August 27: After Fire, Flood (Hurricane Lane)

August 22, 2018. USGS: “Parts of Kīlauea’s caldera floor are now a jumble of down-dropped blocks and surface cracks. HVO field crews carefully hiked along Crater Rim Drive yesterday to verify the locations of USGS benchmarks (lower left), which will be used for additional geophysical work that will help document the recent summit changes. The view is to the northwest with one flank of Mauna Loa visible in the distance (upper right).” (Full-sized)
Weekly Eruption Summary

After a busy few months, Kilauea continues to rest with only a pilot light on, so to speak. This week’s big news was that Hurricane Lane passed offshore of the Big Island on Thursday through Saturday, causing extensive flash flooding. But there’s still a little news to report on the dying (?) embers of Kilauea’s 2018 eruption.

On Friday morning, the Hawaii County Fire Department observed a small lava pond still visible deep in Fissure 8’s cone. For most of the week, there was no visible activity apart from a few small jets deep in the cone throwing weak spatter on Monday morning:

August 20, 2018. USGS: “This morning, USGS scientists flying over fissure 8 noticed a change in the vent from yesterday. Gas jets were throwing spatter—fragments of glassy lava (light gray deposits)—from small incandescent areas deep within the cone. This activity is an indication that the lower East Rift Zone eruption may be paused rather than pau (over).” (Full-sized)

The sputtery jets proved to be temporary:

August 21, 2018. USGS: “Southward facing aerial view of the fissure 8 cone. The two small areas of incandescence, gas jetting, and spatter from yesterday photograph appeared crusted over today.” (Full-sized)

Down at the ocean at Kapoho, there were a few weak dribbles of lava continuing to drain out of the delta at the beginning of the week:

August 20, 2018. USGS photo of residual lava entering ocean, posted on their facebook page here.

Sulfur dioxide emissions continue to be very low both at the summit and the coast. In fact, on Tuesday, they dropped too low in the Lower East Rift Zone for instruments to measure, although not too low for highly-sensitive human noses to detect.

Video from August 17 posted on the 20th— full-sized version here.

Heavy rain from Hurricane Lane on Friday and Saturday put a hold on USGS overflights and field observations and knocked out a few sensors on the east side of the island. But Kilauea’s extensive sensor network means there was no gap in volcano monitoring, and field crews were on call just in case.

The hurricane had no impact on the volcano apart from heavy rainfall hitting hot rocks and turning to steam in Pu’u O’o’s crater and on the not-yet-cooled lava flows of the LERZ. There were some reports of local white-out conditions from this steam. Rain may also have triggered a few rockfalls at the summit.

The other big Kilauea news this week is that Hawaii Volcanoes National Park has set a target reopening date for September 22, aiming to reopen at least the Visitor Center and (they hope) some kind of viewing area from which visitors will be able to see the new, larger Halema’uma’u Crater. They’re also hoping to open Volcano House, but they need to check the stability of the cliffs on which it stands.

USGS Volcano Watch

Whoops! I think I missed last week’s edition. This is Hawaiian Volcano Observatory’s weekly column with photos and in-depth information on some aspect of Kilauea.

From Other Scientists
From Local News Media
Mick Kalber Overflight

Okay, this isn’t volcano-related, but impressive aerial footage of flooding around Hilo on Saturday including Wailuku River and Rainbow Falls (see Bruce Omori’s slideshow of same flight).

USGS Q&As on Social Media

Q (Saturday, Aug 25): [If emissions are low, why is the smell of rotten eggs so bad?]

Allan Lowe on FB: That smell is hydrogen sulfide. Humans are sensitive to its smell in very, very small quantities. It is created when magma or lava of a certain temperature mixes with water, which we’ve had a ton of thanks to Hurricane Lane.

Charles Gregory on FB: Christine, just to be on the safe side, give HVO a call and ask them about the rotten eggs smell. Without any seismic activity, It seems likely that Allan’s suggestion about groundwater is correct, but if new ground cracking is occurring in the forest near you, that smell could be the first sign of it. Can’t hurt to double-check with the experts.

USGS: Alan and Charles are both correct – the smell is probably H2S, and it is detectable at a few parts per billion (a very small amount). You may contact HVO at the askhvo@usgs.gov email or the Observatory phone (808-967-7328). Email may be faster, as many of the staff are working from home.

[followup] In south-southwesterly winds even the smallest amount of H2S is sent into neighborhoods and towns to the north of PuuOo and the summit. Because the gas is so detectible by the nose we are getting a lot of reports of people smelling it. When the winds shift to trades the smell goes away…then when it shifts again to more southerly, it will become apparent again.

Q: [Impact of hurricane on volcano?]

USGS: The hurricane has had no significant effect on the eruption. It may be cooling any hot material left on the surface, and it will almost certainly remobilize the ash and loose material in and around the summit crater, but that is all wind and water processes, not eruptive. You can check out this 2014 article on the topic to see more commentary on hurricane vs. volcano:https://www.smithsonianmag.com/…/what-happens-when…/

Q: [Could hurricane cause new lava delta to collapse, triggering a tsunami?]

USGS: Lava deltas are unstable, but there is no danger of collapses at Kilauea’s new delta forming a tsunami. The area of the delta that could be affected by a collapse is relatively small, and collapse effects (if there are any) would be local.
You can read more about the hazards [of lava delta collapse] at https://volcanoes.usgs.gov/…/hvo/hawaii_ocean_entry.html

New satellite radar images of Kapoho / Lower East Rift Zone area, April and August:

Q: [Why aren’t we getting more reports about Kilauea activity? The public should be informed just as much as in April-mid July.]

USGS: There has been less reporting because there is nothing to report. Kilauea has been quiet seismically, lava has ceased to erupt in the East Rift Zone and there has been no summit activity other than rockfalls from gravitationally unstable material on the edges of the crater. The volcano is still being closely monitored, however, and the USGS would report immediately on any renewed activity.

A Look Back

From Th. Tunsch on Twitter: “Changes in the Kilauea caldera from May 14 to July 19, 2018”