August 5: Pele Taking It Easy This Week

“Since May 16, 2018, the crater depth has more than tripled and the diameter has more than doubled.” ~ HVO

Kilauea summit changes, 2018. USGS: “Here’s another ‘then and now’ look at Halema‘uma‘u (view is to north). At left, Halema‘uma‘u, as we once knew it, and the active lava lake within the crater are visible on April 13, 2018. At right is a comparable view captured on July 28, 2018, following recent collapses of the crater. The Hawai‘i Volcanoes National Park Jaggar Museum and USGS-HVO can be seen perched on the caldera rim (middle right) with the slopes of Mauna Loa in the background.” (Full-sized)
Current Eruption Summary

Volcanic activity has decreased over the past few days, at both the summit and down in the Lower East Rift Zone. However, as HVO warns us (and has stated many times), eruptions wax and wane, and can even stop and start up again. So we don’t yet know whether Pele’s winding down or simply taking a breather.

But for the moment, at least, Fissure 8 is putting out much less lava than before— in fact, this morning (August 5) its level is so far down that it’s barely feeding the channel. Lava levels were already lower and sluggish, and today the river is mostly crusted over and/or moving as thicker, crumbly a’a flows. However, blockages downstream are still causing overflows and breakouts.

“View of the fissure 8 cone and spillway from HVO’s overflight early this morning, during which geologists observed eruptive activity that was much less vigorous than in past days.” (Full-sized)

Despite the slowdown at the source, lava continues to ooze into the ocean along a long section of the southern flow front. It’s edged a little bit closer to the boat ramp and local park that’s become a symbol for residents mourning the loss of so many other beloved places:

August 5, 2018. USGS: ” A diffuse laze plume afforded a clear view of Isaac Hale Beach Park and the ocean entry, which was being fed across a broad front by viscous pāhoehoe. Lava was oozing laterally, but was still about 70 m (230 ft) southeast of the Pohoiki boat ramp as of this morning.” (Full-sized)

Lava tour boat operator Ikaika Marzo did not see any signs of slowdown at the flow front this morning, and he reported that lava has claimed claimed another popular local surf spot called “Dead Trees.”

At the summit, intervals between collapse events are lengthening. As of 5 pm August 5, it’s been over three days since the last summit collapse event. Today’s mini-update on HVO’s website states:

Rates of seismicity and deformation at summit and lava output from fissure 8 have decreased since most recent collapse event at 11:55 am HST August 2. Too soon to tell if the decrease will persist. Hazardous conditions remain.

Lower East Rift Zone USGS lava map as of 10 am, August 3. (Full-sized)
Friday, August 3 USGS Thermal Map of Lower East Rift Zone as of 12:30 pm. (Full-sized)
Latest Satellite Imagery

The most recent scenes, acquired on August 1, 2, and 5, show little overall motion, which is consistent with the slowing of deformation in the summit area over the past few days. — HVO

Kilauea Caldera satellite radar imagery, May 5-August 5, 2018. (Full-sized)
Volcano Watch, August 3

And on August 3— before today’s significant lava decrease at Fissure 8— HVO posted out its weekly Volcano Watch column:

Outline of the rest of this post:
  • Summary of USGS presentation at Thursday Volcano Village meeting
  • Review of USGS eruption images from past few days (plus video)
  • News and Kilauea-related information from other official agencies
  • Kilauea-related headlines from local news media
  • Overflight photos/videos of LERZ from @Hotseathawaii, etc
  • USGS Q&A about eruption (and recent signs of change) on social media

Thursday evening Volcano Community Meeting

Thursday evening’s Volcano Village meeting (full video here) included a status update on Kīlauea’s summit from HVO geophysicist Ingrid Johanson (starting at timestamp 4:10). Johanson reports that the summit’s collapse cycle continues much as it has for the past two months: M5.3 earthquakes caused by the summit settling into the drained upper magma chamber, low SO2 emissions, not much ash since late May.

Johanson showed graphs of tilt/deflation and earthquake frequency illustrating this “collapse cycle,” and noted that the time between collapse events is increasing. Thursday’s collapse (video) was the 62nd.

Slide showing July 11 Digital Elevation Map (LIDAR) from Ingrid Johanson’s presentation. (Full-sized)

Around timestamp 11:10, Johanson posted before-and-after slides of 2009 and 2018 Digital Elevation Maps, including fairly current figures:

  • Volume loss (expansion of Halemaʻumaʻu Crater + caldera subsidence): about 800 million cubic meters, ~300,000 Olympic swimming pools
  • Slumping area is about 1000 acres [over 4 km²].  Halemaʻumaʻu was about 1 km across when this started.  [But I think “slumping” includes the wider area of the caldera floor that’s subsiding, not just H. Crater]
  • Halemaʻumaʻu Crater depth on July 22: 1575 feet (“deeper than Empire State Building is tall”), 480+ m.  It was ~280 ft deep (~85 meters) back in April.
  • [On Facebook, USGSVolcanoes stated on Aug 4, “The depth of the crater floor has increased by more than 350 meters (1100 feet) since early May, 2018.”]
  • The main floor of Kīlauea Caldera has subsided about 400 feet (~125 m) 

Around timestamp 15:40 in the meeting’s video, Johanson shows a timelapse of caldera subsidence I haven’t seen posted elsewhere in its entirely.

USGS Photos posted Aug 3-5

Fissure 8 looking subdued…

August 3, 2018. USGS: “Lava in the fissure 8 channel spillway was fairly low this morning, with the lava in the channel moving at a fairly low velocity.” (Full-sized)
August 5, 2018. USGS: ” Looking more directly into the fissure 8 vent this morning, the inner walls of the cone and lava surface could be seen. The level of lava within the vent and spillway (left) were down compared to yesterday. A dark crust, which forms as the lava surface cools, had formed on the lava with the spillway.” (Full-sized)

Views of lava channel over past few days…

August 4, 2018. USGS: “During HVO’s early morning overflight today, lava was moving sluggishly through the fissure 8 channel (from upper right to lower left in this view), well within the banks of the perched channel. The fissure 8 vent can be seen in the distance (area of blue-tinted volcanic gas emissions).” (Full-sized)
August 5, 2018. USGS: ” An ‘a‘ā flow on the western flank of Halekamahina, a cone west of Kapoho Crater.” (Full-sized)
August 5, 2018. USGS: “Lava breakouts on the north and east sides of Kapoho Crater (upper right) were also observed during this morning’s overflight. This view is from the north side of the crater; Government Beach Road visible at far left.” (Full-sized)
August 5, 2018. USGS: “Incandescent lava remained visible in a section of the fissure 8 channel west of Kapoho Crater (just visible at far left). This view is looking south toward the ocean; the laze plume rising from the ocean entry can be seen in the far distance.” (Full-sized)
August 5, 2018. USGS: “Closer view of the open channel west of Kapoho Crater. According to geologists flying over the area, the flow appeared be the result of draining from the upslope channel; no discernible movement was observed.” (Full-sized)

August 2 Pahoehoe:

Full-sized video posted on HVO website here. On FB, they specified the location of this video: “This is on the northern margin of the lava channel, which you can see moving slowly from right to left. The location is along the widest part near Pohoiki Rd & 132 just west of Lava Tree State Park.”

Ocean entry and Pohoiki…

August 4, 2018. USGS: “Multiple streams of lava were oozing into the sea along the southern lobe of the active ocean entry near Isaac Hale Park this morning.” (Full-sized)
August 4, 2018. USGS: “A slightly different view of the southernmost lobe of ocean entry lava streams. The roof of the house at Isaac Hale Beach Park can be seen through the laze plume.” (Full-sized) — note that they adjusted the lighting to bring out details in this Tweet of same photo.
Ocean entry of lava
August 5, 2018. USGS: “Closer view of the viscous pāhoehoe flow entering the ocean near Isaac Hale Beach Park this morning.” (Full-sized)
August 5, 2018. USGS: “Another view of Isaac Hale Beach Park and the Pohoiki boat ramp from this morning’s overflight. The active ocean entry and laze plume can be seen at lower left.” (Full-sized)

Meanwhile, up at the summit…

August 3, 2018. USGS: “Early morning photo of Halema‘uma‘u, taken from the northeastern caldera rim. Inward slumping of the crater rim and walls continues. Ash deposits from previous explosions and collapse events are being remobilized by gusty winds today, creating a cloud of dust on the far horizon.” (Full-sized)
August 4, 2018. USGS: “Misty weather is coming and going this morning at the summit of Kīlauea. A break in the mist allowed this clear view of Halema‘uma‘u from the northeast rim of the caldera, from which talus (rock fragments) piled at the base of the steep crater walls can be seen. With each summit collapse. rocks in the crater walls are shaken loose, widening the crater. Since May 16, 2018, the crater depth has more than tripled and the diameter has more than doubled.” (Full-sized)
From Local Gov’t Agencies

The Hawai’i Board on Geographic Names is meeting August 8 to discuss naming process for Fissure 8, as well as some other places.

Hawai’i Civil Defense has cleared out all old active alerts from earlier in this eruption, and is posting a standard daily announcement. Audio (plus footage of Fissure 8, Leilani Estates) here:

Also, not related to or caused by the eruption, firefighters have been battling a major brushfire near Waikoloa. By Saturday evening, it was 70% contained.

Another important non-eruption news item is Hurricane Hector (National Hurricane Center Advisories, NWSHonolulu on Twitter). It looks like it’s going to miss the Big Island, but there’s enough uncertainty that people need to be prepared for a hit, just in case:

HDOT continues to keep Highway 11 open by repairing damage as it appears, as well as damaged portions of Crater Rim Drive needed as an emergency route. At a Volcano Village meeting Thursday evening, Civil Defense reported on plans to build two alternate emergency routes in case earthquakes make Highway 11 impassible.

On Friday, the Departments of Health and Education announced a joint volcano response plan to address vog and ash hazards for schools and students. The new school action plans are available partway down the DOE’s Kilauea eruption webpage, which has a lot of useful disaster preparedness and assistance resources for Big Island residents.

From Local News Outlets

More Views From Above

Here’s Mick Kalber’s August 5 morning overflight of Fissure 8. Compare with August 2, when levels were already somewhat diminished, but not like this:

Bruce Omori posted 18 photos from the same @HotSeatHawaii flight, including:

Sunday, Aug 5, 2018, 6:00 am – Kilauea's lower east rift zone overflight: With the slowdown in lava supply from fissure 8, a recession within the perched channel is noticeable from this angle.

Posted by Extreme Exposure Fine Art Gallery on Sunday, August 5, 2018

That’s the perched channel where it widened out into a sort of lava pond.  As usual, look for houses for scale.

Sunday, Aug 5, 2018, 6:00 am – Kilauea's lower east rift zone overflight: The buildup of ‘a‘a in the lower channel has…

Posted by Extreme Exposure Fine Art Gallery on Sunday, August 5, 2018

Sunday, Aug 5, 2018, 6:00 am – Kilauea's lower east rift zone overflight: A view of the eruption zone from above shipwreck corner, with overflows occurring from the lower braid through the bend.

Posted by Extreme Exposure Fine Art Gallery on Sunday, August 5, 2018

Sunday, Aug 5, 2018, 6:00 am – Kilauea's lower east rift zone overflight: An active flow front, approximately 1 1/2…

Posted by Extreme Exposure Fine Art Gallery on Sunday, August 5, 2018

It’s worth checking out the rest of that album for close-ups of specific features along the changing flow field, and sharp-eyed observation notes.

G. Brad Lewis overflight photos from August 4, late afternoon:

Compare with Andrew Richard Hara’s August 2 overflight photos.

And back to August 5:

USGS Q&A on Social Media

[Oho! Apparently something’s stirring at Pu’u O’o, or at least there’s enough of a signal that USGS is checking it out. ]

USGS on Facebook: “The increase in gas emissions from Pu`u `O`o is certainly interesting and suggests shallow magma, but we’re not seeing deformation nor seismicity indicative of a backup.”
[…]
“We’re planning on another flight tomorrow, if weather cooperates, with a thermal camera on board.”

Q: If a new eruption at Pu’u O’o were to start, would it be considered new or part of previous one? 

USGS: We’re not really sure what we would call it at this point if Pu`u `O`o were to restart. We haven’t even had a big discussion yet about whether or not we want to call the new fissure system a “new” eruption (we’ve got passionate viewpoints on both sides).

Question posted on FB this evening: Hawaii Civil Defense just posted no movement in the lava channel. Is this true?

USGS, about 8pm HST: “There is no movement of lava in the channel. Confirmed.”

Another asked about summit inflation.

USGS: “No, there aren’t any indications of summit inflation at this point. All of the indicators are pretty flat right now — no inflation, no deflation.”

Q: [How do you determine when this event has concluded?]

USGS: We expect things would quiet down on the volcano for a while — weeks, months, perhaps years. That would be the conclusion of the event. But these events often sputter to a close, and it might be that Fissures in the system reactivate briefly before things go completely quiet. The ends of eruptions are very chaotic and subject to numerous conditions that are difficult to forecast.

Q: [More specific question about outcome of eruption on summit]

USGS: We expect the caldera will continue subsiding to some degree even after the lower East Rift Zone eruption is over…probably for a couple of months after. When it all stops, magma will return to the summit – like it has done repeatedly after collapses that followed 1925, 1955, 1960, and even after the collapse of the last caldera in the 1400-1500s. Kilauea is young and is still building itself…it will continue to do so.

[Response to several questions]

USGS: 1) The Koa`e earthquakes are a response to the downdropping of the summit. Most of those faults dip to the north, towards the caldera. We can see from satellite deformation maps that faults there are rupturing, and have been since late May. 2) We doubt that the M3 south of the summit was anything significant, given all of the other seismicity. The earthquakes are a consequence, and not a cause, of the activity we’re observing. 3) Iki is in line with other summit tiltmeters that show a leveling off of the deformation.

Since PGCam got toasted in a brushfire, USGSVolcanoes pointed to lavacam.com, a new webcam pointed towards Fissure 8. Also, as the KE cam keeps disappearing from the webcams page, here’s a direct link: https://volcanoes.usgs.gov/observatories/hvo/cams/KEcam/images/M.jpg

[Next comment was posted first thing this morning (Aug. 5) on FB, in response to “what’s going on?” type questions.]

USGS: As Tim mentions, this is kind of a waiting game. These eruptions wax and wane. But, the decrease in activity from the fissure system in addition to the flat deformation and decreased earthquakes at the summit indicates to us that magma has ceased leaving the summit storage region. We will have more analysis published in the update later this morning.

[Q: Why is this eruption different from previous, shorter LERZ eruptions? (Asked on Aug 3, when Fissure 8 was still flowing)]

USGS: Eruptions stop when the supply of eruptable magma is extinguished. This eruption is different from historic lower East Rift Zone eruptions for a few reasons. 1) there was a lava lake AND a long-lived eruption in the middle east rift prior to change in activity (two different storage regions of magma drained and have erupted from the LERZ). 2) The M 6.9 earthquake plus foreshock/aftershock sequence occurred at the start of eruption, and we believe it opened up a portion of the ERZ that was blocked, allowing magma to flow from summit.

[Q: If Hurricane Hector hit, what could storm surge do to lava? Will your summit cams be ok?]

USGS: The webcams are located in the HVO Observation Tower, so they will [hopefully] be okay. The lava delta is another story. It is somewhat unstable because it is built on unconsolidated lava fragments and sand. This loose material can easily be eroded away by surf, causing the new land to become unsupported and slump into the sea. Here is the link to summit webcams, in case anyone wants to take a quick peak, https://volcanoes.usgs.gov/…/multimedia_webcams.html

On Aug 4, before current slowdown, USGS answered another question about how “massive amount of water” from hurricane could affect lava flows:

USGS: You’ve seen the video, how the surface of the lava flow chills to form thin crusts. A lot of rain could help that process along a bit, but consider that lava has been coming out of fissure 8 at (roughly) 50 to 150 cubic meters per second (65–196 cubic yards per second). At that rate, lava will keep chugging toward the sea, even if a hurricane were to occur.

@USGSVocanoes retweeted this from (I think) a member of a UK research group that’s working on new ways to measure high SO2 emissions:

Following that Tweet back to its source led me to more Tweets by this scientist and by others doing fieldwork for various international scientific teams. It’s not just HVO that’s studying Kīlauea! So if you’re curious about some of the research being done on this eruption, go look at these Twitter channels and see what else they’re posting/retweeting: