June 18: USGS Kilauea Conference Call

BigIslandVideoNews posted an abridged version of today’s USGS Media Conference Call:

Here’s the full unabridged audio recording.  Below, I take notes/paraphrase, for anyone who’s especially interested in the nitty gritty of what’s going on with the volcano.

June 18 USGS 11AM Media Conference Call

Host: Leslie Gordon, USGS Public Affairs
Lis Westby Geologist USGS*
Brian Shiro Seismologist USGS/HVO
John Bravender Meteorologist NWS
Becky Schwab Hawaii Volcanoes NPS

*(Rotating in from Cascades Volcano Observatory; she’s been helping with USGS social media since eruption started)

[WARNING: paraphrase/notes are my own; it’s possible I may mishear something.]

Summit update (Brian Shiro)

Situation at summit over past day similar to past couple of weeks. “We had a swarm of earthquakes overnight that led to a large collapse/explosion event” at 6:12am. Moment Magnitude 5.3, typical of events in recent days. Some felt reports, but not felt widely, as with past events. Slumping/faulting into Halema’uma’u continues. Earthquakes continue; Volcano residents continue to feel them. We’re monitoring closely as conditions allow.

[Added after Liz: morning’s even at summit produced “very small, minor plume that went no more than 500 meters above the ground.” So height < 4000 feet a.s.l., one of the smallest ones yet.

LERZ Update (Liz Westby)

Activity focused on Fissure 8. Fountains 150-180ft overnight measured by HVO field crews. Fissure 16 & 18 oozing lava. Some incandescence from Fissure 6 overnight, mild spattering observed during morning overflight. Essentially, flow field remaining stable. New fissures/flow map just posted to HVO webpage. Lava now covering 9.4 square miles. Ocean entry: lava continues to enter ocean on southern part of broad front near Vacationland. Lava delta 360 acres.

John Bravender (Meteorologist, NWS)

“Dry and stable weather pattern right now.” Limited cloud cover, especially n. sections of Big Island. Passing showers but not much rainfall amounts.  Winds very light, allowing for some turning and variations. Continues through tomorrow. By Tues night, into Wesnesday, flow may turn easterly or southeasterly which could cause affect Pahoa, raising concerns about volcanic emissions reaching different areas: Pahoa, etc. Higher winds out of north, so larger plumes might get blown offshore.

Becky Schwab (Hawaii Volcanoes NP)

Day 39 of park closure. Most part closed, Kohuko unit open Wednesday-Sunday, 9am-3pm. Park rangers in Discovery Center down in Hilo 9-4pm Tues-Sat answering public’s questions.

Question & Answer Session

Q: Explain summit slumping? How long will it last?

Brian:  “So the magma chamber underneath Halema’uma’u has been undergoing changes since this event all began in late April, early May. We think that the shallowmost [sic] portion of that chamber may have evacuated partially. And this is leading to some of the conditions that result in the slumping.” Gravitational instability, exacerbated by earthquakes. Causes sides of Halema’uma’u to break and fall inward. Some of it happens during the event. Some of it happens more slowly in slumps on a continuous basis. New GPS stations in area monitoring [straight?] events as well as continuous motion.  Drone flights every few days “to capture what it looks like as well.”

Q: How far does new delta extend out from original Kapoho shoreline, and how deep is the water at new shoreline?

Brian Shiro: (We’re looking into numbers) The coastal offshore area there is very shallow, unlike south flank of Kilauea where it’s deep. Therefore we think that the delta being built is going to be more stable than the deltas that have been built off the south flank of Kilauea from the Pu’u O’o flows in the past. So that’s a reflection of the fact that the slope is very shallow. It’s also very shallow offshore.[…]

Liz Westby: There’s a nice interactive map put out by Hawaii County Civil Defense, and that allows you to take measurements. Just did it from Kapoho to furthest point: 0.65 miles. As mentioned earlier, most of the active entry is on the southern portion at Vacationland and points south; this is just a measurement of Kapoho Bay [former shoreline] towards the east.

[These reporters are running out of questions. That would not be a problem if I were there! I still want to understand the deformation data  better during these subsurface explosion cycles.]