July 5: USGS Media Conference Call

Between computer troubles (fixed now!) and that all-important Volcano Village meeting last Thursday evening, I missed the July 5 11am USGS media conference call. Here’s the archived audio file.

It was short, but for completeness’ sake, here’s a transcript.

[Note: Posted July 9, 3.30pm HST, backdated to keep it in correct order chronologically.]

Kyle Anderson, USGS Geophysicist: I’ll just give a brief overview of the ongoing state of the eruption with a focus on the summit. So magma continues to leave the summit at a high rate towards the East Rift Zone, and the Lower East Rift Zone eruption continues.

Deflation of the summit magma reservoir is causing subsidence to the surrounding rock, and this is occurring constantly. But on top of this, we have episodic collapse events, and these are continuing. These events are associated with inward slumping of the rim and the walls of Halema’uma’u Crater, and also a large portion of the Kilauea Caldera floor. Recent events have really emitted only very weak dust plumes into the atmosphere. The most recent event occurred yesterday, July 4 at 10:19 am local time. And the energy released by this event was equivalent to a magnitude 5.3 earthquake. Following the recent pattern that we’ve seen, seismicity dropped abruptly after that event, but has gradually risen since then.

Emissions of sulfur dioxide remain very low, and in fact they’re now comparable to the levels last seen before the occurrence of the summit lava lake in 2008. And I’ll just finally add that the total volume change of the crater, the caldera, now exceeds 400 million cubic meters. That’s as of June 30, and it’s been increasing at a rate of a bit more than 10 million cubic meters every day. The elevation of the bottom of the crater—  we don’t have a good number on that since June 21st— but at that time it was just under 700 meters above sea level. Before current activity, the bottom of the crater floor, excluding the lava lake vent itself, was about 1,030 meters above sea level. So that’s a decrease of more than 300 meters, about 1000 feet. However, again, those numbers are from June 21st, so they may be a bit different now.  And that’s all the summary I have, but I’m happy to take questions.

Bob Burke, NWS:   [breezy tradewinds and shower activity more or less into early next week.]

Questions and Answers

Q: Can we expect to see more intense thunderstorms like last Monday when rising heat from lava flow boosted storm activity?

Bob: Right now we’re not anticipating a similar event to occur. The air mass is going to be a bit more stable than it was the other day when we had the thunderstorm develop in the vicinity of Leilani Estates. We’re pretty much embedded in a decent tradewind flow this time around whereas the winds were a bit lighter the other day when we had that event. So at the current time we’re not anticipating a repeat of a stationary thunderstorm in that vicinity at this time. We can never say it’s not out of the question, but again, since we’re in a tradewind environment, and the airmass would be a bit more stability over the area. So at this time we’re not anticipating a repeat of that. But it does look like again, there could be a second area of moisture coming in late Friday night into Saturday; there could be some moderate showers around the island, so, particularly on the windward side.

[technical question about usefulness of launching weather balloons near LERZ vs Hilo.]

[Questions for National Park Service, whose rep took July 5 off, and Civil Defense, who isn’t part of this call.]

Q: How many acres is the lava delta?

Paul: I believe it’s 555 acres.

Q: How much land is created per day; per week?

Kyle: I don’t have those numbers. It’s something we could look into.

Q: Does Fissure 8 cinder cone have a name?

Kyle: As of now, it’s still just Fissure 8.

Q: You said amount of magma coming from the summit is 400 million cubic meters [not quite]. How do you calculate that? 

Kyle: Yeah, that’s a great question. So the total volume in the caldera over the course of this eruption is 400 million cubic meters. So that volume change over a day is about a little over ten million cubic meters averaged out from late May, early June. That’s the volume change of rock in the caldera. So it’s not exactly the same rate as the rate of magma evacuation from the summit. We think that to first order they’re probably similar. Most of the loss is rock slumping down to replace magma that’s evacuated towards the East Rift Zone.

We measure that using Unmanned Aerial Vehicles at the summit, predominantly. We’ve done some work with helicopters too, but these are mostly UAVs, and what they do is they fly over the summit in a regular pattern. These are flights that are conducted with the permission of the Park Service, and because the park is closed.  They fly in a pattern over the summit, and take many, many photographs, and they go back and they stitch them all together, and they’re actually able to build an elevation model. And so what we do then is we compare elevation models from different times and look for changes. And that’s where that total volume change comes from and our numbers on the rate of volume change which over the time period over which we had measurements was actually pretty constant. And again I think it was 12 to 13  million cubic meters per day.

Because of winds at the summit, those UAVs are limited. They don’t fly very well in higher winds. So we haven’t had many good numbers since June 21. We got a partial estimate on June 30, and it looked consistent with that rate, probably continuing at about the same rate as before, but we haven’t had as many solid numbers recently as we might’ve liked.