Activity at Taal

[MNTornadoGuy]

Taal has been displaying increasing activity recently with very high SO2 emissions (that peaked at 23,576 tons/day on Oct 16), and 1-3 km tall steam plumes. There has been some volcanic tremors and inflation too.
https://www.phivolcs.dost.gov.ph/in...taal-volcano-bulletin-19-october-2021-8-00-am

 

[bjdeming]

Yes, but they're still keeping it at Level 2, just as it has been for months. Hope it stays that way!

 

[bjdeming]

No changes; just thought an update would be good. Volcanic "severe weather," i.e., elevated alert status (when the volcano is known--the most dangerous ones are those that aren't), doesn't pass quickly.

Just for comparison, La Palma's erupting volcano, MUCH smaller, was putting out 50,000 tonnes of sulfur daily at first, and it sometimes gets up in that high end of the range still, though I think the eruption might be winding down.

Gas emissions are a sign there's magma degassing near the surface, but the volume of sulfur, etc., depends mostly on that magma's chemistry. The telltale warning signs of impending trouble are more likely to be ground deformation (Taal is deflating, per PHIVOLCS) and seismicity (high at Taal but within normal limits for Level 2, per PHIVOLCS).

I'm still amazed that so much lake water burbled down into Taal's hydrothermal system after the 2020 blast, yet nothing explosive happened.

BTW, the lake in the nice picture at that link fills most of Taal Caldera; it's huge. The active part right now is the central vent complex called Volcano Island. It used to host one of the very few, perhaps the only, crater lake within a crater lake (the caldera's). Maybe another one has formed.

PHIVOLCS was watching that crater lake on Volcano Island when the January 2020 eruption began:



There's video online that purports to show it, but anything taken with a hand camera close to the lake and showing a plume isn't Taal's 2020 biggy. Both camera and photographer would have probably been vaporized (happened to a couple of hapless volcanologists near the cone of Galeras, Columbia, in 1991).

 

[bjdeming]

Speak of the devil, Taal had a short steam-driven blast Monday night (guess it's Tuesday over there now), per PHIVOLCS.

Also, there were two errors in that last post:

1. Volcano Island began inflating again in August. Level 2 is maintained, though.
2. That tragedy in Colombia happened in 1993, not 1991. I haven't read the book about it in a while and only got back into it today.

 

[bjdeming]

Two more steam-driven small eruptions. Still Level 2.

 

[bjdeming]

Per the Smithsonian's Global Volcanism Program report this week:

PHIVOLCS reported that unrest at Taal continued during 17-23 November. Sulfur dioxide emissions continued to be elevated, averaging 6,643-12,168 tonnes/day. Upwelling hot volcanic fluids were visible in the crater lake, and daily gas-and-steam plumes rose 1-3 km above the lake and drifted WNW, WSW, and SW. Low-level background tremor persisted along with 5-30 volcanic earthquakes per day, 2-4 low-frequency volcanic earthquakes per day, and 1-23 daily episodes of volcanic tremor, each lasting 1-5 minutes. One hybrid earthquake was recorded during 19-20 November and three were detected during 22-23 November. No earthquakes were recorded for a period during 18-19 November. Three short (1-5 minutes) phreatomagmatic bursts were recorded at 0811, 0817, and 0834 on 22 November. The events generated plumes that rose 200-1,500 m based on thermal camera images. PHIVOLCS stated that the events were likely driven by fracturing and gas release from magma beneath the Taal Volcano Island. The Volcano Alert Level remained at a 2 (on a scale of 0-5). PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ) and that boating on Taal Lake was prohibited.

 

[bjdeming]

Taal is having increased degassing this month, with almost 16,000 metric tons of SO2 yesterday and only slightly less today.

AFAIK there are no streaming cams, but here's a shot today of the gas plume rising from the crater lake on Volcano Island, which in turn is surrounded by the crater lake that fills Taal Caldera. (Might want to take some Dramamine before watching.)



Per PHIVOLCS, alert level is still 2 and the edifice continues to deflate.

 

[bjdeming]

Taal had a high SO2 emission for a while and then it dropped by almost half. I wondered if that might mean a blockage in the conduit, and now phreatomagmatic bursts are occurring.

They have raised the alert to 3 (5 is the highest) and ordered evacuations of most vulnerable areas nearby. SO2 in the latest bulletin, while respectable, is still low compared to peak days recently.

I'm so glad this guy is doing daily video. This was posted 8 hours ago:

 

[bjdeming]

A lot of "thousands flee" news stories out there, but it's just phreatomagmatic bursts. There is a magma intrusion reported at the main crater, but per this article PHIVOLCS doesn't see an upgrade to Level 4 coming any time soon.

It isn't mentioned in today's bulletin, but up until now, they have said the deflation that began in October has continued. That's the thing to look for, I think: a switch back to inflation of the edifice would be worrisome.

 

[bjdeming]

Taal has had on and off upticks in activity; I've followed some of it over the summer in a post that's currently pinned at my blog.

But 29 phreatomagmatic bursts, although weak, call for a heads-up.

PHIVOLCS hasn't raised the alert: the other parameters haven't changed with these bursts (it's been at Level 1 for a while, and the present inflation/deflation reported at the above link has been happening for a while, too).

But I learned just how dangerous Taal is, and how quickly its status can change, while revising the DV book (ongoing). This is something to keep an eye on -- things can happen fast here, if the caprock under Volcano Island and atop the hydrothermal system breaks.

 

[bjdeming]

Meanwhile, in Hell at Taal, a YouTuber who is usually sensible and films Volcano Island either from Taal Lake shore or with a drone survived this trip to VI and uploaded the video five hours ago.

It was incredibly stupid (for reasons that the landscape shows), but that little crater lake on VI does look very strange. I've never seen anything like this cottony appearance before.



Per PHIVOLCS, when they last checked the little lake, back in October, its pH was 0.4 and water temps were a balmy 74.3° C.

I wonder what they are today. A civilian could not check, but maybe scientists will have resources enough for them to collect data while the little lake is still cottony.

Taal has been breaking five digits with its sulfur emissions frequently lately, though it was just under that on today's bulletin. Thankfully, atmospheric ventilation of the region is good now...no more inversions.

Again, this was so incredibly stupid a visit -- and so, so interesting.

 

[bjdeming]

Eruption unlikely, per PHIVOLCS, although sulfur emissions are high. Thankfully, regional ventilation is good.

There was one 30-minute tremor reported the other day, and only localized inflation of parts of Taal Volcano Island (TVI) is noted, not of the caldera.

No word yet on why the TVI crater lake looks so cottony, but am guessing that's what some type of sulfuric acid condensate looks like. More video of it was uploaded a few hours ago, not showing any vog despite the 14,000+ tonnes of SO2 emitted Monday, but I'm not going to encourage reckless behavior with a link -- risk is probably a reason why PHIVOLCS hasn't updated the lake data in its bulletins since October

 

[bjdeming]

This is how to do it! (Read the whole thread.) Hopefully, the new data will be included in tomorrow's bulletin.

 

[bjdeming]

Per today's report, that little lake's ph is now 0.2. Of note, 5 is considered acidic. TVI is unlikely to go negative and rival the world-record acid mine waters at -3.6, but it's definitely not something you'd want to touch.

I'd love to know the chemistry behind that cottony condensate just above the water, though.

 

[bjdeming]

A thought from someone who is extremely chemistry-challenged but does know a little about the underground structure.

The cottony condensation is unlikely to contain sulfur since it is white, but the sulfur degassing that acidifies the little lake comes from an underground magma body at some depth (and believed to be more or less centered below TVI).

In between the magma reservoir and TVI is Taal's hydrothermal system, which explodes every now and then, most recently a couple years ago (Taal itself did not contribute much to that drama -- when it goes, it tends to vaporize big Taal Lake and repave what are now three Philippine provinces with pyroclastic ash flows; fortunately, it doesn't cut loose often and shows no sign of doing so in the foreseeable future).

Getting back to the cottony "fog" over little TVI lake, if sulfur is moving through the underground hydrothermal system, so is degassing water vapor from the magma body (plus whatever water vapor it can mobilize from the hydrothermal system).

I don't know how sulfur gases and water vapor interact, especially in various pressure and temperature regimes underground, but that is probably the source of the "cottony" material (perhaps with some contribution from atmospheric humidity) that condenses when it meets relatively cool air above the 70+° C water.

Whatever form of sulfur/magma-conditioned O and H it is must be heavier than the ordinary water vapor that eventually rises and wafts away in the breeze.

 

[bjdeming]

Steam explosion -- "phreatic eruption" -- of the mini-crater lake on Volcano Island out in the middle of the big crater lake filling most of Taal Caldera: PHIVOLCS is keeping the alert level at 1 and notes that a subsequent magmatic eruption is unlikely.

However, magma is down there not too far, as shown by the five-digit SO2 emissions lately. <Layperson speculation>If the caprock over that hydrothermal field under Volcano Island holds, it should be okay.</Layperson speculation>

There's lots of data and video in the thread:

 

[bjdeming]

Marlon Abuyo got a nice video of the backlit plume, uploaded 19 hours ago:



For today's bulletin, Taal's SO2 is back into four digits (barely). Note that overall the caldera has been deflating for a while -- no major eruption seems likely in the foreseeable future.

Smaller-scale eruptions through Taal Volcano Island, like the one a couple of years ago, can be bad, too. One in the 8th century actually cut off the caldera from the sea, and others also have been deadly, mainly because of base surges and tsunamis from that water-magma interaction.

This bulletin notes how TVI is inflating. That is typical; the deformation shifts around, too. I'm not sure how much is due to magma and magmatic fluids/gases and how much to changes in the massive hydrothermal field.

 

[bjdeming]

[PHIVOLCS-DOST on X: "TAAL VOLCANO ADVISORY 16 May 2024 07:00 PM This is a notice of weak phreatic activity at Taal Volcano. https://t.co/2qfNgbJ50b #TaalVolcano https://t.co/E5XkFvWKoo" /

This is the second day of little steam bursts from the crater lake on Volcano Island, but at that linked advisory they say they don't expect evolution into magmatic activity -- alert remains at Level 1.

SO2 emissions are now reportedly averaging four digits -- super-high for most restless volcanoes but down closer to average for Taal.

 

[bjdeming]

No signs reported of impending eruption but Taal is back to five-digit SO2 emission -- and the regional air flow is becoming calm.

 

[bjdeming]

This image is from the PHVOLCS thread: on the left, a station view of Taal degassing; on the right, 16 minutes later, at another station as vog was forming.

Here is a general introduction to volcanic gases from VolFilm: