September 2: A Few Signs of Life Deep in Fissure 8

 

Saturday, Sep 1, 2018, 6:00 pm – Kilauea's lower east rift zone overflight: Another angle of fissure 8, with a small lava pond within.

Posted by Extreme Exposure Fine Art Gallery on Sunday, September 2, 2018

This Week’s Eruption Summary

While no glow or incandescence was reported within Fissure 8’s cone for most of the week, Saturday 9/1 showed a few life signs remain in the LERZ: weak spattering from one spot, and in the evening new lava came out to cover most of the crater floor. But its sides have been slumping and falling in, as have the levees of the now solidified lava channel. While Fissure 8 and some of the surrounding vents continue to steam and fume, SO2 emissions remain low there and at the summit.

August 30, 2018. USGS: “The fissure 8 lava channel (center) and levee (foreground), looking toward the northwest. Loose rubble and Pele’s hair (lower right) are strewn across the levee surface.” (Full-sized)

No active ocean entries have been seen for the past few days, suggesting that all the residual lava from Fissure 8 has stagnated or drained out.

August 30, 2018. USGS: “Lower East Rift Zone lava flows entering the ocean have built a lava delta over 875 acres in size, but no active ocean entries were observed by HVO geologists on this morning’s overflight. View to the southwest.” (Full-sized)

This week has been a time of repair and taking stock. USGS geologists have been replacing lost or damaged monitoring stations (including the UWE tiltmeter, back on HVO’s deformation page). The drone crews have been out after Hurricane Lane came through to take new detailed aerial surveys of Kilauea’s summit (August 30 video) and Fissure 8 (August 21 video).

Screencap from August 30, 2018 UAV video survey of Kilauea summit.

They also posted an updated timelapse video of HVO’s panorama cam of Halema’uma’u from April 14 through August 20:

This week’s Volcano Watch newsletter from HVO describes how “Scientific community lends a hand to measure Kīlauea’s changing shape.” This eruption required all hands on deck and every last scrap of equipment they had, and then some.

Another screencap from the August 30 drone survey of Halema’uma’u Crater and its surroundings. Piece of Crater Rim Drive a long way down in the crater.More photos after the cut, plus some notes on the park’s status.

Fissure 8 earlier in the week:

August 27, 2018. USGS: “No incandescent lava was visible in the fissure 8 cone during HVO’s morning overflight. Steam persists on the cone and flow field due to heavy rainfall over the past several days from water seeping into still-hot rock.” (Full-sized
August 27, 2018. USGS: “Only one small ocean entry near Ahalanui was visible during this morning’s overflight.” (Full-sized)

The next one is best viewed full-sized on a computer screen.

August 28, 2018. USGS: “In this panorama of the fissure 8 lava channel, the greatest measured depth was 9.5 m (31 ft). “Bathtub rings,” lava adhered to the levee walls, indicate former high levels of lava flowing through the channel. Many of the levee walls and ramparts are beginning to collapse into the empty channel.” (Full-sized)

A few scenes from the new lava field (as always, be sure to note full-sized trees for scale):

August 30, 2018. USGS: “Void spaces within the cooled lava channel and along the channel margins create hazardous conditions on the fissure 8 flow field. Here, part of the void is visible, but a fragile veneer of lava hides other parts of it (upper right).” (Full-sized
August 30, 2018. USGS: “During their field work, HVO geologists collect lava samples along the fissure 8 channel to learn more about the inner workings of the eruption. This sample is a lightweight, frothy basaltic pumice, called reticulite, which is produced by lava fountains.” (Full-sized)

And one more check on Pohoiki:

August 31, 2018. USGS: “A sand bar, comprised of black sand and lava fragments carried by longshore currents from the lava delta, continues to block the boat ramp at Isaac Hale Beach Park.” (full-sized)
From Other Agencies

With Kilauea quiet, eyes turn to Hawaii Volcanoes National Park’s efforts to reopen. HVNP has created an updates page reporting on their progress. They’ve also been hosting “Talk story” gatherings at their Kahaku Unit, which was farther away from the summit and stayed open, inviting residents and visitors to weigh in on “what the future of the park should look like.”

From Local News Agencies

Nice synopsis from BIVN (accompanying Sep 1 article: “Kilauea Summit Update — National Park Opening Details”

Articles noting activity (what there was of it) this week, just in case anyone stumbles across this blog later trying to track activity day by day:

And all the other Kilauea-related news.

This video and article is making the rounds of mainland ABC affiliates (i.e. it’s the first Kilauea news many mainlanders have seen in months):

“Forces of nature: How Kilauea eruption, Hurricane Lane flooding changed Hawaiian landscape”

Also, for what it’s worth, there’s a Cat 4 Hurricane, Norman, heading towards the Central Pacific. Currently forecast to pass well NE of Hawai’i, but it’s a ways out and may have some impacts.

Aug 29 Helicopter Overflight of LERZ

Really good views of the now solidified lava channel starting around 0:50; I think increased steam from Hurricane Lane was marking the edges of the levees:

That bitty island is back, by the way. Good clear views of the lava delta now that laze isn’t hiding it.

Bruce Omori posted 14 photos plus observations on this overflight on Facebook. A few excerpts:

Wednesday, Aug 29, 2018, 6:00 am – Kilauea's lower east rift zone overflight: The growing new sandbar at Pohoiki has created a cool shore break, and has also trapped a few bodies of water.

Posted by Extreme Exposure Fine Art Gallery on Thursday, August 30, 2018

Wednesday, Aug 29, 2018, 6:00 am – Kilauea's lower east rift zone overflight: Rising steam along the edges of the perched channel accentuated the path of channelized flow toward the sea.

Posted by Extreme Exposure Fine Art Gallery on Thursday, August 30, 2018

Wednesday, Aug 29, 2018, 6:00 am – Kilauea's lower east rift zone overflight: Two trees…

Posted by Extreme Exposure Fine Art Gallery on Thursday, August 30, 2018

Bruce also posted 9 photos and observations from a Saturday, Sep 1 evening overflight in which he observed some activity down in the Fissure 8 cone.

Someone posted one of Bruce’s photos of Fissure 8 from his late Saturday overflight to the USGS Facebook page. USGS replied:

“This is pretty minor activity, and is a common sort of process as eruptive vents wane — they tend to burp a few times before going completely quiet, but larger reactivations are also possible, which is why vigilance and care continue to be requirements. We’ll have geologists out this morning to check on Fissure 8.”

USGS Q&A on Social Media

Questions have dried to a trickle, along with the tin hat conspiracy theorists predicting dire things that didn’t come true.

Again on Facebook (which doesn’t let us embed, grr):

Q: [Trying to get an idea of size of Fissure 8 cone]

USGS: Assuming a one-story building is ~12 ft high, a 13-story office building would fit inside the fissure 8 cone.

Q: What would you expect to see for a “closing” rift? At what rate would the intrusion cool? And how would it be noticeable?

USGS: We are still monitoring crack temperatures and carefully watching for ground deformation trends in the lower East Rift Zone. The most recent deformation results in the LERZ do not show patterns that would be consistent with rift opening or closing. If the subsurface magma intrusion is cooling, those effects are not yet strong enough to be detectable. Neither do we see signs of inflation/reactivation. To answer your second question, cooling may take decades. Some of the first lavas to erupt in LERZ were leftover from the 1955 eruption – the thick and viscous magma was reheated and pushed out ahead of new magma coming down the East Rift Zone.

Q: Current SO2 rates? Signs of magma returning to summit?

USGS: Sulfur dioxide emission rates at the summit, Puʻu ʻŌʻō, and lower East Rift Zone are all drastically reduced; the combined rate (< 1,000 t/d) is lower than at any time since late 2007. Seismicity, deformation and tilt at the summit are negligible. We continue to monitor for trends about what might happen next.

Q (posted Aug 30): When do we call it pau?

USGS: It’s possible that the slowdown reflects the end of the LERZ eruption and summit subsidence but we are going to hold off calling it pau at the moment. We’ve essentially flat-lined and are watching for trends now. Is the system going to repressurize? Continue to subside? We are tracking the subtle clues (gases, seismicity, ground deformation) that might give us an indication where we are headed.

 

Other Social Media

At this point #Kilauea and related tags are a wasteland as far as current information; scaremongers are posting several-month-old videos (some not even of Kilauea) as if it’s still happening.

But here’s one diamond in the sludge: