The Lower East Rift Zone eruption continues as per usual. USGS reported during today’s morning overflight that “the channel was incandescent its entire length from vent to ocean entry.” There’s a main ocean entry a few hundred meters NE of the southern flow border with smaller pahoehoe flows on either side. The southern margin doesn’t seem to have advanced much from yesterday.
No other fissures are active, and I already covered yesterday’s 4:33 HST collapse event. I’m betting the next one will be after dark.
Janet Babb, Kīlauea Update: Good afternoon, everyone.
On the Lower East Rift Zone, Fissure 8 is still active. It continues to erupt lava into the perched channel that extends down on the west side of Kapoho Crater and feeds lava into the ocean. This morning, the main ocean entry was a little bit west of Ahalanui, with the flow margin about 500 meters, or 0.3 mile, from the Pohoiki boat ramp. There’s still some weak ocean entry points to the north of this main entry over near the Kapoho Bay lobe of lava where there were some weak, wispy plumes there. The flow front along the ocean, along the coast is still about 6 kilometers wide or 3.7 miles wide. On the Lower East Rift Zone, the sulfur dioxide emissions remain high, and the ocean entry hazards include the laze plume, as well as the possible hydrovolcanic explosions, what we referred to on Monday as “littoral explosions.” Hydrovolcanic is a little more intuitive word to explain the lava-seawater interaction.
Up at the summit, as we speak earthquakes are occurring at a rate of about 25-30 per hour as the volcano builds up to the next collapse event [this phonecall at 1 pm, collapse came at 4:33 pm.] The previous collapse event weas at 1:28 am July 18, so it’s been about 36 hours. We are within that time interval where we typically see these collapses occur. At the summit, the sulfur dioxide emissions are low. We’ll be posting some new photos and a new map shortly after this media call. That’s all.
As per usual. Fissure 8 continues to feed the lava channel down to the ocean, where the southern margin of the flow was 500 m from Isaac Hale Park this morning. Lava levels in the channel this morning were low, with the previous collapse event coming at 1:28 am the day before.
Today’s summit collapse event occurred at 4:33 pm.
Q: [Is Cape Kumakahi still the easternmost point of the island?] USGS: The area off Kapoho has a paltry supply of lava now – unless significant lava returns, the eastward advancement may cease.
Q: [Has there been any change in temperature of lava, now that it’s crusting over and/or not a fluid channel all the way to the ocean? Any sign eruption is ending?] USGS: No, the temperature remains the same. Other factors are probably responsible for the crusting – blockages, flow velocity, precipitation, etc. Sometimes the channels remain fluid, and sometimes the surface can crust over – but that doesn’t mean there isn’t lava moving beneath the crust… No, no signs that the eruption is ending yet.
Q: [Someone asking about webcams and livestreams] USGS: We weren’t able to adjust the bandwidth on the cam from HVO, but we did add the stream from the northeast caldera, which uses a different (and still challenged) connection.
Q: [Cinder cone is 120 feet now? Was 180; has it collapsed?] USGS: Some settling has occurred, and some of the more precarious bits have probably fallen in or down the slopes. [Same basic question, different day] USGS: Yes it has succumbed to thermal erosion, collapse, and settling. There have been no sustained fountains depositing material on its outer slopes for several weeks, so there has been no additional accumulation of tephra.
Vladimir Vysotsky on FB: USGS Volcanoes: you keep characterizing this as a “perched channel”. I wonder if that is how lava tubes form – a channel builds the foundation and walls around itself, then crusts over while still flowing inside, and eventually forms a tube when the lava finally drains. Is that a correct assumption?
USGS Volcanoes: That is a very accurate description of lava tube formation! ][…] Hereʻs a video from Hawai’i Volcanoes National Park describing what you d[id] with video footage to accompany for visual reference. https://www.nps.gov/media/video/view.htm...
Q: [Is Fissure 8 how Diamond Head formed?] USGS: – Diamond Head is a tuff cone that erupted through water. It is also considered “rejuvenation stage” volcanism. The eruption that formed it occurred after the Koʻolau Volcano (from where it erupted) had been dormant for about 2 million years! http://volcano.oregonstate.edu/post-erosional-rejuvenation
Q: [How long will this go? How will it end? Does a lava flow normally start slowing down and then stop?] USGS: This could go on for any number of days, honestly. Typically these things don’t just turn off and stay turned off. We expect that activity in Fissure 8 will wane, then stop and start again (perhaps at other fissures). However, the eruption won’t stop all together until the pressure driving the magma out of the ground has been relieved.
Q: [How deep is lava channel?] USGS: We have tried to calculate depths based upon lava-flow observations within the channel and known depths of dormant channels on other locations in the Hawaiian islands. The channel is meters in depth, but likely not more than 10. Depth varies throughout its length as well.
[In discussion that Fissure 8 is not a volcano— it’s a vent on Kilauea’s flank just like Puʻu ʻŌʻō was, with magma being piped down from Kīlauea’s magma storage system— someone brought up Lō‘ihi, which IS a new volcano (or seamount) off SE coast of Big Island, still underwater.]
Q: [Is the summit caldera sitting on the magma chamber?] USGS: The subsidence area within the caldera essentially overlies the area of the shallow magma storage region that fed the lava lake in Halemaʻumaʻu. So, yes. Q: [Could the floor collapse into the chamber? What would happen then?] USGS: Technically speaking, the floor, and everything that was between it and the top of the chamber, is collapsing into it. Youʻre seeing the outcome – pressure drops and collapse events that manifest as M5.3 earthquakes.
Here’s a transcript of this week’s presentation from HVO Deputy-Scientist-in-Charge Steve Brantley at the Tuesday Pahoa Community Meeting.
I’m going to start with a broad overview of the eruption so far. We’re 80 days into the eruption [since the floor dropped on Puʻu ʻŌʻō, I think] about now, so I want to provide a little bit of context, in terms of similar activity or un-similar activity in the past 200 years. And then we’ll do a quick summary of what’s happened in the past week.
Fissure 8 surged after last night’s summit collapse and sent brief-lived overflows towards Nohea Street and on both sides of the channel further down. Civil Defense reported an unspecified number of structures lost; Janet Snyder of the Mayor’s office said one in the mandatory evacuation zone of Leilani Estates.
Other fissures remain quiet.
Past Kapoho Crater, a pulse of a’a made its way to the ocean, overriding the existing channelized flow on the south side of the delta. Ooze-outs continue here and there along the edge of the delta.
Kilauea’s double eruption continues as usual. Fissure 8’s lava river is still sending lava mostly to the southern ocean entry near Ahalanui, following the diverted channel on the west side of Kapoho Crater. The southern margin of the lava flow along the coast has slowed its southward advance, possibly giving Pohoiki/Isaac Hale Park a respite. At 7pm HST, HVO said it was “around half a mile away.”
The tiny island that formed Friday is now a tiny peninsula, joined to shore by a neck of lava or possibly just black sand. Lava continues to ooze into the ocean here and there along the broad front of 6 km (3.7mi) lava delta. Recent HVO Kilauea status alerts have warned that this delta has built out 0.5 miles from the former coastline, and is resting on “unconsolidated lava fragments and sand,” which can give way.
Following this morning’s 3:26 am collapse event (M5.2) at Kilauea’s summit, a pulse of lava came down the rift zone to Fissure 8. This caused an early-morning, temporary overflow to the ESE which did not extend beyond the boundaries of earlier flows. (This spillover was very visible during a 6:30am @hotseathawaii livestream overflight). No other vents show any activity.
The Lower East Rift Zone eruption has settled back into a routine. Unfortunately, that routine includes the far end of Fissure 8’s lava flow crawling south along the coast, eating landmarks in its path. Isaac Hale Park/Pohoiki boat ramp (see flow map) is next in line. The morning USGS overflight reported that the flow front was about 1km away.
Friday evening, July 13, 2018, 6:00 pm – Kilauea's east rift zone overflight: Lava continues to pour into the sea at…
Fissure 8 continues to erupt into its perched channel, with its volume surging after yesterday’s 7:08pm summit collapse (Mag 5.3) and returning to lower levels by morning. That pulse caused a brief overflow on the east/southeast of the channel a short way downstream from the vent, but it stayed on the apron of previous flows.
The channelized a’a flow west of Kapoho Crater continues to be the main conduit to the ocean and to the active flow expanding southwards along the shore. North of this, lava continues to “ooze out” at various points along the June-early July flow front, whose length now totals 6km (3.7 miles).
While there’s no sign of activity at any fissures besides 8, the tiny island that popped up just offshore of Kapoho yesterday is still there for now.
Fissure 8’s lava flow has settled into its new course, turning right just before Kapoho Cone and proceeding south-southeast to the ocean in a strong channelized a’a flow. Some lava, apparently following the earlier paths (lava tubes, maybe?) to the sea, is still squeezing out of the broad 6km (3.7) mile lava delta to the north of the new ocean entry.
A fascinating footnote: while the northern “ooze-outs” are weakening, a tiny lava island popped up just offshore of them last night, and it is itself oozing lava:
Today’s summit collapse occurred at 7:06pm HST, with the energy equivalent of a 5.3 earthquake, as usual. HVO is setting up a new livestream from Volcano House, but it’s not fully operational yet, so we made do with the ailing HVO webcam today (video clip).
Kīlauea Message Fri, 13 Jul 2018 21:53:34 HST: Following the 19:08 HST summit collapse explosion today there was an increase in activity from fissure 8 resulting in channel overflows on the south side of the flow near the vent.
Also, we’ve got a new view of ever-expanding Halema’uma’u Crater in Kilauea’s summit caldera this morning:
I couldn’t find a comparable aerial photo with the observatory and Jaggar in shot, but this 2009 photo of Halema’uma’u is facing in approximately the same direction. (Look for Crater Rim Rd behind the crater on the left, and note the parking lot obscured by the lava lake’s plume in 2009— lava lake, parking lot, and part of that road collapsed into the crater in June.)
Quite a lot happened today in the LERZ. Fissure 8 started overflowing again about 8:30-9am this morning. Unfortunately, some spillouts on the north side extended past the edges of previous flows, destroying three more homes in Leilani Estates, two on Luana St, one on Nohea.
Another blockage just west of Kapoho Crater last night diverted much of the main lava channel around the west side of the crater’s cone, rejoining the main flow field on the other side. It created a channelized a’a flow which skirted the southern edge of the existing lava field, and was a quarter mile from the coast and Ahalanui Warm Pond by noon. [Update 10pm HST: I’m seeing several unconfirmed reports on social media that it and Kua O Ka La Charter School were taken by lava late Wednesday afternoon or early evening.]
However, some lava is still being supplied to earlier ocean entry areas, either by still-molten lava that’s permeated the lava delta, or by a lesser supply of new lava following the old route around Kapoho Crater. This lava is working on building a point (it’s still not the easternmost point of the island, although the angle of the left-hand photo makes it appear so):
New lava channel on south side of existing channel and wraps around west side of Kapoho cone, lava within 2,000 ft of the coast at Ahalanui Beach Park. Summit collapse event occurred at 5:46 AM HST.https://t.co/7sDZqcOJ5spic.twitter.com/kkt3wI7XAy
Interestingly, today’s tardy summit collapse at 5:46am (M5.3 as usual) seems to have had some effect upon Fissure 8. There’s been speculation that might be occurring, but it wasn’t confirmed until now. According to the HVO update: “The collapse/explosive event this morning was followed by an increase in lava from the fissure 8 vent which has produced small overflows from the upper channel that are threatening a few homes on Nohea and Luana streets.”
Fissure 22 continues to sputter quietly and intermittently, so the sluggish flow it was emitting a week or so ago has cooled.
Transcript of Steve Brantley’s Tuesday evening presentation at the weekly community meeting, July 10, 2018.
Steve Brantley (HVO/USGS): Well, good evening. Thank you for turning out. I worked really hard this afternoon to prepare my very best presentation for you tonight, and lo and behold, somehow it didn’t end up on my jump drive. So for that, I apologize. And what I’ll do is basically recount the presentation, but you’ll have to— we can refer to the map up here.
So the overall picture is that the activity at Fissure 8 has not fundamentally changed. A high rate of lava is still being erupted, and we really haven’t noticed a change in that rate. At the summit, the volcano continues to subside very slowly over time, and periodically— now about once every 30 hours, or almost every day— the ground drops as much as two and a half meters or so in each drop, and results in a ground shaking that’s equivalent to about a magnitude 5 event.