Volcano thread

[bjdeming]

There's a lot of excitement online -- undocumented and AFAIK unjustified, at least on YouTube -- about Askja possibly about to erupt, up in Iceland. But there's also a volcanologist up there talking to media about it.

Could be interesting, but it's complex. I did a post on it, with links, etc., for further information.

In the meantime, check the source of whatever you might hear, and if it seems reliable, please do share it here. Askja last erupted in 1961, and per the Smithsonian GVP, most of its eruptions have been in the VEI 0-2 range, but it did have a VEI 5 in the 19th century and a VEI 6 back a few thousand years BC.

And apparently there is quite a bit of magma down there now but no one is certain yet what it's going to do, if anything (or in that one volcanologist's case, when it will get active).

 

[bjdeming]

There has been a dramatic-appearing pyroclastic flow at Mount Merapi, on the island of Java in Indonesia.



This is part of an eruption that has been ongoing since 2020.

Volcanologists, AFAIK, didn't raise the level, which is already next to highest. They didn't call for evacuations, either (as of when the Jakarta Post interviewed them, anyway), even though a little over a million people live on this Decade Volcano. Several million more live at its feet.

Just a guess: One or both of its summit lava domes blew. Will see what the boffins say in the coming week.

Merapi is an interesting/challenging volcano to monitor. I posted the current revision of its Decade Volcano eBook chapter, if anyone's curious -- still working on that.

 

[bjdeming]

It's ongoing, but these flows are only going out a kilometer or two -- I'm no Merapi expert, but I'm pretty sure that's "just" a dome-collapse flow without a lot of explosive power behind it, which would send the flows out maybe 6 km or more.

That's evacuation time, per the Jakarta Post article.

There was a respectable vertical cloud at first, judging from images in the media. It could be that much or all of the southwest lava dome has failed (as summit domes here almost always do eventually).

These flows are going down the uninhabited part of the southwest flank, where flows often went until the turn of this century (depending on the source, it was either in 1994 or 2006 that the flows went more southward -- towards more densely inhabited areas, and ultimately Yogyakarta some 19 miles away).

This is getting a lot of media coverage, which is fine, but just to stress an important point: it's not another 2010 VEI 4.

The GVP currently lists it as a VEI 1.

Given the way Merapi has stayed rather low-key since starting up in 2020, perhaps it will stay in the typical VEI 1-2 range, but the most recent eruption was a VEI 3, which is less common but not unheard of.

In the 20th century, it went decades between those moderate eruptions, but some experts say the volcano's behavior in that century was quieter than earlier times. So maybe this might develop a little more intensity.

We'll see. They do note that the pattern of one or two big ones (subplinian VEI 4) per century holds up on average.

 

[bjdeming]

Here's an official live stream (sorry about the electronic whistle):

Merapi Activity Live Streaming

Pantauan seismik dan visual Gunung Merapi. Data yang ditampilkan merupakan data mentah dari stasiun pemantauan Gunung Merapi. Data memerlukan pengolahan, ana...

www.youtube.com

 

[bjdeming]

Here's part of the March 12th update via Google Translate (note: it translated "lahar" as lava, but they mean a volcanic mudflow, NOT lava, which is too sticky to get far out of the summit crater):

RECOMMENDATION
1. The current hazard potential is in the form of lava avalanches and hot clouds in the south-southwest sector including the Boyong River for a maximum distance of 5 km, the Bedog River, Krasak, Bebeng for a maximum of 7 km. In the southeastern sector it includes the Woro River for a maximum of 3 km and the Gendol River for 5 km. While the ejection of volcanic material in the event of an explosive eruption can reach a radius of 3 km from the summit.
2. Communities not to carry out any activities in potential hazard areas.
3. The public should anticipate disturbances caused by volcanic ash from the eruption of Mount Merapi and be aware of the dangers of (lahar), especially when it rains around Mount Merapi.
4. If there is a significant change in activity, then the activity status of Mount Merapi will be reviewed immediately.

 

[thundersnow]

Swarm of quakes at Alaska volcano could mean eruption coming

ANCHORAGE, Alaska (AP) — A swarm of earthquakes occurring over the past few weeks has intensified at a remote Alaska volcano dormant for over a century, a possible indication of an impending eruption.

apnews.com

 

[bjdeming]

Here are the AVO activity pages for Tanaga and Takawhanga. Both are still Orange status as of current update, March 12th.

 

[bjdeming]

Merapi: Yep, it's a coulee.



Official status is unchanged; it looks to this layperson like the lava dome at the top of the southwestern flank blew, and now the volcano is growing another one.

Lahars from all that ash will be the main problem here, I think.

Survey Results of the Geological Agency Drone Team After the Awanpanas Drop Incident on 11-12 March 2023 On March 11-12 2023, Mount Merapi launched a hot cloud towards Kali Bebeng. Until now, Monday, March 13 2023, there have been 60 incidents of hot clouds falling on Mount Merapi.

Also, there is a second dome (well, likely the only one just now) in the summit -- something to also watch, though even if it blows, too, that would be well within the "typical" range of Merapi's behavior. Flows from that would tend to head down the south flank. Both that and yesterday's west/southwest field are known hazard areas and no one has settled in this "Forbidden Zone" -- people do work there illegally, and hundreds of thousands live right outside the zone; all of these people are at risk from surges, channel-jumping, and other atypical behavior, but as far as I know, there were no human casualties.

 

[bjdeming]

The difference in scale here:

Ash removal, Merapi 2023 (VEI 1):



Merapi, 2010 (VEI 4):

 

[bjdeming]

Getting lost in interesting but not ongoing-eruption-related volcano Twitter today.

Just a couple of especially notable things:

1. Missed this yesterday: the start of Vesuvius' last eruption, 79 years ago. Nice pictures; Tweet thread is in Italian but Twitter can translate it (or your own machine translator).

The volcano is still quiet, and boffins aren't sure if it has begun one of its centuries-long sleeps -- in 79 AD, the Romans didn't even know it was active (this unrelated video checks out with an open-access article I read; PDF download is free) --



-- or if today Vesuvius is just messin' with us. Four decades is an unusually long break, at least during historic times; we'll see. (PS: As explained in that paper, and suggested also by the Smithsonian GVP, the Pompeii eruption actually might have started October 24, but either way, it was bad, and not just for Pompeii.)

2. New Zealand is rocking. Lots of good info and background at link.



Taupo is just off the lower left corner; no news there, still Level 1 alert.

Unlike Yellowstone -- a hotspot volcano -- Taupo is in a subduction zone and actually is only a part of the Taupo Volcanic Zone (this link also connects you with GNS Science, mentioned in the article linked in that tweet above).

It's the TVZ that's rocking the most -- not for the first time, either, per that article.

 

[bjdeming]

Meanwhile at Merapi...

 

[bjdeming]

From this article:

Hundreds of tremors have been occurring over the last few days, with the largest a 4.8 magnitude.

Some Kawerau businesses had to shut down with stock repeatedly thrown from shelves, and some people decided to leave for a few days until the shaking stops.

A crack may have formed in the side of nearby Mt Putauaki, a dormant volcano on the edge of the Taupō Volcanic Zone.

Not all of the quakes GeoNet tweets are from this swarm, but many are. It really must be nerve-wracking.

If it is related to volcanism, there's quite a number to choose from here -- haven't selected any, other than Taupo, for my blog because it is a very complex zone.

Dr. Wikipedia notes that Mount Putauaki is part of the impressive Okataina complex and is also called Mount Edgecumbe (just to mess with our minds even more, Alaska has a restless Mount Edgecumbe, too, though I'm not sure spelling is the same despite my doing so here -- it's been a long day ).

This may just go on for a while and then settle down, as multiple previous swarms have done, but there is so much geological stuff going on here, it's worth watching.

 

[bjdeming]

After learning that Mount Aso in Japan went off yesterday in spectacular fashion

An interesting geothermal energy/seismicity paper, focused on that volcano, just dropped; it also mentions the 2021 blast, which apparently was a good thing for energy production (besides looking GREAT and scaring the bejabbers out of everyone).

Dynamics between earthquakes, volcanic eruptions, and geothermal energy exploitation in Japan - Scientific Reports

Intruding magma brings high temperatures close to the surface, thus offering possibilities for harnessing large amounts of heat for geothermal exploitation. Mount Aso in southern Japan showed frequent volcanic activity during 2016, accompanied by significant earthquake activities with tens of...

www.nature.com

 

[bjdeming]

New Zealand quakes:

While a decreasing earthquake count is being observed and a continuing downward trend remains the most likely scenario, GNS Seismic Duty Officer, John Ristau cautions any premature celebrations.

“We expect an overall decrease in frequency of these earthquakes over time, but we have no way of knowing that for sure,” John says.

“As scientists and earthquake experts, it is natural for people to expect we have all the answers – but the reality is, no one in the world can predict earthquakes – we can only forecast them. We think this swarm will dissipate and we are currently seeing evidence of that, but we could still see that change.”

“We recognise it is disconcerting, but our best professional advice is to always be prepared, and use this time to ensure your whanāu, and your home and workplace is earthquake-ready.”

-- GeoNet