Volcano thread

[bjdeming]

Another official source, tweeted about half an hour ago -- no changes, as I understand it; basically, activity continues, including weak, moderate, and strong pyroclastic flows; watch, wait, be prepared.

 

[bjdeming]

They also shared some amazing lahar footage:

 

[bjdeming]

Posted within the hour: "Fuego is back to being Fuego." Yay!

 

[bjdeming]

Spectacular eruption of Lewotobi in Indonesia a little while ago:



They must have seen this coming because authorities evacuated areas again, starting weeks ago.

VAAC advisory describes ash at 53,000 feet, per Volcano Discovery, which has earlier news links, too.

 

[bjdeming]

Here's another view. Per X translation: "Mount Lewotobi eruption this afternoon, June 17, 2025. Video taken from Pululera village which is 7 KM from the center of the eruption. Video source: Pululera Village Head."

 

[bjdeming]

Nice weather for it!

 

[bjdeming]

Tribun Flores has some nice shots, though shaky-cam, of the start and then some plume development:



That's a livestream, started about an hour ago -- don't know how long it will be good.

Edit: Much of the footage is replays, thus far -- good! Maybe it was just a blast, not a self-sustaining plinian eruption.

 

[bjdeming]

It sounds (Indonesian) as though Lewotobi is following its past pattern of an intense start and then lower-level activity.

Per browser translation, the main threat now is lahars, if and when the weather turns rainy.

 

[bjdeming]

Heads-up post on Japan's Tokara Islanda, though as mentioned I'm not sure it's volcanic or seismic trouble.

Also, much farther up the Kagoshima graben, on Kyushu and just north of Sakurajima, Shinmoedake in the Kirishima Mountains erupted (Japanese) for the first time in seven years but Dr. Imura tweets that it has stopped now.

 

[bjdeming]

Just found this Weather News article (Japanese) on the Tokaras (and also on the seismic situation near Hokkaido).

Re: the Tokaras, via browser translation --

...The coastal waters of the Tokara Islands are an area where swarms of earthquakes often occur. This is the first time since June 2024 that more than 10 perceptible earthquakes have been observed in a single day, when the largest earthquake was a magnitude 3.7 earthquake with a maximum seismic intensity of 3.

The activity in May 2023 was a maximum seismic intensity of 5-, and the activity in December 2021 was a maximum seismic intensity of 5-strong. In some cases, the earthquake-prone situation will continue for several weeks or more, so it will be necessary to keep an eye on developments for a while.

<Layerperson speculation> It might be impossible to tell whether submarine quakes are tectonic or volcanic in origin. With the complex situation here -- subduction-related stress field on one side of the Tokara Strait and extension-related stress on the other side, plus volcanoes scattered all over, above and below the waves, either is possible. <Layperson speculation>

 

[bjdeming]

Also, this happened 16 years ago -- the image is often attributed to other volcanoes. Here's the real thing.

 

[bjdeming]

They just raised the alert again at Shinmoedake, that volcano north of Sakurajima in the Kirishima Mountains:

Via Google Translate:

The amount of volcanic gas emitted from Shinmoedake in the Kirishima mountain range, which lies on the border between Kagoshima and Miyazaki prefectures, has increased sharply, and the Japan Meteorological Agency, citing further increased volcanic activity, issued a new crater area warning at 6:30 pm on the 23rd and raised the eruption alert level to 3.

It is calling for caution against large volcanic rocks and pyroclastic flows within a 3-kilometer radius of the crater...

-- Source (Japanese)

Here it is in 2011:



And in 2018:



It had a role in You Only Live Twice.

The mountains are complex, in volcanic terms.

 

[bjdeming]

Hazards graphic on Mount Kirishima/Shinmiedake (I can't read the image text):



It's rather remote, for Japan, and in the most recent eruptions ash was the main problem, I believe, for surrounding communities. Lahars would also be a concern in rainy weather, which is part of Japan's life right now, including an approaching tropical system (though ? if Kyushu is in the landfall area).

However, current news stories that I've come across say that local school children are wearing hardhats now (they do this on Sakurajima, too).

Edit: Okay, large ballistics and pyroclastic flows, too. Dr. Imura is interviewed as part of this article (Japanese).

 

[bjdeming]

Tokara news update: nothing major but interesting, and because it's so complex (a volcano is involved, but...), these two blog updates will have to do:

June 23, 2025, 9:39 p.m., Pacific: I had thought the Tokaras were south of Kikai — and some of them are — but it turns out that frequently active Satsuma volcano, on Kikai’s rim and not close to the probably tectonic seismic swarm, is one of them, and it emitted a white plume today.

Per the Global Volcanism Program Kikai page:

Multiple eruption centers have exhibited recent activity at Kikai, a mostly submerged, 19-km-wide caldera near the northern end of the Ryukyu Islands south of Kyushu. It was the source of one of the world’s largest Holocene eruptions about 6,300 years ago when rhyolitic pyroclastic flows traveled across the sea for a total distance of 100 km to southern Kyushu, and ashfall reached the northern Japanese island of Hokkaido. The eruption devastated southern and central Kyushu, which remained uninhabited for several centuries. Post-caldera eruptions formed Iodake (or Iwo-dake) lava dome and Inamuradake scoria cone, as well as submarine lava domes. Recorded eruptions have occurred at or near Satsuma-Iojima (also known as Tokara-Iojima), a small 3 x 6 km island forming part of the NW caldera rim. Showa-Iojima lava dome (also known as Iojima-Shinto), a small island 2 km E of Satsuma-Iojima, was formed during submarine eruptions in 1934 and 1935. Mild-to-moderate explosive eruptions have occurred during the past few decades from Iodake, a rhyolitic lava dome at the eastern end of Satsuma-Iojima.

Per the Japanese Meteorological Agency, via Volcano News:

Activities of Satsuma Iwo Jima
Crater Area Warning (Eruption Alert Level 2, Crater Area Restrictions)

Interpretive information on the status of the volcano

June 23, Reiwa 7, 16:00 Fukuoka Regional Meteorological Observatory / Kagoshima Regional Meteorological Observatory announcement

Status of volcanic activity
At Iwo-dake crater, a white plume rose up to 400 m above the crater rim.
At night, we occasionally observed the fire with high-sensitivity surveillance cameras.

Volcanic earthquakes have passed in a low number. No volcanic tremor was observed.

In the long term, there is a possibility that an eruption will occur to a degree that affects the area around the crater due to the continued state of increased thermal and plume activity, such as the observation of a fire at night and occasional high plumes.

If there is any connection between Satsuma’s plume/glow and the Tokara seismic swarm — a big and very unlikely “if” — it would probably be that Satsuma was getting ready for another eruption anyway and the shaking either has unsettled it or speeded up the process.

Still, the area is populated and popular with tourists, and Satsuma might go off, so I’ll pin this now — under “Tokara” NOT “Kikai” (which is a whole ‘nother and currently dormant thing). There is no need to mobilize the pop-music contingent.

June 22, 2025, 10:48 p.m., Pacific: Some technical (but unofficial) posts on X suggest to this layperson that the swarm is tectonic, including this one:

...

イクスリップ型に近いが、最大のM5.2（22日17:15）とその前のM3.9は正断層型。共通するのは北西・南東伸長のメカニズム。M5.2の次の逆断層に見えるのはCMTの決め間違いかもしれない。 pic.twitter.com/Cdtsfo7F4N

— hacchan9642 (@hacchan9642) June 23, 2025

https://platform.twitter.com/widgets.js

X translation (emphasis added): “F-net has found many CMT solutions for the earthquakes off the coast of the Tokara Islands, which continue to have a seismic intensity of 1 or higher. Many of them are close to strike-slip type, but the largest M5.2 (17:15 on the 22nd) and the previous M3.9 are normal fault types. What they have in common is a mechanism of northwest-southeast extension. What appears to be a reverse fault following the M5.2 may be a misdetermination of the CMT.”

Extension is something we’ve recently seen in another complicated tectonic setting loaded with volcanoes: the more powerful Amorgos seismic swarm near Santorini and Kolombo in the Aegean Sea

And it settled down without any associated eruption. Perhaps this latest round of Tokara Islands quakes will, too.

 

[bjdeming]

Shinmoedake: This is promising -- it might have just been a phreatomagmatic blast.

Via Google Translate: (Japanese)[/quote]

Experts analyzed the volcanic ash that fell during the eruption of Shinmoe-dake in the Kirishima Mountains on the 22nd and found that it contained almost no material related to new magma.

While experts said it was likely a "steam eruption," they also pointed out that it is necessary to keep a close eye on future developments...

-- Source (Japanese)

The amount of gas reported by JMA has dropped but it's still rather high, and there is some ground deformation -- from a deep source, if I understand them correctly.

 

[bjdeming]

Shinmoedake erupted about six hours ago, but the clouds are so thick -- there's a landfalling tropical system to the north -- that they only knew it from light ashfall.

Seismicity is very frequent, per JMA (updates are here), which this layperson sees as a sign that magmatic eruption is either beginning or likely to follow.

Dr. Imura, one of the volcano's millions of human neighbors, sums up the prospect succinctly:




"Translated by Grok...

The eruption of Shinmoedake starting with a phreatic explosion is, well, common knowledge. The issue is whether it will progress to a magmatic eruption. When will it happen? And if it does, will it be Plinian? That’s the question. The eruptions in 1954 and 1991 were only phreatic explosions. In 2011, it was a magmatic eruption with a Plinian (or rather, sub-Plinian) scale. In 2018, it was a magmatic eruption without a Plinian phase."

 

[bjdeming]

Dr. Imura took to the air today -- apparently with the assistance of a news agency (Japanese, not autotranslated in order to get the video to play) -- and checked out Shinmoedake, which is still having a fissure eruption, per JMA.



X translation: "The area rising higher than the surrounding clouds is beneath Shinmoedake. Volcanic ash is flowing to the left (northwest) side. Slightly to the left of the center at the bottom of the screen is Takachiho Kawahara, and on the right at the bottom, the slope of Mihachi is visible."

-------



"I took a shot with the FLIR (https://x.com/tigers_1964/status/1077482208577826816…) that I got from 「ひできち」. Since the distance is far, I don’t think the temperature values hold much significance, but that white thing beyond the northeastern crater rim seems to have a higher temperature than its surroundings."

But my favorite tweet, posted at the same time was this:




"Sakurajima right now.I'm fully aware I live in an incredible place."

So do I, but the volcanoes don't erupt nearly as often.