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Volcano thread

Dr. Hayakawa is a renowned volcanologist, retired now, I believe; Dr. Imura we have met. Both are knowledgeable but unofficial.

Hayakawa shows his interpretation of the fissure line, as of about half an hour ago.

Imura says, per X translation: "I wonder if it really spread toward the southwest (toward the center)? The northeastern crater rim feels like it has a small cone formed right at the edge, rather than the eruption fissure extending beyond the crater rim. I want to properly observe it from above."



Will see what JMA says today; it probably doesn't need a thread unless they go to 4, which requires evacuation of vulnerable people. The highest level, 5, calls for everybody in an affected area to evacuate.
 
JMA is keeping the alert at Level 3.

In this tweet, Dr. Imura confirms that a crater has opened outside the summit crater rim. The drone image in the retweeted post was taken shortly after the ash emission intensified yesterday. Dr. Hayakawa thought it was AI at first!



Per the GVP, population around this volcanic complex is:

Within 5 km
Within 10 km
Within 30 km
Within 100 km		647
8,415
407,050
3,972,044
 
This paper gives us an idea of the sorts of things that officials and scientists are probably taking into account.

It focuses on Sakurajima and a hypothetical repeat of the 1914 VEI 4 Taisho eruption, but the Kirishimayama complex is close to the north shore of the bay that Sakurajima sits in, and this layperson can't see that it would make much difference if the location of the plinian-style eruption was there instead of at old "Cherry Blossom Island."

That is, apart from most of the ash falling on land, whereas Kagoshima Bay would take in much of Sakurajima's ashfall next to the volcano. On land, more ash would lead to more lahars and other short- and long-term problems.

No one can know yet if this Shinmoedake eruption will escalate to plinian levels, but just in case, it's an interesting paper.

Of note, in discussing their model the researchers note:

...It remains necessary to evacuate all vulnerable communities ... before of a large-scale explosive eruption, using the most reliable prediction results. However, the varying degree of uncertainties existed due to the time of the prediction and the quality of the wind forecast data influence the decision-making time frames. Following the current policy, forcing early evacuation orders (24 hr before an eruption) in most cases will result in a considerable number of unaccounted casualties and forced evacuees. Meanwhile, a delayed decision can also lead to fatal consequences due to late immobilization of residents. Uncertainties reside in each prediction state should be taken as a crucial input to select the most appropriate time for issuing a city-wide evacuation. The correct decision timing can ease the response planning, including the provision of additional shelters, the preparation of a greater quantity of relief goods, and the management of increased traffic flows, all of which can accrue substantial monetary costs...
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Thank you, James T. :)

Also, Weather News reports (Japanese) that the uptick in activity that began late this afternoon (local time) continues.

It's raining, too, but there isn't yet enough ashfall AFAIK to soak it up into roof-breaking weight levels. Dr. Imura notes that the ash is washing into rice paddies.

As lagniappe, JMA has raised Aso's level to 2. Aso -- Nakadake Crater, actually -- is tens of miles north of Kirishimayama and in a different tectonic feature, not the Kagoshima Graben.

The eruption shown in the first post of this thread is from Nakadake.
 
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Somehow stumbled through the language barrier to a list of live cams (Japanese) hosted by Kirishima City. Can't see much right now because of weather and night, but hopefully there will be some decent views tomorrow.
 
 
Re: Shinmoedake. In some respects, it is like a high-stakes soap opera. ;)

The volcano still doesn't seem to be doing much but it is doing so in a very unstable way, venting from the whole fissure, or the northern end of the fissure or the southern end, venting a lot, venting a little.

The Geological Survey of Japan (GSJ) reports that the volcano is expelling old lavas from 2011 and 2018. Yet TROPOMI is reporting SO2 emissions (SO2 is vented by fresh magma that's relatively close to the surface, whereas CO2 -- for example, as detected these days at Campi Flegrei -- comes from greater depths; this degassing is partly dependent on pressure).

Dr. Hayakawa is fulminating because he feels the situation at the crater is critical and JMA has scheduled its next update for Monday afternoon. Dr. Imura sounds as though he wants to take to the air again with IR and thermal imagery, and I hope he gets his wishes.

<Layperson speculation> I agree with the Internet person who described the situation as feeling like something underground is trying to find a way out.

The Kirishimayama complex has its own plumbing system but it is also quite close to Aira caldera, under Kagoshima Bay, and I have read a few opinions that Aira sometimes contributes to Kirishimayama eruptions.

If this is so, then the thing rustling underground, trying to get out, might be Aira, "wanting" to stage another 1914-Taisho-style VEI 4 but possibly unable to do so again at Sakurajima, on Aira's south rim, because of Sakurajima's open venting since the 1950s -- can't get enough pressure up for that.

So perhaps it is putting the squeeze on Shinmoedake now. But AFAIK it doesn't have any established magmatic link to that volcanic system. Yet.

Time will tell.

It's quite possible that Shinmoedake is clearing its throat and could escalate at any time. I hope it doesn't. It's also possible, though it currently seems less likely, that this will all settle down. I hope this happens.

In the meantime, almost four million people need to stay on their toes because, if trouble comes, it will come fast.

Stay tuned for the next episode...

</Layperson speculation>
 
Didn't take long :)

This actually isn't new today; he tweeted about a second row yesterday but I missed it until Dr. Imura retweeted this, recorded during one of Shinmoedake's more intense emissions:



The upper left one.

X translation of his comment: "The depression at the center of the 2018 lava crater is visible. Inside the summit crater of Shinmoedake, there is a 200m fissure crater row extending from the northeast toward the center, and another fissure crater row has formed along the inner southeast rim of the summit crater."

Also, it sounds like Dr. Imura will be going up tomorrow, if Kagoshima Airport is open. Shinmoedake has forced many flight cancellations, but about four hours ago, Sakurajima, on the other side of the bay/caldera, joined in with a moderate vulcanian blast.
 
Lewotobi had another big blast, an 18-km plume and with pyroclastic flows out to 5 km, per Indonesia's geological agency:



No casualties are reported.

Going again by Tribune Flores' live coverage, this is not a sustained eruption, fortunately. But one wonders what's going on down there that such mighty blasts can only relieve temporarily...
 
Here's another view:

 
Shinmoedake: Dr. Imura made his flight yesterday, but I just discovered there was a news video, too. Per YouTube autotranslation, it is all info already shared from his X account -- the second fissure, the new crater outside the old one, "phreatic" (the term that Dr. Hayakawa isn't fond of here).

The crater views are terrific!



Translation is a little choppy where he's talking while on the helicopter, but the main point is that he feels a magmatic eruption -- a bigger one, I think -- could be on the way at any time.

It's a busy day, and I haven't checked X yet, but there is probably more information available on his X feed -- maybe also on Aso"s frequently active Nakadake crater, which is probably going to go off soon. It's not far away and I think they took him up there yesterday, too.

JMA apparently doesn't do stuff like this. 8-O
 
Gonna put this update on a blog post here, under "Volcanoes," just in case. If things go in that direction, it could be big, though possibly just underwater.

Hopefully, it won't need a thread of its own, ever.

July 9, 2025, 11:57 p.m., Pacific: This essay (autotranslated) on the Japanese Research Institute of Marine Geodynamics website, by Dr. Yoshiko Tamura, made me decide to pin this post, although the volcanic process described, if — a big “if” — this is what is causing the swarm, could go on for geological spans of time. Or not.

I had some thoughts along those lines, given the large number of calderas on the seafloor — not to mention the presence of sleeping Kikai, a little closer to Kyushu — but I’m just a layperson.

This is the first commentary by a knowledgeable person that I’ve seen online about the possibility — and that’s all it is, one of several possibilities here which also include a major earthquake or the swarm stopping, as previous swarms here have done.

BTW, “magma fingers” is this researcher’s term and concept of the Tokara region magmatic plumbing. I don’t know that it is in widespread use: there is ongoing debate about the structure and dynamics of volcanic plumbing systems in subduction zones, though not about the basic fact that magma forms here, rises due to buoyancy, and along the way gets more explosive for geochemical and, I think, geophysical reasons.

The papers listed for Dr. Tamura on Google Scholar are highly cited, though.

Also, per this X thread (Japanese) by NHK disaster reporter Shinya Fujishima (which I’m unable to embed), the Tokara Islands of Kohojima and Hojima moved apart almost 10 cm between July 2 and July 5.

That’s way too fast for typical tectonic-generated movements.
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In terms of the other two regional eruption newsmakers, Sakurajima has begun to expand again and is having frequent explosions, while, a few miles to the north, Kirishima/Shinmoedake continues on.

JMA recently announced that some fresh magma has been found in Shinmoedake's tephra. Maybe, considering potential risks and an ongoing controversy, another blog excerpt would be helpful:

July 10, 2025, 12:31 a.m., Pacific: There are no changes noted in updates other than the fact that JMA did not mention the possibility of pyroclastic flows in today’s update.

Earlier updates had noted that flows out to as much as 2 km were possible.

The topic of pyroclastic flows at Kirishima/Shinmoedake has become controversial — and that’s not good when an explosive volcano is erupting in the midst of about 4 million people.

I only know what I’ve read on X (via X translation) by Drs. Hayakawa and Imura, but that’s plenty to go on as both volcanologists are very concerned about pyroclastic flows and believe that mitigation measures should be taken before one reaches inhabited areas.

Dr. Imura got into a public controversy with the local meteorological office over a relatively small cloud a few days ago that spilled over the crater rim and sat there for a while.

He called it a pyroclastic flow even though the local office said it wasn’t going fast enough for one.

This layperson thought it most resembled an electrically charged cloud that Frank Perret described at Vesuvius in 1906. Unlike that one, though, this Shinmoedake cloud did seem to show small coingnimbrite plumes at some of its leading edges in the one cam video I saw of it, which would make that a pyroclastic flow although more views from different angles would have been preferable.

Dr. Hayakawa is as dogmatic as one would expect of an expert who has documented a million years’ worth of tephra in Japan: there have been multiple pyroclastic flows, he says, and the situation is serious.

It is that, for sure, especially with the newly reported detection of fresh magma in Shinmoedake’s ash.

Some say that this is good news because it means that the volcano is degassing and crystallizing its magma — this happens at many quiet volcanoes, of course, but this layperson has not ever understood the process to apply at an actively erupting one.

Fresh magma at shallow levels is probably on the move, and therefore crystallization cannot be the dominant process…at least not until the movement stops and the magma begins to freeze in place.

I don’t know what to think.

Volcanologists should speak publicly with one voice, which Dr. Imura and Dr. Hayakawa are not doing with JMA. At the same time, I’m having Godzilla Minus One Captain Akitsu flashbacks as I contemplate JMA updates, in part while being influenced by Hayakawa and Imura.
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Sigh.

At this point, Godzilla would be a nice distraction. :(
 
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TornadoFan said:
Mt Rainier is having bit of a swarm.
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CVO:

...Currently, there is no indication that the level of earthquake activity is cause for concern, and the alert level and color code for Mount Rainier remain at GREEN / NORMAL.

The Pacific Northwest Seismic Network is in the process of looking at each earthquake and identifying its location, depth and size, if possible. This process is called locating. Some earthquakes are too small to locate. You can follow along in that process and watch the data on their website https://pnsn.org/volcanoes/mount-rainier.

This swarm consists of hundreds of very small earthquakes...
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Currently I'm not in a position to take full advantage of one, but a nice, safe, nondestructive Cascades eruption would be GREAT!

Rainier, though? I don't know. That one doesn't have to erupt to be dangerous.
 
Meanwhile, in Iceland...tension, beauty, and a rainbow over black sand!



Yes, they drive through some rivers there, with the appropriate vehicles (high-bodied, good traction).

There are no major news updates, but what he is referring to as activity possibilities include:

  • The ongoing small (thus far) glacial outburst flood from Katla: Eyjafjallajokull has been shivering a bit, as well. The two often work in tandem.
  • Occasional, moderately strong quakes at Bardarbunga, whose 2014 Holuhraun lava flow was about 1% the size of the Laki/Grimsvotn 1783-1785 flood lava eruption.
  • Occasional seismicity at Askja.
  • Ongoing magma-caused deep seismicity at Ljosufjoll (referred to near video's end, though not by name, where he shows Lake Grojarvatn and says the light wasn't good during his visit there).
He might not be surprised by volcanism occurring on the Reykjanes Peninsula in July, but IMO certainly would be. They issue regular updates, and that sill underneath Svartsengi is slowly refilling, but the next round of activity from it, IMO says, isn't likely until autumn.

Maybe he has Eldey (just offshore) and the Reykjanes fissure system on and off the peninsula's tip in mind? There has been frequent swarming in that general area, though IMO seems to take it all in stride.

I would also add Grimsvotn to a list of potential 2025 activity spots, although it hasn't been quite as restless as its next-door neighbor Bardarbunga.

And Hekla quakes mildly every now and then -- worth noting because it doesn't give much warning before going off, typically starting out in a plinian-style way.

Less likely candidates, but waking up nonetheless, might include Hofsjokull and Oraefajokull (site of the only known high-casualty-count Icelandic eruption, a few centuries ago).
 
Encouraging update on Rainier:

CASCADES VOLCANO OBSERVATORY STATUS REPORT
U.S. Geological Survey
Thursday, July 10, 2025, 9:25 AM PDT (Thursday, July 10, 2025, 16:25 UTC)


MOUNT RAINIER (VNUM #321030)
46°51'11" N 121°45'36" W, Summit Elevation 14409 ft (4392 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN


This is an update on the ongoing seismic swarm at Mount Rainier that began at 1:29 AM PDT (8:29 UTC) on July 8th.

Seismicity is continuing at low rates. As of 9 AM PDT (16:00 UTC) on July 10th, the Cascades Volcano Observatory (CVO) and the Pacific Northwest Seismic Network (PNSN) have located 334 events since the start of the swarm, although many more have occurred but cannot be located. The largest event of the swarm so far was a magnitude 2.3 on July 8th at 2:56 PM PDT (21:56 UTC). Seismicity has decreased from 26 located events per hour at the swarm's peak on Tuesday morning to a few events per hour as of Thursday morning. The earthquakes are mainly spread between 1.5-4 miles (2-6 km) beneath the summit. There have been no changes in ground deformation or other monitoring data.

This swarm now surpasses the 2009 swarm in terms of magnitude, total events, event rate, and energy release. The cause of the swarm remains consist with the circulation of fluids along preexisting faults beneath the volcano, which is considered background activity at Mount Rainier. There is currently no indication that the swarm is associated with magmatic unrest.

PNSN and CVO will continue to monitor activity, locate earthquakes, and provide additional information as needed.

For more information, see: https://www.usgs.gov/observatories/...ect-small-magnitude-earthquakes-mount-rainier
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Kagoshima "Graben of Fire": The only news is that there is no news.

  • Tokara quakes continue, with a recent M4.4 (technically, this region might not be part of the Kagoshima graben per se, but it's in Kagoshima Prefecture). Reportedly (Japanese), geospatial monitoring has increased.
  • JMA notes yesterday that Sakurajima continues to expand. I don't see any VAAC advisories on it since the 12th. This is not necessarily a good thing.
  • Shinmoedake has intermittent small eruptions, including this one a few hours ago:

 
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