Kilauea Volcano is spectacular today.

Hans Blaster said:

A new episode is brewing and is in the preliminary phases. That could last a few hours or a couple days and then go off... Stay tuned.

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Low level fountains active, full fountains should build shortly from here.

Episode 28 started in the pre-dawn hours of (Wed) July 9 and ended in the early afternoon of the same day.

This last episode was much like the last few. Most outflow came in a period of fountains reaching up to 365 m. (From the opening of the vent, I assume, but they haven't said so explicitly.) There seems to be less flow away from the vents and more accumulation near the vents. Speaking of vents, after only weak eruption from the south vent in the last episode, there was none here this time and the lava seems to have buried the south vent. We may not see activity from the second vent again unless something else changes (like both vents becoming covered).

Some photos of the eruption and the geologists exploring it, including a visit during the eruption inside the 2018 caldera to obtain samples.

Photo & Video Chronology — July 9, 2025 — Kīlauea Episode 28

Now for a touch of speculation...

The vent is building a wide cone structure, a small shield perhaps. Some of the lava is ending small and cooled enough to land as loose, light, small rocks (tephra). Some of this falls above the rim and is making a large, thick field of crunchy rocks. (Lots of good shots in the above link and others like it.) When the same comes down with some hotter blobs it forms a thicker, cooler flow that doesn't spread as easily and becomes thicker. This structure that is building is not in a flat place, but starts right from the edge of the crater with the steep wall adjacent to it.

In the photo below, the vent is "smoking" in the lower left with the lava accumulated from the recent episodes perched above it. It has been slumping down slope, but it has largely flown around the sides (it was all smooth when the episode ended). Some stuff has certainly fallen down the vent, but if in aftermath of an upcoming episode a large amount collapsed on to the vent, it could have a major impact on this eruption. Stay tuned.

If it's chucking relatively heavy lava a thousand feet up then presumably the ash is going a lot higher. I'm surprised I can't find any flight restrictions online?
Sounds like it's almost inviting another Speedbird 9 incident.

MyOwnSockPuppet said:

If it's chucking relatively heavy lava a thousand feet up then presumably the ash is going a lot higher. I'm surprised I can't find any flight restrictions online?
Sounds like it's almost inviting another Speedbird 9 incident.

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There is very little ash in these eruptions. The erupted material is molten.

From the last episode:



And later on in the report:


No changes have been detected in the East Rift Zone or Southwest Rift Zone. A VAN/VONA will be issued when sustained lava fountaining ceases and the eruption is paused, or earlier if the situation warrants a further update.

Kīlauea Volcano Alert Level/Aviation Color Code remain at WATCH/ORANGE. All current and recent activity is within Hawaiʻi Volcanoes National Park.


https://www.usgs.gov/programs/VHP/volcano-updates#vonas

MyOwnSockPuppet said:

If it's chucking relatively heavy lava a thousand feet up then presumably the ash is going a lot higher. I'm surprised I can't find any flight restrictions online?
Sounds like it's almost inviting another Speedbird 9 incident.

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The amount of ash released in an eruption depends on the silicate content of the magma and on the concentration of H₂O, CO₂ and SO₂.
The viscosity of the magma increases with increasing silicate content allowing the entrapment of more gas which is released explosively by coming out of solution as the magma rises releasing the pressure much like opening a soda bottle.
This explosive release tends to fragment the magma releasing large amounts of ash into the atmosphere.

Here is the eruption type from my previous post in more detail.


The VEI (Volcanic Explosive Index) scale.


The mega-colossal eruption leading to the New England caldera in Australia wiped most flora and fauna over a vast area and was a precursor to the "Great Dying" extinction event.

Sorry for taking this thread off topic but here is another one of my AI challenges.
AI is now superior to humans in terms of accuracy of identifying rocks from thin section imagery.

I live near Mt Anakie a volcano in Australia that last erupted 1.5 million years ago and has left a lava plain, rocks and fertile soil.
The last eruption was a Strombolian type and my challenge to ChatGPT was to identify the type of eruption from two sample rock images taken from my property.



The second image is a microscopic image of the crystal structure that was deliberately left blurry in some regions as an extra challenge since microscopic images have a limited depth of focus.



I allowed ChatGPT to also analyse the raw images which contained camera and lens information so it could determine the image scales and therefore the dimensions of the porous and crystal structure in the images.

Here is ChatGPT's analysis.

Yes — based on both the visible porosity in Rock 1 and the fine-grained, vesicle-rich texture in Rock 2, this sample is almost certainly a vesicular extrusive volcanic rock, likely scoria or vesicular basalt.

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Observations and Interpretation​

️ Rock 1 – Vesicular Texture​

• Displays many rounded cavities (vesicles), which are gas bubbles that formed during rapid cooling as magma ascended and depressurized (Wikipedia).
• This texture is typical of vesicular basalt/scoria, common in effusive or mildly explosive basaltic eruptions (SpringerLink).

Rock 2 – Microscopic Fine-Grained Matrix​

• The image shows a very fine-grained or aphanitic groundmass, with tiny crystals (<1 mm), consistent with rapid cooling at or near the surface (Quizlet).
• You can also note scattered small crystal fragments (phenocrysts), indicating a porphyritic texture—slow crystallization at depth followed by faster cooling during eruption (Geosciences LibreTexts).

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Inferred Eruption Type​

• Effusive, basaltic eruption: Low-viscosity magma with gas exsolution produced lava flows or thin sheets, forming vesicular basalt.
• Mildly explosive/strombolian style: If the rock contains discrete scoria clasts or bombs, this would indicate Strombolian activity—common for basaltic, gas-charged magma (smu.edu).

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✅ Summary​

Feature	Interpretation
Vesicular texture	Gas-rich basalt indicating surface degassing
Fine-grained groundmass	Extrusive cooling—surface emplacement
Possible phenocrysts	Multi-stage cooling—intermediate depth then eruption
Combined characteristics	Likely vesicular basalt/scoria from effusive to mild eruptive (e.g., Strombolian)

Bottom line: These microscopic and macroscopic textures point to a basaltic volcanic eruption, with rapid degassing and cooling, not a high-silica explosive event (like Plinian). Instead, it fits with scoria-forming Strombolian or effusive basaltic eruptions.

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Would you like to dive deeper into vesicle size analysis or crystal population studies to refine the eruption classification?

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It correctly assessed the eruption type as Strombolian.

The post-episode 28 evolution of the volcano has reached the point where typically there would be an eruption about 24 from now in either direction. The ongoing inflation of the summit from magma flowing into the storage system that directly feeds the eruption. Under prior conditions (for the last few months) at this level of inflation we would be seeing time-varied glow from the two vents and then intermittent spattering. After that there could be hours to a day or so of "gas-pistoning" where the magma level rises near to the opening and may briefly overflow before retreating downward without fountaining. That could also go on for many hours up to a day or so, before the primary eruption begins with low fountains and overflows that transition to high fountaining as the degassed magma at the top of the column is pushed out and the fountains get pushed by gasses coming out of solution just like an uncapped bottle of pop.

That hasn't happened. No sign of major, periodic glow. No magma rising near the surface. No spattering. Something has changed. One thing we do know is that the south vent has been weakening in outflows in recent episodes, with none in the last episode and a lot of lava piled on top of it. That vent may be dead. Slumping of the ejecta from the last episode has also partially blocked the north vent. Let's see what the USGS report for today said:

"Incandescence in the crater last night was limited, mostly to a crack system on the tephra cone just above the north vent. Glow from the north vent itself was sporadic. Uncrewed aircraft systems (UAS, or drone) images captured yesterday morning showed no visible molten lava within the north vent at that time."

Here is that view:



The vent seems to be at least partially stuffed up. Here is the USGS analysis:

"Summit inflation resumed at the end of episode 28 on July 9, and low-level degassing and seismic tremor persist, all of which indicate that episode 29 is near. The rate of inflation suggests it will likely occur July 18 (today). However, slumping of the tephra cone into the north vent at the end of the episode 28 created a blockage; UAS (drone) images captured Thursday, July 17, show that debris has filled the top of the north vent. Thermal data showed the plug to be hotter than the surrounding rock, although not incandescent. The small amount of persistent glow and significant degassing indicate that the north vent is not sealed tightly. Still, clearing the plug may require additional pressurization to initiate the next episode, delaying the onset of lava fountaining."

The magma keeps entering the system. It's got to go somewhere. Where and where we will see. If this has to break through the blockage and requires additional system pressure, the eruption could begin without as many warning signs as earlier episodes.


Now for a bit of fun:

Here's one additional from today's photo collection (north is up):



The dark "oval" on the right half (with the "smoking" north vent on the left end of it) is most of the 2018 caldera. (It is about 1 km wide.) The larger tilted "oval" surrounding it in gray and dark gray is the 1500 CE caldera. The brown shading on the left side of the caldera, both above and below the gas cloud is the tephra field from this eruption. Nice!

To contrast that the smaller gray oval just east of the main caldera is the old pit crater Kilauea Iki, which was filled by a spectacular, periodic fountaining eruption in 1959 with fountains of similar height. (The lava lake in the crater had a molten core for decades.) The "little" brown mound on the left edge of the crater is the tephra cone Pu'u Pua'i is 70 m high.

After an extended period with no preliminary signs, low-level eruptive activity has begun. We can't say if it will go into the major phase with fountains shortly, or if it will take hours or days. The usual note about live video in posts #5, 12, and 20 applies.

Hans Blaster said:

After an extended period with no preliminary signs, low-level eruptive activity has begun. We can't say if it will go into the major phase with fountains shortly, or if it will take hours or days. The usual note about live video in posts #5, 12, and 20 applies.

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I'll let the HVO mid-eruption update open this up:

"Kilauea Message 2025-07-20 09:30:46 HST: Episode 29 is certainly different. The "nozzle" like shape of the vent exit has broken down allowing lava to spray in multiple directions and preventing the fountains from growing higher."

So far, after several hours the maximum height has been about 60-70 m, well below the 300 m mark that had been broken for many consecutive episodes. This image illustrates it well:



This is pretty typical for this particular episode. The fountains are staying within the crater (below the rim) and not piling material (partially cooled by flying through the air for several hundred meters) in the giant mound that has been build over the last few episodes on the left side of the image (including much of the foreground). Instead it is forming streams that have spread across the crater floor, covering a large portion of it already.