Mount Agung volcano

[Windspeed]

Is it possible that the longer this activity continues, the more pressure builds up leading to a bigger eruption?

As long as magma continues to enter or re-energize within the edifice, certainly. Seismicity is important in that respect, as it can still show rising magma at depth. However, if that slows over a period of time, it could also degass without eruption and decrease in explosive potential. CO2 degasses faster than SO2 from depth. However, if SO2 starts increasing at the surface, it could mean magma is in closer promixity to the surface with risk of explosive eruption or it could mean magma is degassing fast enough that the eruption is less explosive -- resulting in a new lava dome building phase ensuing. The problem is we cannot see what's going on inside the volcano. We can only sample and measure what's coming out of the summit remotely. It's dangerous to try and land and fly vehicles inside the crater with such high levels of seismicity. An eruptive event could occur any moment and it is a big risk. It would be awesome if we could get a drone down in there to sample CO2 & SO2 right now.

 

[raindancewx]

At this point I hope it doesn't fizzle out - it really hurts the cred of the authorities telling people to leave if it doesn't erupt. It's worse than a hurricane warning where the storm weakens or changes direction last second because people don't have tools to track the event themselves.

In an ONI sense, 1932-33 was a cold Neutral (-0.2C) if you use the data Phil Klotzbach posted a while ago, but in a raw SST sense, 1932-33 has been within 0.2C of now for most of the year, as even slightly negative departures back then look La Nina-ish now by raw SSTs. The event was two years after a big El Nino (1930-31), and 1931-32 was a similar super hot SE / cold winter West. Even with the hurricane similarity, PDO/AMO/Solar similarities I'm not using 1932-33 as a top analog for the winter unless we get a big eruption in the next two weeks since it had the VEI 6. Earlier in the year, the whole ONI warming from winter to Summer, and then cooling from Summer to Fall (and probably winter) made me think this winter would be like either 1963 or 1932, and BOTH had big volcanic eruptions.

 

[Windspeed]

At this point I hope it doesn't fizzle out - it really hurts the cred of the authorities telling people to leave if it doesn't erupt. It's worse than a hurricane warning where the storm weakens or changes direction last second because people don't have tools to track the event themselves.

In an ONI sense, 1932-33 was a cold Neutral (-0.2C) if you use the data Phil Klotzbach posted a while ago, but in a raw SST sense, 1932-33 has been within 0.2C of now for most of the year, as even slightly negative departures back then look La Nina-ish now by raw SSTs. The event was two years after a big El Nino (1930-31), and 1931-32 was a similar super hot SE / cold winter West. Even with the hurricane similarity, PDO/AMO/Solar similarities I'm not using 1932-33 as a top analog for the winter unless we get a big eruption in the next two weeks since it had the VEI 6. Earlier in the year, the whole ONI warming from winter to Summer, and then cooling from Summer to Fall (and probably winter) made me think this winter would be like either 1963 or 1932, and BOTH had big volcanic eruptions.

Let's say hypothetical Agung goes bonkers and has a VEI 5 or 6 event with high volumes of SO2 released. There will still be some lag time with tropical tropospheric cooling. It may begin to affect late Winter / early Spring 2018. I suspect the bigger effects would proceed with greater influence into next Fall and Winter.

 

[Windspeed]

[Windspeed]

[SnowLover22]

“

Mount Agung has started to inflate or swell, according to the latest tiltmeter data.

The findings suggest that the volcano is filling with magma and experts now believe an eruption is the most likely outcome for Mount Agung.”

Richard Arculus, former professor of geology at Australian National University, told the Wall Street Journal: “It’s much more likely to keep going now then to stop.”

[Vice-Regent]

19 hours ago, goldsborosnow said:

Is it possible that the longer this activity continues, the more pressure builds up leading to a bigger eruption?

Quite the opposite, pressure is being released as time goes on.

[WhiteoutWX]

19 hours ago, Windspeed said:

Let's say hypothetical Agung goes bonkers and has a VEI 5 or 6 event with high volumes of SO2 released. There will still be some lag time with tropical tropospheric cooling. It may begin to affect late Winter / early Spring 2018. I suspect the bigger effects would proceed with greater influence into next Fall and Winter.

 

Do these things really take that long to have an effect on climate? I would have thought that it would bring effecting it as soon as the volcanic aerosols are advected globally and can begin blocking incoming solar radiation, like within a couple weeks of eruption. I lack any expertise in this area of meteorology but just from my basic understanding of aerosols I would have expected a more immediate impact.

[Windspeed]

Quite the opposite, pressure is being released as time goes on.

 

Pressure is being released as time goes on is not always an indicator of what is occurring though. We need to be careful. If the injection from depth ceases and the shallow magma is able to degass faster than it can reach atmospheric pressure, then certainly, the eruption would result in a less explosive dome/cone building phase. But how much time are we talking here? A few months isn't enough to decrease the threat of explositivity. We also need the number of deeper earthquakes to subside to show that perhaps deeper injection has slowed. The real answer to the original poster's question is dependant on evidence we have not yet ascertained. That can only be answered truthfully when the eruption begins and we sample the lava.

 

Typically, yes, rising magma will begin releasing trapped CO2 at depth and SO2 at shallower layers as the surrounding pressure decreases. It will inevitably become less explosive given time and proximity to the surface. But we have no idea just how much new magma is being injected into the chamber, felsic material mixed and gases trapped until the initial eruption ensues. We need deeper injection to slow or cease, then yes, time can be our friend.

 

There is also another type of eruption versus Agung's more recent episodes we could entertain, though certainly far more unlikely. We do occasionally get less evolved mafic eruptions. In this case, the new basalt injection or dyke(s) does not disturb the crystal mush held in stasis in the chamber or misses crystallization altogether, reaching the shallow layer much faster producing a basalt eruption instead of andesite or dacite. We've had evidence of this occurring at plenty of even more felsic stratovolcanoes like Mt. St. Helens in the Cascades and other cones in Indonesia when studying their older eruptive history. This would be great as basalt has less viscosity, degasses more rapidly and lends to far less explositivity. But this is just a screwball to throw out there and far more unlikely/rare. In any event, Agung's recent geologic eruptive history has been dominated by andesite/dacite lavas, tephra and dome growth. Based on this, more evolved mafic to intermediate lavas with higher silica content and explosive potential, Agung will most likely produce.

 

Edited to show Agung's more evolved mafic-to-intermediate lavas based on publications and recent geologic eruptive history thanks to the link by ma blizzard.

 

[Windspeed]

Do these things really take that long to have an effect on climate? I would have thought that it would bring effecting it as soon as the volcanic aerosols are advected globally and can begin blocking incoming solar radiation, like within a couple weeks of eruption. I lack any expertise in this area of meteorology but just from my basic understanding of aerosols I would have expected a more immediate impact.

Define immediate? With respect to climate, a 0.5°C or greater drop in tropospheric mean over a year is rapid. But I understand your question. The answer is yes, they do take some time. Most of your heat content is stored in the oceans, not the atmosphere. Water is a much better medium for heat content storage. It takes time to decrease shallow and deep layer heat stored up that helps moderate air temperature. Since the bulk of tropical surface area is covered by water, the amount of declining incoming solar radiation or insolation won't decline fast enough to decrease tropospheric warming in the matter of a few weeks. It takes many months.

 

Now that I explained this, please keep in mind that it also takes time for aerosols like SO2 and particulates to spread evenly throughout the stratosphere to decrease insolation. Obviously, the larger the eruption and greater the amount of aersols/particulates blasted into the stratosphere, the faster and greater the drop in insolation may occur. Tambora is a good example of a global cooling event. Toba is an extreme example (one we don't want to experience). But we didn't have remote sensors around back then to measure just how rapidly insolation decreased over time from the eruption event. We do have good records for Agung's 1963 eruption and terrific records for Pinatobu 1991, and both cooling events still took the better part of a year to reach coolest mean.

[ma blizzard]

a good resource: https://www.researchgate.net/publication/279225389_A_5000-year_record_of_multiple_highly_explosive_mafic_eruptions_from_Gunung_Agung_Bali_Indonesia_implications_for_eruption_frequency_and_volcanic_hazards

[Windspeed]

a good resource: https://www.researchgate.net/publication/279225389_A_5000-year_record_of_multiple_highly_explosive_mafic_eruptions_from_Gunung_Agung_Bali_Indonesia_implications_for_eruption_frequency_and_volcanic_hazards

This is also a good page/write up for the quicker historic geological sense for Bali's volcanoes.

http://www.volcanocafe.org/romantic-paradise-destination-the-new-decade-volcano-program-6-bali/

[Windspeed]

Indonesia's Centre for Volcanology and Geological Hazard Mitigation (CVGHM) is now publishing their updates in English as well:

 

https://magma.vsi.esdm.go.id/press/view.php?id=98

 

The page is slow to load so I'll just quote the most recent update here:

 

Recent Updates on Mount Agung Volcanic Activity (per September 29, 2017)

 

29 September 2017 11:18 WIB, Ir. Kasbani, M.Sc.

 

A. Volcano Monitoring Data:

 

Seismic:

 

Recorded volcanic earthquakes still show high numbers. These earthquakes indicate brittle failure inside the volcano caused by magma movement.Calculated magnitudes of earthquakes have continued to increase. Magnitude of the largest volcanic earthquake during the crisis period is M4.3 on September 27, 2017 at 13:12 Central Indonesian Time (UTC+8) and more earthquakes are being felt recently by people around Agung and Batur areas, and some of the biggest earthquakes are even felt in Denpasar and Kuta areas.Volcanic earthquakes are estimated to be located within 20 km of the volcano's summit.

 

Satellite remote sensing :

 

Satellites have detected new steam emissions and thermal areas within the summit crater; these areas have expanded during the past week and now include a new area of emissions in the center of the crater.

 

Visual observations:

 

White steam clouds are occasionally observed rising 50-200 m above the summit; and currently, the emissions activity are observed to be more frequent.After a M4.2 earthquake on September 26, 2017 at 16:27 Central Indonesian Time (UTC+8), a larger white steam cloud was emitted to a height of around 500 m above the summit.

 

Deformation:

 

Analysis of tiltmeter data suggests some inflation (swelling) of Mount Agung.

 

 

B. Analysis:

 

Based on the analysis of current monitoring data, at this moment, the probability of an eruption is higher than the probability of no eruption; however, the probability may change at any time depending on current monitoring data.If an eruption does occur, it is most likely to be small at first; however, a large eruption may follow. The size of future eruptions cannot be determined with certainty.The exact date and time of future eruptions cannot be predicted, however; CVGHM will issue warnings when conditions change and eruptions are more certain.It is still safe to travel to Bali; however, visitors should not enter the restricted areas near the volcano (currently at distances of 12 km to the southeast to southwest and north to northeast and 9 km elsewhere. CVGHM has worked with the Indonesian National Agency for Disaster Management (BNPB) to develop warnings for eruptive activity.Visitors to Bali and local people should stay aware of hazard warnings from Indonesian government officials. Current information can be obtained via CVGHM's web and mobile phone application Magma Indonesia (magma.vsi.esdm.go.id) and via Google Playstore.

 

Kasbani,

Head of CVGHM, Geological Agency

Ministry of Energy and Mineral Resources

[LithiaWx]

Windspeed, what is your background?  You seem to be very knowledgeable about volcanos and hurricanes.  Your input in this thread is appreciated. 

[Windspeed]

Windspeed, what is your background?  You seem to be very knowledgeable about volcanos and hurricanes.  Your input in this thread is appreciated.

 

I majored in Geology and Geography in college and worked in GIS for years. No graduate level degree but I am an enthusiast on natural extremes and have been fascinated with tropical weather, earth science and climate for most of my life. I assisted in teaching the tropical weather / cyclones portion of a meteorology class for a few years. I also still read as much as I can. I've thought about returning to college for graduate studies to teach but that whole living thing gets in the way. I still may... But I enjoy discussing and sharing what I know on here when I can.

 

Also thanks for the appreciation. There are a tremendous amount on knowledgeable professionals in science and meteorology that post on the AmericanWx forums. I would not consider myself a professional, just an enthusiast.

 

[Windspeed]

An excellent paper on the petrology and emissions of the 1963 eruption:

Abstract - The 1963 eruption of Gunung Agung produced 0.95 km3 dense rock equivalent (DRE) of olivine±hornblende-bearing, weakly phyric, basaltic andesite tephra and lava. Evidence for magma mixing in the eruptive products includes whole-rock compatible and incompatible trace element trends, reverse and complex compositional zoning of mineral phases, disequilibrium mineral assemblages, sieve-textured plagioclase phenocrysts, and augite rims on reversely zoned orthopyroxene. Basalt magma mixed with pre-existing andesite magma shortly before eruption to yield basaltic andesite with a temperature of 1040–1100  °C at an assumed pressure of 2 kb, f O2>NNO, and an average melt volatile content (H2O±CO2) of 4.3 wt.%. Magma-mixing end members may have provided some of the S and Cl emitted in the eruption. Glass inclusions in phenocrysts contain an average of 650 ppm S and 3130 ppm Cl as compared with 70 ppm and 2220 ppm, respectively, in the matrix glass. Maximum S and Cl contents of glass inclusions approach 1800 and 5000 ppm, respectively. Application of the petrologic method to products of the 1963 eruption for estimating volatile release yields of 2.5×1012 g (Mt) of SO2 and 3.4 Mt of Cl released from the 0.65 km3 of juvenile tephra which contributed to stratospheric injection of H2SO4 aerosols on 17 March and 16 May, when eruption column heights exceeded 20 km above sea level. An independent estimate of SO2 release from atmospheric aerosol loading (11–12 Mt) suggests that approximately 7 Mt of SO2 was injected into the stratosphere. The difference between the two estimates can be most readily accounted for by the partitioning of S, as well as some Cl, from the magma into a water-rich vapor phase which was released upon eruption. For other recent high-S-release eruptions of more evolved and oxidized magmas (El Chichón, Pinatubo), the petrologic method gives values two orders of magnitude less than independent estimates of SO2 emissions. Results from this study of the Agung 1963 magma and its volatile emissions, and from related studies on eruptions of more mafic magmas, suggest that SO2 emissions from eruptions of higher-S-solubility magma may be more reliably estimated by the petrologic method than may those from more-evolved magma eruptions.

Petrology and sulfur and chlorine emissions of the 1963 eruption of Gunung Agung, Bali, Indonesia - https://link.springer.com/article/10.1007/s004450050139

[Maestrobjwa]

 Who did this?? Hahaha

[Windspeed]

 Who did this?? Hahaha

Lol that's not even Mount Agung. I think that's Batur. But funny nonetheless.

[Maestrobjwa]

3 hours ago, Windspeed said:

5 hours ago, Maestrobjwa said:

 Who did this?? Hahaha


 

Lol that's not even Mount Agung. I think that's Batur. But funny nonetheless.

Yeah I saw that when someone posted a response (forgot to mention the error here!). But yes...still funny, lol

[Windspeed]

[Windspeed]

Agung is still rocking and rolling. Last 24 hours has inceased to previous highest levels of seismicity. Still no sign of an eruption but clearly fracturing and hydrothermal interaction with rising magma continues.

 

[Windspeed]

Agung is still going strong on the seismic front. Agung is currently experiencing unprecedented levels as far as live seismic monitoring of a reactivating volcano in Indonesia. We have seen this before in the Philippines with Mount Mayon and several other volcanoes in the Andes, but this is quite a lot of prolonged hydrothermal fracturing and magmatic intrusion into the edifice. Obviously, nobody knows if Agung will erupt; but at this point, it would be surprising for nothing to occur than hyperactive fumaroles in the summit crater.

 

[raindancewx]

I'm on board with the quote from the older folks from above - think it will erupt but may be a while yet, months possibly.

[Windspeed]

I'm on board with the quote from the older folks from above - think it will erupt but may be a while yet, months possibly.

I don't think it will be months. I'm more inclined to think Bali is within weeks of an eruption. I am not a volcanologist to make that call though and we do not yet have any type B LPEs (Long Period Events) on the seismograph. Everything so far has been type A hydrothermal, rock fracturing and tectonic signatures. However, it is the frequency and magnitude of these type A events that are concerning. Inevidably, more prolonged events that show actual liquid rock/dyke intrusive behavior are what we're looking for in the near surface strata, but those could happen at any moment.

[Maestrobjwa]

10 minutes ago, Windspeed said:

I don't think it will be months. I'm more inclined to think Bali is within weeks of an eruption. I am not a volcanologist to make that call though and we do not yet have any type B LPEs (Long Period Events) on the seismograph. Everything so far has been type A hydrothermal, rock fracturing and tectonic signatures. However, it is the frequency and magnitude of these type A events that are concerning. Inevidably, more prolonged events that show actual liquid rock/dyke intrusive behavior are what we're looking for in the near surface strata, but those could happen at any moment.

So would those "LPEs" be like last-minute warnings? (Or is there any such thing as "last minute warnings" when it comes to eruptions? Lol)

[Windspeed]

So would those "LPEs" be like last-minute warnings? (Or is there any such thing as "last minute warnings" when it comes to eruptions? Lol)

 

Yes, when you start seeing an LPE on the seismograph, then you can start worrying about imminent eruption. Unfortunately, this is still full of uncertainty and the problem is this can be as little as a few minutes to a few hours. There is not a practical lead time with these imminent eruption type B signatures for warning the public, which is why they are impractical for warning. The type A events that are ongoing are ample enough lead time for warning. With respect to seismology, you are not waiting on LPEs to warn the public. At that point, you're in trouble.

 

Edit: Let me just be clear about this, we do not have the ability to ever show imminent eruption in a practical sense. Anyone that says that an eruption is "imminent" is spewing BS. We have made amazing advancements in seismology, but trying to gauge an eruption upon them is dangerous and ill-advised. All we can do is register the signatures that are clearly magmatic intrusion and process that flash ground water to steam. We are seeing that at unprecendented levels at Agung due to it being such a studied volcano (the 1963 event), and enough of monitoring stations are around the area of the volcano because of its history. We are seeing all these deep signals, shallow rock fracturing and water-related vaporizing expansion that screams magma is rising into the cone's edifice. But we cannot yet pinpoint or determine accurately when the eruption will occur. The reason I mentioned LPEs above is that when you see them, you know dyke(s) have begun to push rapidly through near-shallow stratum. That means the seismic signature is such that an eruption is about to occur or underway. But you cannot wait on these signatures for practical warning of the public. At that point it may be too late.

[Drz1111]

Also, Agung is a bit of a funny volcano - it has a history of starting small and then building to a big eruption.  Eruptive episodes are pretty long.  And it's last eruption is far enough back that it predates all the modern work on harmonics and stuff so it's not like they have an analog to compare it to.

[Drz1111]

Also, generally you'd also look for increased outgassing of SO2 as a sign things are getting close to popping.  But on a highly active hydrologic environment like Agung, you might have ground water scrubbing the SO2 (and the steam is pretty much telling you that ground water is interacting with magma at depth, or at least with increased heat flux).

[Windspeed]

I will say this, it is good that the Indonesian government has amplified efforts to keep people away. Especially anyone climbing the peak. With all the science involved, this is about as clear-case as it gets that this volcano is going to erupt. Nobody should be anywhere near the cone or inside the exclusion zone with all the data that is being observed.

[Windspeed]