Tag: steam explosions

July 30: Day 88 Matches 1955 Eruption Duration

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Today’s Eruption Summary

Eruption continues as usual with three minor things to note. First: “fuming” on the southwestern margin of the flow near Pohoiki could mean possible breakouts, according to today’s HVO Kilauea status update.

Same source also says that, rather unusually, a 4.1 earthquake at 10:02 pm was felt all the way to Hilo, far more widely than the stronger summit collapse events, possibly because it was at a depth of 7 miles.

And finally, Tuesday will mark the 89th day of the eruption, surpassing the length of the 1955 Kapoho eruption which had previously held the record for the longest LERZ eruption since westerners arrived and began keeping records.

From Other Geologists

Erik Klemetti’s Rocky Planet blog in Discover magazine invites readers to “Check Out How The 2018 Eruption Has Changed At Kilauea’s Summit“. Although I suspect readers of this blog are well aware of pretty much everything in that post!

I tweeted him a question about “Halema’uma’u Caldera,” which he seems to be using instead of “Kīlauea caldera.” I know Halemaʻumaʻu crater has expanded so much it could be classified as a caldera now, but so far HVO scientists have resisted doing so, to avoid confusion with the larger, older caldera.

July 30 HCFD Overflight Photos

HCFD’s July 30 album is up on Flickr. Just 12 photos plus the video clip at the top of this post. Including the clearest views we’ve seen of Isaac Hale Park in some time, since the laze plume wasn’t in the way:

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Here’s a few USGS photos from today plus the LERZ map, and overflight video and photos from Mick and Bruce:

Continue reading July 30: Day 88 Matches 1955 Eruption Duration

May 26: Good Morning, Hawai’i

Strange that something so disruptive can be so beautiful.

Hawaii Volcano Observatory Alert: Saturday at 5AM, the summit crater let off a series of explosions at 5AM sending up an ash cloud 11,000 feet that lingered for 25 minutes. Lighter winds may keep ashfall from today’s explosions mostly within the park, giving downwind communities a respite. [Edit: No such luck. Taller ash explosions today had more range.]

HVO webcam caught a nice glimpse of plume by moonlight (“exit” sign of observatory reflected in lens):

(Camera is picking up a few lights from observatory; note “Exit” sign.)

Sadly, it was not so tranquil-looking down in Leilani Estates, 25 miles away:

May 19 USGS Press Conference on Kilauea’s Explosive Side

BigIslandVideoNews just put up an edited video of Saturday’s USGS press conference. My hero Don Swanson is there. It’s INCREDIBLY informative on what they think is happening at the summit and why they think it’s a repeat of the “much smaller eruptions” of 1924 and not larger ones.

Transcription:

Continue reading May 19 USGS Press Conference on Kilauea’s Explosive Side

May 18/19: Good Summary of Eruption to Date

USGS aerial view of lava flow, May 19. (full-sized)

Volcanologist Erik Klemetti pulls everything together for us, reviewing how the Leilani Fissure lava eruptions and the summit ash/steam eruptions have progressed.

Link:

Kilauea Eruption Continues: How Long Could It Last?

The eruption at Kīlauea is still captivating the nation, as it should because this volcano hasn’t behaving like this in almost a century. I thought I’d take a moment to step back and review of the main events so far and what it might all mean for Kīlauea and the people who live around the volcano. These eruptions are separated by a long way if you look at the satellite data and should almost be treated at two different events..

Also, here’s today’s CivilDefense briefing and BigIslandVideonews’ splice of afternoon USGS briefing with geologist Carolyn Parcheta plus recent video footage.

Taking from video  (basically telling us which fissures are doing what):

Continue reading May 18/19: Good Summary of Eruption to Date

Hazards in Hawaii: Most of the State Is Just Fine, Thanks

I wasn’t going to do this, because hazard information is best left to emergency officials and experts.

But I don’t want the videos and images I’m sharing to mislead people into thinking this event is larger-scale than it is. It’s overwhelming to those who have lost homes or had to evacuate. I don’t want to downplay what they’re going through. At the same time, major hazards are confined to a very limited area, yet news media are whipping this up to apocalyptic proportions and tossing out headlines with “fears” and “anxieties” and “major” to scare people. I don’t want to add to their hype. A volcanic eruption one can watch from a few miles away without dying is moderate, not major.

So let me try to give a rundown of Kilauea hazards, and why I think it’s not greedy nor crazy for officials to be urging tourists not to cancel their visits.

Hazards from the Current Kilauea Eruption

Continue reading Hazards in Hawaii: Most of the State Is Just Fine, Thanks

May 19 – Another Ash Explosion Last Night

USGS reports another explosion last night: “At 11:58 PM Local time, a short-lived explosion at from Halema’uma’u created an ash cloud that reached up to 10,000 ft asl and was carried southwest by the wind. Possible trace ash fall may have occurred along Highway 11.”

I’m not sure whether this was a steam explosion, or just yet another of these rockfall-triggered ashclouds, like this one in 2011:

Hawaii Volcano Observatory is so lucky to have one of the foremost experts in explosive eruptions, Don Swanon, who worked on St Helens so long ago and uncovered Kilauea’s explosive history after transferring to HVO in the 90s.

From KITV May 19:

Experts on this active volcano gathered to share what they know- and what they have discovered is Kilauea has a history of explosive ash eruptions. Hawaiian Volcano Observatory geologist Don Swanson sums, “For the past 2,500 years we’ve had explosions more than 50% of the time, so this is the norm for Kilauea. But most of the explosions are minor, like we saw today, with small plumes of ash and steam rising from the summit.”

May 17, Early Morning: Steam Explosion!

May 17, 4:17 AM, the first honest-to-gosh steam explosion like they’ve been predicting (instead of just a rock and lava explosion) sent an ash cloud up 30,000 feet. Gemini Observatory caught it on timelapse:

According to volcanologist Erik Klemetti, the blast threw some 1000-pound blocks, the only place I’ve seen this. See blog post (more pics).

By morning, things had settled down:

Continue reading May 17, Early Morning: Steam Explosion!

About the 1790 Kilauea Eruption

Here’s a summary and primary sources collected by HVO geologist Don Swanson on a 1790 explosive episode of Kilauea.

Also see USGS factsheet, “Explosive Eruptions at Kilauea, Hawai’i?” compiled prior to the 2018 eruptions. Diagram from this page:

3-part diagram: at left, a full lava lake with a long chimney of magma supplying it from below; in the middle is the same lava lake with the lava level dropping way down the chimney, below the water table, so that the upper walls of the chimney are cool enough for groundwater to seep in. Rocks falling from the chimney's walls are starting to choke it. The third and last phase of the diagram shows that groundwater has heated to steam and built up pressure below the rockfall until it builds up enough steam to shoot the blockage straight up out of the chimney.
USGS Diagram Explaining Cause of Steam Eruptions

The factsheet notes that “Many of Kilauea’s pre-1924 explosive eruptions that produced significant ash deposits probably happened when the volcano’s summit crater was so deep that its floor was below the water table, letting ground water seep in to form a lake.”

If I’m understanding correctly, they’re saying that bigger explosions may happen when there’s a lake of water, i.e. more fuel to create steam.

Edited to add: HVO’s page outlining the history of Kilauea Caldera also goes into past explosive episodes. Final paragraph:

“Having pieced together the recent geologic past of Kīlauea, scientists conclude that the volcano will eventually return to a long period of mostly explosive activity, just as it did around 1500 CE. This future explosive period will probably accompany a significant decrease in the magma supply rate and be initiated by collapse of a new caldera to the depth of the water table, which today is about 615 m (2015 ft) below the present high point on the caldera rim. For now, effusive eruptions dominate Kīlauea.”

Note: that’s a new caldera, the much larger basin containing Halema’uma’u crater within it, and the vent that’s erupting ash explosions right now was a small lava lake covering only part of the floor of Halema’uma’u. Orders of magnitude different in terms of size. Also, changing the location of the active vent doesn’t mean the magma supply inside is dropping.

May 9-10: USGS Warns of Possible Steam Explosions

Attention shifted back to the summit on May 9, when a 3.1 earthquake set off a rockfall that agitated the lava lake and sent up a 6000-foot poof of ash (video clip National Parks site):

Rockfall into Halema’uma’u lava lake sends up plume of ash, 8:27 May 9.

Rockfalls caused poofs of ash like this even back when the lava lake was full, but that was more than usual. (See also USGS video from May 7, when lava lake was still visible, showing how falling rocks agitate it).

However, that was just a teaser. The big news was the dropping lava lake…

…prompted HVO to issue its first warning about steam explosions if the lava dropped below the water table.

Hawaii Volcanoes National Park closed Friday May 11 as a precaution, since the lava lake was projected to reach the water table sometime that day. For the next few days it continued to send up a white plume of steam and/or ash clouds when rocks from the sides of the chimney fell in:

[USGS] May 11, 9:12 AM: second ash explosion
On steam (phreatic) explosions:

Continue reading May 9-10: USGS Warns of Possible Steam Explosions