August 11, 2018. USGS: “The UAS team (Unmanned Aircraft Systems) flew a mission over fissure 8 to assess conditions within the cinder cone. As shown, fissure 8 contains two small ponds deep within its crater. One pond slowly circulates with an incandescent surface while the other pond is stagnant with a crusted top.” (Fuil-sized)
Weekly Eruption summary
So it’s finally arrived, the end (or at least intermission) of Fissure 8’s endless outpouring of lava from May 27 to August 4. The shutdown happened at the end of last week over a period of just 2-3 days.
August 11, 2018. USGS: “The fissure 8 cinder cone is currently about 30 m (100 ft) tall with a very broad base. Sulfur dioxide (SO2) emissions are low, reflecting the diminished activity of the lava ponds in the cone.” (Full-sized)
Fissure 8 isn’t quite dead. There’s lava pooled deep down the cone, bubbling weakly. Residual lava is still draining out of the lava delta into the ocean, some of it quite near the now-famous Pohoiki Boat Ramp. But most of the surface channels have drained and solidified.
August 11, 2018. USGS: “Close view of the Pohoiki boat ramp during this morning’s overflight. The southern-most flow margin has not advanced significantly toward the Pohoiki boat ramp, but black sand and larger fragments from the entry areas have washed ashore to create a sand bar and beach at this site. Geologists observed several small lava streams trickling into the sea along the souther portion of the lava delta, producing weak laze plumes.” (Full-sized)
The volcano’s summit has settled, too. The caldera floor isn’t inflating or deflating, and the swarms of earthquakes and summit collapses have stopped.
So now the question becomes: how long do geologists, national park staff and residents wait before deciding it’s safe to start repairing the damage? Past Lower East Rift Zone eruptions have paused for days, even weeks. So scientists and officials continue to warn that this eruption could resume at any time.
August 7, 2018. USGS: “Civil Air Patrol captured this image of Kīlauea’s summit yesterday (August 7, 2018), providing a stunning view of Halema‘uma‘u and the collapsed area within the caldera. Prevailing trade winds have blown much of the ash emitted during earlier explosions to the southwest (left), where thin layers of light-colored volcanic ash now blanket the landscape. Plumes of smoke rising from the flank of Mauna Loa were from a brush fire that continues burning today. Mauna Kea is visible on the upper right horizon; the crater visible at bottom center is Keanakāko‘i.” (Full-sized)
This week’s Volcano Watch column from Hawaiian Volcano Observatory, written August 9, addresses exactly that question:
Also, it looks like I missed an August 6 USGS news media briefing discussing the eruption’s apparent shutdown (full audio).
Now let’s look back at recent images and videos posted on HVO’s Photo & Video Chronology page, which only shows the 10 most recent posts— so these are visible there now, but won’t be in the future.
First of all, remembering past collapse events— with sound! Full-sized video posted here, or a faster-loading small version on Twitter:
Watch the ground shake and hear the roar of rockfall, in this video taken July 5, 2018: USGS cameras at Kīlauea Volcano's summit record a collapse event. https://t.co/VFDeSUjsFSpic.twitter.com/31JfblmDdC
On August 7, USGS/HVO took an overflight of the summit. Warning, the video’s a little jerky. Here’s the full-sized version, or a Twitter preview:
#HVO update for Kīlauea Volcano’s summit: low rates of seismicity and deformation, the most recent collapse event was August 4. Video from helicopter overflight shows dramatic changes. https://t.co/utimL1Pix0pic.twitter.com/Zza1WJOd8Q
I posted the Civil Air Patrol photo from August 7 above, with a brush fire burning on Mauna Loa’s flanks. Here’s two spectacular views from August 9:
August 9, 2018. USGS: “lear weather this afternoon afforded a stunning view of Kīlauea’s summit, which has been “quiet” since August 4, with no significant subsidence or collapses. The flat ledge shown here (center) is part of the caldera floor that was located west of Halema‘uma‘u. It and other parts of the caldera floor dropped during summit collapse events that occurred between mid-May and early August.” (Full-sized)August 9, 2018. USGS: ” As Halema‘uma‘u collapsed, older volcanic deposits (layers of ash and lava flows) and features hidden for decades have been revealed in the crater walls, visible here with the aid of a telephoto lens.” (Full-sized)
And here we are at present, August 12. A hazy day provides more distant views of the caldera from (I think) the northeast rim/Volcano House area.
August 12, 2018. USGS: ” Kīlauea’s Halema‘uma‘u crater was quiet again today, with only degassing from cracks and fumaroles noted by HVO observers.” (Full-sized)
Crater Rim Drive, down but not out [of sight]!
August 12, 2018. USGS: “In this zoomed photo, the large slump block on the south side of Halema‘uma‘u still preserves a largely intact short stretch of Crater Rim Drive.” (Full-sized)
Lower East Rift Zone: Fissure 8
August 7, 2018. USGS: Early morning overflight view of the small lava pond within the fissure 8 cone. Weak lava bubbling and convection was occurring in the pond, which was around 5-10 m (about 16-33 ft) below the channel spillway. (Full-sized)August 7, 2018. USGS: “Lava in the fissure 8 channel is now crusted over. Fissure 8 and other inactive fissures are steaming the background, a common sight during early morning overflights (cooler air temperature results in more condensation, making steam more visible).” (Full-sized)August 7, 2018. USGS: “Aerial view of the fissure 8 cone and spillway captured by Civil Air Patrol during their overflight on August 7, 2018. View is toward the south.” (Full-sized)August 7, 2018. USGS: “This August 7th Civil Air Patrol photo provides a closer view of the fissure 8 cone and the small pond of lava within the vent. The lava is below the level of the spillway that fed the fissure 8 channel from May 27 to August 4, 2018.” (full-sized)August 8, 2018. USGS: “HVO scientists checking on the status of the lower East Rift Zone fissures this morning reported that no audible noise could be heard from the fissure 8 cone (near center).” (Full-sized)August 10, 2018. USGS: “The Unmanned Aircraft Systems (UAS) team flew over fissure 8 today, providing this aerial view into the cinder cone. The pond of lava within the vent has receded, and was about 40 m (130 ft) below the highest point on the cinder cone’s rim today.” (Full-sized)
Thermal maps from the past week show the lava pond in Fissure 8 subsiding and crusting over:
August 9, 2018 USGS thermal map of LERZ: “This thermal map shows the fissure system and lava flows as of 6 am on Thursday, August 9. Residual lava in the Fissure 8 flow continues to drain, feeding numerous small ocean entries (shown in main map). In the Fissure 8 cone there was a small, mostly crusted, lava pond (shown in small inset map).” (full-sized)
The handheld survey covered a little less area this time, probably reflecting the fact that any lava left beneath the surface of the “Kapoho Lobe” (the more northerly part of the delta) is too insulated/cool for the thermal cam to see.
August 11, 2018. USGS: “This thermal map shows the fissure system and lava flows as of 6 am on Saturday, August 11. Residual lava in the Fissure 8 flow continues to drain, feeding numerous small ocean entries (shown in main map). In the Fissure 8 cone there were two small lava ponds (shown in small inset map).” (Full-sized)
Isaac Hale Park / Ocean Entry / Delta
I freely admit I called it too soon, and I’m glad I was wrong. It looks like Isaac Hale Park may be salvageable.
August 7, 2018. USGS: “Active breakouts on the western side of the Ahalanui lobe of the fissure 8 flow near Isaac Hale Beach Park were visible this morning. There was no apparent advance of the flow toward the Pohoiki boat ramp since ye[s]terday.” (Full-sized)Here’s an August 9 overflight video of the LERZ active ocean entry (full-sized video here):
Pardon me for repeating an image, but this is important.
August 11, 2018. USGS: “Close view of the Pohoiki boat ramp during this morning’s overflight. The southern-most flow margin has not advanced significantly toward the Pohoiki boat ramp, but black sand and larger fragments from the entry areas have washed ashore to create a sand bar and beach at this site. Geologists observed several small lava streams trickling into the sea along the souther portion of the lava delta, producing weak laze plumes.” (Full-sized)
Hopefully that sand bar will discourage looters, who were reportedly using Pohoiki to access homes/properties that were not destroyed by lava, but simply cut off (in mid-May ,lava flows from Fissure 21 reached the coast a little farther to the west).
Looks like nobody’s going to be able to build on the new land for quite some time. Quite apart from the instability of lava deltas, this looks like rough terrain:
Considering complaints about looters, having the boat ramp silted up may be a blessing, until residents can return and start salvaging their homes and farms. (For a while, the boat ramp provided the only access point to homes/farms cut off by earlier lava flows reaching the ocean to the southwest in May, and Fissure 8’s lava delta to the northeast.)
Maps of LERZ this week
Before I forget, here’s this week’s two maps.
USGS/HVO map of LERZ as of August 7, 2018, 11 am. (Full-sized)
It’s subtle, but I think they show less lava at the ocean entry points. Also, that overflow just west of Kapoho Crater had stopped by August 9:
August 9, 2018 2 pm USGS/HVO map of LERZ. (Full-sized)
Last but not least, here’s a few…
Photos of HVO Fieldwork
August 8, 2018. USGS: “During this morning’s field observations, an HVO geologist collected a sample of pāhoehoe from the August 2 overflow of the fissure 8 channel. For more information on what can be learned from lava samples, please read HVO’s July 27, 2018, Volcano Watch article.” (Full-sized)
August 11, 2018. USGS: “Geologist hikes to the rim of Pu‘u ‘Ō‘ō to clean the external housing lenses of two webcams on the rim of the new crater that formed on April 30, 2018.” (Full-sized) [I’m guessing they’re the two north rim webcams]Just as they’re keeping an eye on Pu’u O’o although it seems to have gone to sleep for good, they’re still watching and checking for cracks on the roads of much-beleaguered Leilani Estates, where the lava eruption started.
August 12, 2018. USGS: “Fissure 8 may have slowed down, but HVO scientists are still on the ground in Leilani Estates, monitoring old ground cracks and marking ones that haven’t been surveyed before. Monitoring these cracks over multiple days and help detect any new signs of magma movement beneath the ground, one of the indicators that fissures might reactivate. As of Sunday August 12, no unusual changes in cracks were noted.” (Full-sized)
I started this post too late. Stay tuned; I’ll be doing a scour of other official agencies, local news media, social media and photographers tomorrow. [UPDATE: here’s the “tomorrow” followup post.]
