Informing the public without panicking them about an extremely unlikely but life-threatening hazard is tricky. So it’s taken the USGS a while to release this document which they’ve been promising the residents of Volcano:
This post got long, so I’ve moved the Q&A session to Part 3. Again, I’m transcribing what HVO geologists had to say at the June 28 Volcano Village community meeting.
Part 1 was Kyle Anderson’s talk on seismicity and ground deformation— lots of nitty gritty science— while Part 2 was Don Swanson’s slideshow of some of the visible changes he’s observed within Kīlauea Caldera, with a lot of photos I haven’t seen anywhere else.
Here’s the video of the whole meeting.
Here’s my transcription of the Q&A session. A lot of these questions have already been answered online, but I like hearing direct, personal responses from some of the senior HVO scientists:
This continues my transcription of the Thurs Jun 28 USGS presentation at Volcano Village. Part 1 transcribed HVO Scientist-in-Charge Tina Neal and seismologist Kyle Anderson’s remarks. Part 2 covers senior volcanologist and my longtime hero Don Swanson’s remarks.
Here’s the video of the entire 1.5 hour meeting. Don’s presentation starts at 15:50:
It sounds like Swanson’s been holed up in Volcano House after HVO was evacuated. (Kyle Anderson: “Don has spent more time viewing this eruption from the summit than anyone else.”)
Title of talk: “Comparisons of Halemaʻumaʻu Crater, May 19 through June 28 Viewed from dining room table of Volcano House”
The data that Kyle showed are absolutely magnificent. What I want to do now is to show you some photographs of features that I’ve been able to see during my observations. The first will be a series of photographs of Halemaʻumaʻu taken from the seat in the dining room of the Volcano House hotel where I sit and observe things.
On May 19th, of course, things were just starting to get going, but over here on June 13th, you can see that the crater has widened dramatically, and notice that it’s also dropped to the top of the tree which was way below the— it’s come way down. It isn’t because the tree is growing! It’s because the crater is dropping down.
Now we’ll go to this next period, June 13th to the 17th.
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.
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.
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.”
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.
“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.