July 6: Living With the 1% Possibility of Caldera Collapse

USGS, July 6, 2018. Dawn at Fissure 8. (Full-sized)
Today’s Eruption Summary

The Lower East Rift Zone eruption continues pretty much as usual: Fissure 8 feeding a lava river with occasional short-lived overflows. The main lava channel no longer reaches the ocean, but crusts over a half mile from shore and dives into the lava delta, oozing out at multiple points on the northern side. One especially large “ooze-out” makes a short flow on the north side of the flow field near the last few Kapoho Beach Lot Houses, a few of which are hanging on. Fissure 22 is weakly spattering with a weak flow to its east. Today’s summit explosion occurred at 6:04pm, equivalent of M5.3. Thick fog obscured the livestream view.

July 6, 2018, USGS. Ocean Entry at Kapoho. (Full-sized)

So that’s all routine, if a volcanic eruption can ever be routine. The big news today actually took place last night (see what happens when I finish my posts early?):

July 5 Volcano Community Meeting

Thursday evening, there was an important community meeting in Volcano Village. Mayor Harry Kim, the USGS and Civil Defense outlined the extremely unlikely but potentially life-threatening (to people near the summit) possibility of large-scale caldera collapse. I’ve transcribed the meeting here. BigIslandVideoNews excerpted the crucial 4-minute presentation from HVO’s Tina Neal:

Preceding this meeting was a long-expected document from USGS: Volcanic Hazard at the Summit of Kīlauea UpdateWhile the Kīlauea Summit Earthquakes FAQ explained what is happening, this new update to a May 8th report summarizes what the USGS thinks might happen at the summit before this sequence is over, based on the volcano’s distant past.

During the Q&A session, a resident asked about the odds for the worst-case scenario, a large-scale caldera collapse with explosive activity. Harry Kim took the mike from Tina Neal and said, “Like you, we always like to know percentage odds. And she knows; I asked her that. And I’d like to answer because she said, ‘One percent.'” [Tina went on to explain how they arrive at such probabilities; she wasn’t being flippant.]

Another reassuring quote from the Q&A session:

Don Swanson: “I think that the evidence we have today looks to me as if [the subsidence/collapse] is going to be confined to within the caldera, because the outermost circumferential fractures that have been occurring on the caldera floor have not extended outward in the last 2-3 weeks or so. So to me, that suggests that they may be defining the outermost limit of potential caldera collapse.”

USGS: “The WorldView-3 satellite acquired this view of Kīlauea’s summit on July 3. Despite a few clouds, the area of heaviest fractures in the caldera is clear. Views into the expanding Halema‘uma‘u crater reveal a pit floored by rubble. HVO, on the northwest caldera rim, is labeled.” (Full-sized)

The reason for telling people about the remote possibility of catastrophic caldera collapse is that if it does happen, people need to be prepared to evacuate and not think they can “sit it out”.  While Kilauea’s largest explosive events in its past history have a range of only a few miles, Volcano Village is within the hazard zone of “worst case scenario” eruptions.

(The reason Kilauea’s biggest explosions are small potatoes compared to Krakatoa and St. Helens is that its lava has much less silica content, so it can’t hold in as much pressure as they can. They’re pressure cookers; it’s more like a pot with aluminum foil over the top.)

Now back to the here & now.

USGS Maps of Lower East Rift Zone
July 6, 2018, 12pm. USGS map of Lower East Rift Zone lava flows. (Full-sized)
July 6, 2018 6pm. USGS Thermal Map of LERZ. (Full-sized)
From Other Agencies

From other geologists
July 6 Fire Dept overflight

Today’s dawn overflight album (146 photos, 8 videos) from the Fire Dept posted on Civil Defense’s Flickr is eerily beautiful:

(helicopter noise warning)

07/06/2018: Kilauea, HI - East Rift Zone Eruption

07/06/2018: Kilauea, HI - East Rift Zone Eruption

07/06/2018: Kilauea, HI - East Rift Zone Eruption

07/06/2018: Kilauea, HI - East Rift Zone Eruption

07/06/2018: Kilauea, HI - East Rift Zone Eruption

07/06/2018: Kilauea, HI - East Rift Zone Eruption

I think I may see a source for at least some of the lava boats— look at the inside lip of the cone:

07/06/2018: Kilauea, HI - East Rift Zone Eruption

Fissure 22 fuming in the distance behind PGV:

07/06/2018: Kilauea, HI - East Rift Zone Eruption

07/06/2018: Kilauea, HI - East Rift Zone Eruption

From local news outlets
June 5 mick Kalber Overflight

According to his notes, that mess by Kapoho Crater is apparently what sent that flow over the surface of part of the delta on the north side towards Kapoho Beach Lots.

USGS Q&A On Social Media

Q: Any info on what’s happening with the damage to Hwy 11 by mile marker 30?
USGS: It appears that an old lava tube has collapsed and taken part of the road with it. The spot had already been patched multiple times, and a former HVO employee says that that same hole opened during the 1975 earthquake and at the start of the Pu`u `O`o eruption in 1983.

Q: Tina Neal mentioned an “ash hurricane.” Where did that term come from?
USGS: “That’s a very informal term. She was talking about a pyroclastic flow or surge, which is a flow of hot ash and gas that can move with incredible speed along the ground. Colloquially, some people refer to it as an ash hurricane, but that’s really just meant to help visualize the speed.”

Q: Did today’s overflight show any more lowering of lava levels in cone, perched pond, channel?
USGSNo, there was no appreciable change in the activity at the cone. Fountaining is still very low and confined within the cone, but vigorous and feeding the channelized flow at about the same rate as yesterday.

Q: Yesterday’s update said fountain height lower, upper channel not as full. How about today?
USGSIt is similarly low today, although still zipping right out of Fissure 8 at 30 km/hr.

Q: Latest estimates on lava flow speed/volume at standing wave area?
USGS: The average velocity near fissure 8 is 5 m/s with a max of 9 m/s, and the flux is around 100 m3/s at that vent.

Q: [Rude person daring HVO scientists to spend the night at the summit, as if this will somehow validate their analysis.]
USGS: Many of the HVO scientists are, in fact, still at their homes at the summit. Those who are not were living inside the Park, and because it is closed, they were forced to leave their homes.

from other Photographers & Social Media

Looking back on the destruction of past eruptions:

Massive river of lava!Fissure 8 is the source and can be seen in the upper left. Facing west, what you see is about…

Posted by Db Photo at Primary Focus on Friday, July 6, 2018

It always gives some perspective to have a lava boat in a photo for scale. Sunrise scene in Kapoho of “The Hot Spot” of …

Posted by Db Photo at Primary Focus on Wednesday, July 4, 2018

PRINTS AVAILABLE IN PROFILE LINK 🤙🏼 . Photographs in this collection were captured at the first appearance of Fissure 1, which began on May 5, 2018, in Leilani Estates. These historic visual documents of the eruption on Hawaii Island span the course of eight weeks in the areas of and around Leilani Estates, Lanipuna Gardens, and Kapoho in chronological order. The fissure eruption has caused many to feel mixed emotions of awe and tragedy. Rapid currents of lava continue to change more than 11 square miles of our island landscape. More than 660 homes have been destroyed, displacing thousands of residents while pets and wild animals continue to be rescued from many isolated areas. While many now are out of immediate danger, lava continues to rapidly flow from Leilani Estates to Kapoho with no significant signs of change. . Proceeds from print sales will be donated to Pu’uhonua o Puna and Hawaii Community Foundation through Lyman Museum. A portion of proceeds will also help to recover eruption documentation expenses. These photographs were created to not only help our local community awareness but to also provide accurate and respectful information to mitigate inaccurate and sensationalized news coverage to stabilize our tourism economy. . Mahalo to businesses, organizations, and individuals supporting eruption evacuees and ohana who can no longer return home. While massive destruction has impacted many of us, the creation of friendships, partnerships, and community bonds shine brightly in the midst of disaster. It is inspiring to meet so many people who continue to make life safer and more comfortable for others. Special thanks to incredible friends, businesses, and government agencies who allowed or helped to acquire legal access to help document the eruption and last remaining tides of our neighborhoods. . My respect and best wishes go out to all who have been impacted by the eruption experience. There are no words to describe the amount of loss, personal tragedy, and stress our community has been experienced. . Mahalo nui loa, Andrew Richard Hara . #leilani #lava #bigisland #fissure #eruption #volcano #hawaii #kilauea #kapoho #emergencyfund @hawaiinewsnow

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