from depth through old open deep feeder tubes.
Currently the authorities have the island at a risk level of 4, that equates that the island is in a pre-eruptive state.
The last on land eruption was the 1808 Vulcão da Urzelina eruption on the Manadas Ridge. It is claimed that the eruption started with thick greenish clouds of chloric and sulphuric acid gases together with carboxylic acid flows killed plants, I find this a bit dubious to be honest.
Yes, I believe the sulphuric part, and I could at a stretch imagine how there could be chloric gases, but carboxylic acid flows? That would be a vinegar volcano for you, so a hard no on that.
So, what may come? Currently it looks like it could erupt at around the point of where the seismic crisis started down to any point along the seismic line. We will not know the specific point until the seismicity concentrates and start to move upwards.
Will there be an eruption? Judging from the low lever seismic release, at least relatively speaking, I would say that it is 50/50 for now. It all depends on if the activity can continue like this for another month, otherwise I think this will end up being just another dyke emplacement of lava.
First of all, if you are an itinerant journalist, here is some good news for you. Taal is not one of the world’s smallest volcanoes as most news articles state, it is instead one of the largest active volcanoes on the planet.
Problem is that the island in the lake is seen as the volcano, but that is just a small vent in the much larger actual volcano that covers all of the lake, and all of the land inside of the 20 by 35-kilometre caldera. Small my…
We often cover Taal as it is progressing towards its next eruption. So far it has only done small phreatic detonations, it is still building up towards the big show.
So, I will only mention the news. The level of released SO2 has dramatically dropped from peaks well above 20 000 metric tons per day, to well below 1 000 metric tons. This seems to indicate a blockage in the geothermal system of the volcano, and those tend to be blown out sooner or later.
So, do not be to surprised if you wake up to find that there have been one or more large phreatic detonations hurling ash and gas up towards the 10km mark. Right now, I do not think this is the famous quiet before the proverbial storm.
It is time to discover a bit more about the land of volcanic plenty that is Japan, but first let us take a look at my absolute favourite newly born volcanic island, Nishinoshima.
While we have been busy gawking at other new shiny volcanic eruption this little island that could have been busy doing some landscaping of its own. The change to the volcanic cone on the island is dramatic.
The cone has collapsed on one side, and it looks like it also have collapsed inwards down into the ground in a minute caldera subsidence event. Normally this is a sign of magma reservoir drainage, or due to cold shrinkage of a hot volcano causing voids for parts of the top to fall into.
Judging from the fumarolic activity on the picture above I would instead say that it may be flank movement of the entire edifice that instead have created the edifice to fall in on itself since this also creates voids.
It is here good to remember that the island is very steep below surface, and that it as such is prone to failure.
Another sign that the island is still active is the large increase in fumarolic activity on the later photograph taken by the Japanese Coast Guard.
I am certain that what we are seeing are just a brief repose before the next volcanic phase, and even as reposes go Nishinoshima is a real cutey of a volcano.
Let us stay within the confines of Japan and move to an actively erupting volcano, and this one has the name worthy of a Japanese newhalf gangstah-rapper.
Situated in Ogasawara Island chain north of Ioto (Iwo Jima), 5 kilometres north of Kita-Ioto and 130 kilometres south of the Fukutoku-Oka-no-Ba that had a large eruption in 2021, Funka Asane is a more unknown entity.
It should not in any way be less well known. After all it is one of the most frequently erupting volcanoes in all of Japan.
It is not known if this is a new vent of the long dormant Kita-Ioto volcano, or if it is a separate volcano. Regardless, Funka Asane has an interesting history all of its own with the first recorded eruption in 1780.
After that it erupted for nine years between 1880 and 1889, with the next eruption occurring between 1930 to 1945. After that there have been 16 instances where either fishing vessels or the Japanese Coast Guard have reported steam, turbulent water, and discoloured water indicating potential smaller eruption emanating from Funka Asane.
At 06.00 Sunday the 27th of March a satellite recorded the start of a new powerful eruption at Funka Asane with ash and steam rising to 7km height. It was reported by fisherman that the eruption consisted of Surtseyan rooster-tails reaching between 300-700 meters in height.
This is a common fishing spot for Japanese fisherman, so not much happening here without getting noticed. I guess those fishermen got quite a surprise since there seems to have been no warning on the surface prior to the eruption, and the volcano is not instrumented.
Prior to the eruption Funka Asane was a shoal that barely touched the surface at low tide, so an island formation is definitely not out of the question. It also seems quite likely that this eruption will last for years at a sedate pace.
I love the smell of a fresh volcanic island in the morning.