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Volcano thread

bjdeming

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There's another volcano erupting in the region -- Bagana, on Bougainville island (Ulawun is on New Britain Island).

That's complex, too, but for a different reason: sure, Bagana caused severe enough problems for the government there to ask for help from Papua New Guinea (with whom Bougainville fought a terrible civil war and currently is having tense independence negotiations with), but the world response was IMO out of proportion. Just as one example, we sent in the Marines.

I suspect, as mentioned in that linked blog post/updates page above, that the international response might have more to do with geopolitics, given Bougainville's importance in WWII. But I'm sure not going to speculate on it!

There will be updates there, of course, for any volcano-related info that comes my way. And please, everyone, do share here on the thread, anything you might see on these two or any other volcanoes.
 

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BTW, the volcano over on the other side of town, the one that everyone associates with Naples because of Pompeii, is sound asleep and has been since 1944.

It's thoroughly monitored and they will pick up any signs of reawakening long before Plan Vesuvio is invoked.

Edit: This was posted after I did a post on Campi Flegrei news, and I put it in the wrong thread. Will do one there, too.
 
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bjdeming

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Aaand Kilauea has been rocking again. Reportedly, an eruption might come anywhere between the summit and the December 1974 vents (outside the crater but AFAIK not near any inhabited areas).

I looked up that old eruption and found this (if something similar happens, it could be quite a show, though not as big or destructive as in 2018):



Edit: HVO Kilauea updates page.
 
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bjdeming

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Starting at around -6:19 on this video (live, so time dependent), Sakurajima began venting a little ash, with a little convection to the plume; don't know if this will amount to anything, but again, here are two live webcams:

Crater:



And a bit farther away:



No new JMA update (autotranslated) or change in alert level, as expected because Sakurajima has erupted like this before -- still fun to watch, though.
 

bjdeming

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Zaiho just posted the whole eruption video. It's GORGEOUS!

 

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Sakurajima put some muscle into it this time; 16,000 feet per Tokyo VAAC. This video shows the blast from different angles. No JMA/Kagoshima updates, still Level 3 alert.

 

bjdeming

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Per JMA today (sort of, given time differences):

October 22, 2020 09:00 Announcement by Fukuoka District Meteorological Observatory/Kagoshima Local Meteorological Observatory


<Warning around the crater (volcanic alert level 3, mountain entry restrictions) continues>

 At Sakurajima, crustal deformation indicating the expansion of the mountain body has been observed.

There is a risk of an eruption accompanied by large volcanic blocks or small pyroclastic flows that will be scattered more than 1 km from the Minamidake summit crater and Showa crater. Also, on the leeward side, you need to be careful about ash fall.


Status of volcanic activity​

 At Sakurajima, crustal movements indicating expansion of the mountain body have been observed since around 06:00 yesterday (21st) using inclinometers and extensometers installed on the island.
 
 If an eruption occurs at the Minamidake summit crater or the Showa crater that causes the expansion of the mountain to disappear all at once, there is a possibility that a large amount of ash will fall, mainly within Sakurajima Island. Please use the ashfall forecast issued by the Japan Meteorological Agency for areas where ash and small volcanic blocks are expected to fall.

Disaster prevention precautions, etc.​

 Please be wary of large volcanic blocks and pyroclastic flows that are scattered along trajectories associated with eruptions within a range of approximately 2 km from the Minamidake summit crater and Showa crater.

 Be careful on the leeward side, as not only volcanic ash but also small cinder blocks can be carried far by the wind.

 Please be careful as there is a risk of window glass breaking due to the large air vibrations caused by the explosion. Please note that depending on future ash fall conditions, debris flows may occur during rainfall.

Note that they haven't raised the alert level. I think some explosions over recent years have shattered windows in Kagoshima but generally the five miles or so of bay buffers it.

When I was nerd-watching events leading up to the blast on the 19th, it appeared that emissions were shutting down, then restarting, then shutting, and so forth until enough pressure built up to blow it open (but not enough to maintain a convective column for any length of time).

At the moment, Sakurajima is showing almost no emissions, so...

And night is falling there (the 22nd), so if it goes in the next several hours, we might not see it very well on the cams.

My bad; it's only around 1 p.m. there. Also, in the time it took me to write the above, a fairly respectable column of water vapor appeared. That signifies the vent is more open, releasing some pressure.

When it shuts down, perhaps from sintering with all that moisture, that's when the chances of a blast increase (layperson opinion!).
 
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bjdeming

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No tweets from TROPOMI SO2 regarding an emission; there was such a tweet the day before the October 19th blast. Probably, given the deformation JMA mentioned, it is locked inside right now.

BTW, this is not an urgent situation (for anyone not on the island) Yes, it could blow any moment, or several hours from now, or tomorrow, or...

It would be so much easier if they could directly see inside these things.

As mentioned somewhere up above, Sakurajima's plinian blasts tend to come from flank fissures as in 1914. JMA hasn't reported any thermal anomalies other than one in between the two summit craters.
 
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bjdeming

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There is a fair amount of water vapor (and minute quantities of ash) coming out. This could take a while. Here is the Tokyo VAAC link.

Also, how to read an advisory.
 
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bjdeming

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The nice (?) thing about weather is that you can estimate when the bad stuff will arrive.

Still waiting on Sakurajima. Of course, this long a delay in eruptions could mean it was settling down, but the water vapor coming out of Minimadake (left, on Cam C, with Showa, I think, on right) when I watched yesterday during daylight up through about 0830 UTC was very hot (entraining lots of air to build convective clouds) and at times seemed to fountain more than just come out, indicating pressure behind it. Also, some ash is continually leaking out with the water vapor (meaning there's lots more where that comes from).

There's heat and pressure and magma in there, very close to the surface, and again, what emissions do happen seem to follow that "more open-more closed" pattern I noted on the 19th.

It's not going to settle down, unless this goes on for a verrry long time, slowly reducing pressure and cooling off the magma (not something Sakurajima, a vent of Aira Caldera, tends to do).

That would actually be bad, putting a plug of hardened magma in a normally open conduit. Very bad.

But it's not likely to happen.

Layperson speculation, but I think Sakurajima's usually open conduit recently clogged up a little and the volcano needs to clear its throat, and, hopefully, eventually will via the superficial magma system and the summit vents (existing and/or new ones).
 

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Not even Volcano Discovery seems to have a live feed of webicorders, and I've never yet been able to thoroughly negotiate JMA's website, partly because of the language barrier, and perhaps also partly because of cultural differences regarding the handling of information. I don't understand the Japanese very well (and am not alone in this).

Anyway, if you're looking at Cam B, that cloud on the lower right flank right now is definitely weather.

And I thought emergency management folks here might enjoy reading this paper by three USGS/VDAP veterans of Mt. St. Helens (1980), Pinatubo (1991), Merapi (2010) and probably much more: https://www.researchgate.net/public...risis_operations_within_volcano_observatories

This layperson doesn't expect Sakurajima now to do something that would approach those intense events (JMA probably would pick it up and raise the alert level) -- it's more just general info on crisis handling from a discipline other than meteorology.
 

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Updates are daily at the moment, instead of every three days or so.
JMA/Kagoshima Observatory uses the same wording today. Tokyo VAAC reported a couple of small explosions up to 15,000 feet, and the volcanologists counted several small ones.

I noticed a tiny one on the cam yesterday at around 11:30 a.m., local time.

There is still the possibility of a big one (though not outside Level 3 alert guidelines, apparently).
 

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Over the last 2-1/2 hours, the summit has popped three times: once on the left (Cam C), which I think is the Minamidake area, shortly after 8 a.m. local time; twice from the general righthand area (Cam C), where Showa is, I think.

Judging by the sequence, small intensity, and the immediate enhancement of that condensation cloud over the summit, I'd guess, as a layperson, that the hydrothermal system exploded -- not anything new, but an interesting left-to-right sequence over two hours.

Emissions are returning now on the Cam-C right, but the left has been without sign of activity since the first explosion around 8:08 a.m., local time.

Because of that and the way big fishing boats have disappeared from the bay in mid-morning, I figured it was worth an update.

Just in case it develops, again here are the cams I'm watching:







As you can see on A, Sakurajima has been leaking ash all day, consistently but in very small quantities and very wet.

These explosions weren't anything like as magmatic as the explosion on the 19th, but it remains to be seen what will happen next.
 

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Went back to the cam and noticed more big fishing boats out there -- my guess is that they might have gotten word of increased seismicity from the observatory after that first explosion and cleared out; the second set of explosions happened, and now the word perhaps is that this particular crisis is over.

Good, if so. Anyway, there are the cams all together.
 

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Zaiho just released a short video of one of last night's explosions (local time). That humid ash produced incredible volcanic lightning!



As for Sakurajima currently, it seems to have settled back into the degassing routine -- except for the left (Cam C), which up until today after 8:08 or so used to degas, too. So far now, nothing.
 

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That bad boy apparently released the pressure per the current update fron JMA (via Google Translate):

Status of volcanic activity​

 Inclinometers and extensometers installed on Sakurajima Island had been observing crustal deformation indicating the expansion of the mountain since around 06:00 on the 21st, but an eruption occurred at the Minamidake summit crater from 03:46 today (24th). It was resolved by.
 
 This eruption continued until around 04:30, and the volcanic smoke rose 3,400 meters above the crater rim. The large volcanic blocks scattering in a trajectory reached as far as the 5th station (approximately 1200m from the Minamidake summit crater).
 
 At Sakurajima, magma has accumulated for a long time deep underground in the Aira Caldera (inner part of Kagoshima Bay), and the amount of volcanic gas (sulfur dioxide) released is generally large, so the Minamidake summit crater and the Showa crater Eruptive activity is expected to continue in the future. Please pay attention to future volcano information.
 

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Sakurajima apparently didn't read the update. =8-0
 

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Still phreatomagmatic, I think (steam-magma) I hope it stops soon.

Edit: Plume only 15,000 feet per Tokyo VAAC.
 
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bjdeming

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The thing to remember with this complex plumbing, I guess, is that Sakurajima edifice is not the whole volcano. It's just a vent, with the ultimate magma supply deeper and under northern Kagoshima Bay.

Not that this is tapping that (layperson opinion): that would really push up a plume! My guess is that this is more of the hydrothermal system busting loose.

And hopefully it's over now.
 
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