May 29: Day of Reckoning for PGV (and LavaCam)

I’m wiped after following events of the last two nights from 3 timezones later— nothing compared to the exhaustion of Puna residents or HVO geologists, I’m sure— so today’s post is going to be less meticulous.

Today’s Eruption Summary

Sunday and Monday nights, the new monster Fissure 8 tossed fragments high in the air that carried onto houses over a mile away: clinkerly bubbly volcanic cinders (also called tephra), fine glass strands called Pele’s hair, and small volcanic glass droplets called Pele’s tears. Authorities warned people to be careful of Pele’s hair, which is basically natural fiberglass, as it can cause skin and eye irritation.

Another spate of vigorous 200-foot-tall fountaining from Fissure 8 last night sent a second fast-moving flow northeast along the edge of Sunday night’s flow, triggering more emergency evacuations and (I’m afraid, haven’t seen any tally) the loss of more homes. At 6:30am Tuesday, civil defense closed Highway 132 near the geothermal plant in anticipation that lava would reach it today. At 3:30PM, the lava did indeed begin to encroach on 132, leaving only one other road still open to Lower Puna.

Before crossing 132, 8’s northeast lava flow marched towards and into PGV property, cut off plant’s main access road, prompted staff to evacuate, and began to burn and cover over buildings and equipment. I believe sensors have been left to monitor the wells. I’m guessing a’a is a better thing to get covered by: it’s somewhat cooler than pahoehoe, and it can’t seep into cracks.

At the summit, ash eruptions and earthquakes continue. A 2am ash eruption was 15,000 feet tall, followed by a 4.5 earthquake. Light winds are sending the ash nw, towards Volcano and Pahala. There’s a meeting at Pahala tonight to discuss vog and ashfall, which is going to be an ongoing problem for these communities however long this eruptive phase lasts. 

At night, the webcam is showing incandescent blocks flung out onto the rim of Halema’uma’u Crater, but we don’t know how big or how many because it’s unsafe for scientists to approach. However, they’re installing a new thermal cam soon that should help them see the blocks. (Source: 11AM conference call) 

Time for today’s roundup of USGS bulletins and info, relevant posts by geologists, images and videos, local news reports, and the eruption through the eyes of social media.

Continue reading May 29: Day of Reckoning for PGV (and LavaCam)

Video Clips: Pāhoehoe vs A’a (What’s the Difference?)

If you’ve followed this blog at all, you’ve come across the terms “pāhoehoe” and “a’a.” They’re Hawaiian words borrowed by volcanologists as technical terms for different types of lava. How can you tell which is which?

When I visited in 1986, the joke was that “a’a” is the noise you make when you walk on it, because it’s prickly, and “pāhoehoe” is the smooth stuff. But that’s oversimplified, and it confused me. Some of the old pāhoehoe flows we hiked on near Mauna Ulu seemed pretty bumpy to me.

Pāhoehoe lava is runny, faster-moving, and often described as “ropey.” It’s pretty obvious when it’s spilling into a crater or running swiftly in a river. Sometimes it has ripple marks. At other times, the leading edge slows down and turns blobby. Here’s an excellent USGS video of a pahoehoe front in night and day, May 24-25:

Pāhoehoe moves forward by inflating lobes of lava with fresh new lava from within.

Then there’s a’a lava: a crumbly, chunky mass of what looks like a heap of rocks and gravel and dirt, except it’s red-hot under the outer skin. It moves like a horizontal landslide in slow motion, bulldozing everything in its path:

It advances mostly by chunks tumbling forward off the front.

A’a is usually quite slow. You can outwalk it. In fact, you’d usually have time to pack a small suitcase if it showed up at the end of your street. Whereas when pāhoehoe flows downhill or becomes “channelized,” making itself a smooth chute, you can’t outrun it:

Both kind of lava make crinkly noises, but I think of a’a as “clinkity clankity” lava, whereas pāhoehoe tends to slither.

So now you’ll know how to explain it the next time someone asks, “What’s the difference between pāhoehoe and a’a?”

May 26: Lava Turns Towards PGV

Puna residents watch with a sinking feeling of “I told you so” as a ponderous a’a flow crossed Pahoa Pohoiki Road slightly north of the geothermal plant, inching towards it. Officials think they’ve got the wells quenched  (I notice they quietly dropped the idea of plugging them), and that they’re safe.

Hawaii County photo looking south across Pohoiki Road, geothermal plant bottom left. Photo not timestamped but probably around noon. “Fissures 7 and 21 are feeding an ‘a’ā flow that has advanced to the northeast and this afternoon crossed Pahoa Pohoiki Road onto PGV property, USGS reported.”

Meanwhile, Fissure 7 is causing trouble in all directions; its lava pond has sent another flow “cascading into Pawaii crater” (6:15pm).  Looking at the map, I’m betting that crater is an old vent from a previous fissure eruption just like this one. In addition to fluid/runny pahoehoe flows, some of the longer flows are a’a.

The summit has also been busy today, with three ash explosions reaching the ~10,000 foot height between midnight and dawn, and some reaching “as high as 12-13K‘ [above sea level]” this morning. Reminder: Kilauea is 4009 feet above sea level (asl).

Moving on. I’ve gotten in the habit of checking the Lower East Rift Zone webcam last thing before I post:

USGS webcam of LERZ. Grabbed just before midnight, May 26. Is that a lava flow coming towards the camera?

Next image on the LERZ webcam.

I do believe it is. Has that lava pond broken loose?

Lava tally as of Saturday morning: 41 houses, 82 structures total. A further 37 homes isolated by lava crossing roads. Lava has covered 3.7 square miles/2372 acres so far.

Here’s the usual roundup of the day’s eruption news, astonishing views, and geeky info by geologists:

Continue reading May 26: Lava Turns Towards PGV

May 19: Rivers of Lava, Fissure 20 Races for Ocean

HNN posted a brief video recap of some of the incredible lava river/fountains last night, identifying it as Lanipuna Gardens (I wasn’t sure.)

Today, Honolulu Civil Beat just left the camera on, and the lava just keeps coming.

Yep, Rusty the Rooster is still trying to tell us it’s morning.

However, despite using a still from dawn Friday morning showing Fissure 17 at its most glorious, its cinder cone is now much higher than it is.

Late Saturday, HCB Livestream screencap. Fissure 17 dwarfed by its cinder cone now.

Friday night it was incredibly spectacular, but by Saturday the group of combined fountains at Fissure 20 had taken the spotlight, sending vast amounts of Pahoehoe down to the ocean. That said, 17 continued be loud; it’s the one that sounds like a thundering detonation or jet engine in short, loud bursts.

May 18: “Fresher, Hotter” Magma Arrives, HUGE Fountains Begin

Thursday May 18: Fissure eruptions went into overdrive [Good article from Star-Advertiser] as “fresher, hotter magma” (Janet Babb, USGS geologist) arrived from summit. Fissure 20 released a lava flow down toward coast, crossed Pohoiki Road, and isolated about 40 houses. Four cut-off residents were airlifted out.

Here’s an archived livestream by Honolulu Civil Beat starting before dawn Friday morning:

Check out daylight screencap from late in the broadcast to get sense of scale: note house.

The USGS also posted a brief video clip of Fissure 17 in its Kilauea-Iki-like glory:

May 19, Friday afternoon, a new livestream started from same channel  as before ( They streamed through most of the night, occasionally shifting view from large fountain behind house (Fissure 17) to lava flow and a group of lava fountains building spatter ramparts (Fissure 20 merged with others) upslope to the right.

Friday, HawaiiNewsNow’s Milika Lincoln filmed same area in late morning from nearby location, near Lanipuni Gardens: fissure 17 fountain was now 500 feet tall. There seems to be a crater (pu’u) forming to the right of 17’s fountain. She also interviewed a resident who saw Fissure 17 form— as they talk, it roars. After dark, her crew’s footage is absolutely spectacular. (She’s calling it 19— either I’m mistaken about which one she’s watching, or she is.)

You can really tell this is hotter, fresher, more voluminous lava that drained from Pu’u O’o, as opposed to the old, stiffer, cooler lava that erupted from fissures in Leilani Estates the first two weeks of this eruption.

“Ground deformation is continuing with increased seismicity” in Lower East Rift Zone, and USGS warn lava inundation below them is possible, and that more fissures could still open uprift or downrift. “All fissures are actively spattering or actively degassing.” 40 structures lost.

Dec 2011: Lava from Pu’u O’o Entering Ocean

Video by Bryan Lowry of in 2011.

Back when Pu’u O’o was healthy, it sent lava flows south down the flanks of Kilauea to the ocean, mostly away from populated areas (although unfortunately it did take out the community of Kalapana plus the half-built Royal Gardens Subdivision). See HVO’s photo history of Pu’u O’o from 1983 to the present.