A Christmas eruption

A fumarole near the rim of the pre-2018 Kilauea’s Halema’uma’u Crater, covered by a thick carpet of Pele’s hair produced by the lava lake. Moisture emitted by the fumaroles collects as tiny water droplets on the fine hairs, resembling a thin dusting of snow, photographed here, on May 28, 2017. (Source: Hawaiian Volcano Observatory / USGS)

Kilauea has become a different volcano. For 30 years, the summit was a passive participant in the seemingly ever-lasting Pu’u’O’o eruption. But nothing volcanic lasts forever, and 2018 was the year that proved this. A blockage near (or in) Pu’u’O’o caused the pressure in the rift to increase, the east rift gave way, and magma began to migrate eastward. Although no eruption happened at the summit, its subsequent collapse showed that the summit was an active contributor. We now have an entirely different volcano, and are lost as to what the future will bring.

But it can be hard to remember the past. Even the everlasting eruption had a beginning. Go back to before its beginning (and now we are talking 50 years ago), and you’ll discover a time when the summit erupted whenever it felt the need to release a bit of pressure. These were mini eruptions (compared to Puna 2018) but impressive nonetheless, and they happened in areas which now seem tranquil. One of these mini-events was the Christmas eruption of 1965. It is described in detail in an HVO report from where the following is taken.

With the 20:20 vision of hindsight, the event had really started in July with the onset of inflation inside Kilauea crater, just east of Halema’uma’u. (Remember Halema’uma’u?) Tremor began with little warning in the evening of 24 December, at 7:30pm. There was no time to prepare: the eruption itself began just two hours later. In those days, Kilauea could rival Hekla in speed of events, with barely an hour between the first felt earthquake and lava fountains appearing. At 9:30pm, a red glow showed that fountaining had begun, near Aloi crater, one of the craters along the Chain of Craters (it no loner exists). Observing the eruption gave some trouble to the Volcano Observatory observers. As HVO wrote ‘The observers rushed eastward along the Chain of Craters Road toward Aloi Crater, but were stopped about 500 feet west of the crater by dense clouds of sulfurous fumes and by ever-widening cracks in the road.‘ The observers could hear the eruption intensify, but not see it – until after 30 minutes a new crack opened and lava ejecta began to fall down less than 30 meters from where the observers were, convenient for the task at hand but not entirely safe. A retreat was in order, to ensure that the observers would not enter history as active participants.

The eruption declined after that, and by the time the observers finally managed to reach Aloi crater they could see the vents in the crater floor but the eruption there was nearly over. HVO wrote ‘The thin, continuous skin of lava that plastered the walls of the crater to a height of about 40 feet above its floor clearly indicated that much of the newly erupted lava had drained away before the observation parties were able to obtain a clear view of the crater‘. Kilauea had beaten the observers and managed to begin and finish an eruption unobserved, within 10 kilometers of the Observatory. The eruption continued in the forest to the east, but now rain and drizzle prevented observations. A final glow was seen at 4am, and the eruption ended at 4:10am on Christmas day. The whole event took place during the night and it was apparently not recorded in photos. The total lava output was less than 0.001 km3. This was a true mini-eruption, 20 times smaller than the one that happened in March 1965.

But the side effects were not minor. Cracks had opened over an 8 mile length, from the Kau desert to Kane Nui o Hamo. The Chain or Craters road was heavily damaged and became impassable. The width across the cracks was 1 meter. The cracking had occured during the eruption, and was largely complete by 4am. The summit had also been affected, and showed collapse, centred at the region where the inflation had been centred. The collapse was called ‘unprecedented’ at the time – in 2018 it would have been considered rather minor! But it was not only a collapse: tilt measurements showed that part of the south flank had moved seaward.

Hilani road

Earthquake activity had started two hours before the eruption, But it didn’t stop when the eruption ended. Unlike the eruption of 2018, the quaking continued to intensify, and remained high until 2pm on Christmas day. After that it decayed rapidly but it did not fully finish until December 31.

So what happened? Part of it was normal volcanic behaviour. Magma in the summit became over-pressured and took the easiest way out. That involved the rift zone. At that time, the path to the east rift zone was blocked, and eruptions happened in the rift close to the summit. Just like in 2018, the rift here must already have been close to failing. The intrusion pushed it over the edge, but instead of slipping in a single large earthquake, it gave way in a series of smaller shifts. The southern flank of the mountain shifted towards the sea. This caused the extensive cracking, which was seen over a much longer range than where the lava appeared. One may wonder whether the eruption caused the rift failure, or whether the rift failure opened up a magma path.

The eruption was brief and the rift failure had no immediate consequences. Previous eruptions had also been in the same rift region (slightly further east) and this fitted into a pattern. There were more minor eruptions in the following years, and a major eruption occurred in Halema’uma’u in 1967. But on May 24, 1969, the Mauna Ulu eruption began, which lasted for 2200 days (and also destroyed Aloi crater). This was the first phase of the Kilauea shield eruptions that over 50 years came to destroy so much of the southern coast. What caused this change in behaviour? Perhaps the opening of the rift on Christmas 1965 was part of the re-opening of the pathway, which had been closed since Kapoho 1960. And over the years, the re-opening continued opening eastward, from Aloi to Mauna Uu to Pu’u’O’o and onwards: this Christmas 53 years ago was a small step on the road to Leilani.

And also on the road to its end. The 2018 Leilani eruption ended with an earthquake in the area of the Koae fault of 1965. It seems to have closed the connection of Kilauea to the rift. The journey ended where it began – for now.


This all happened 53 years ago. Three years after this eruption, people would first fly around the moon. It was a time of hope when everything was young and anything seemed possible, when small steps for men became big steps for mankind. What happened to the hope? It is not only Kilauea that has changed. All around the world, society seems more divided than ever. The UK is particularly badly hit, and migrants (like me) perhaps feel less than fully welcome these days. Flying around the moon is a thing of the past: we can hardly get a rocket off the ground, whilst still using 1970’s technology. With all our progress, have we gone backwards? But volcanoes still erupt. They are a beacon of reality, and they are still able to surprise us. Volcanoes bring a different perspective.

The walls of the time

Memories are fading; our triumphs soon undone
The footsteps which today we make, tomorrow will be gone
But within us is the will to leave something that will last
a footprint on the river bank, before the current moves us past
as an outcast draws graffiti on a grey and wintry wall
as if to shout ‘I too have lived!’ beyond the empty hall
So I take what courage still remains, and in my feeble rage
I spray the word ‘Hope’ on the walls of this age.

Hearts are closed, unyielding, – with cold and empty eyes
Love surrenders where divisions erupt in fights
So much need and so much worry lies at our door
And when one child laughs, those that cry are ten times more
The heavens turn away, their oversight has failed
The burden on my shoulders in weakness is travailed
But in despair and anguish, my sadness provides the stage
to spray the word ‘Hope’ on the walls of this age.

Madness is king, and around rises the tide
A world is breaking down, and yet I dream of light
We are lost in the darkness, but hope remains the key
Humanity returning in a future I do not see
One day, when on my grave the grass in wind is blown
The words ‘never forgotten’ have long been overgrown
Perhaps between the lasting shouts of bitterness and hate
also the word ‘Hope’ is on the walls of that age

Reinhard Mey: Die Mauern Meine Zeit



From all of Us to all of You

Merry Christmas and Happy Holidays!

178 thoughts on “A Christmas eruption

  1. Ambryms 4 lava lakes are now completely gone.
    No thermal emissions at all recorded from satelites and no gas plumes from the craters.
    Ambrym is silent, but since it must have a pretty large magma supply, Im soure the lakes or one lake at least returns soon enough. For now no lava lakes are present in Ambryms conduits

    • 2018, the year when two of earth lava lakes, including the largest, suddenly terminated. Really, of all the lava lakes active this year only halemaumau and nyiragongo qualified as true lakes, the others are just the exposed tips of magma columns that are only a few tens of meters at most.

      It is lucky kilauea is active enough that it’s LERZ eruptions show precursor activity before the real event begins, in a way the eruption this year started properly on the 18 May, and from that point things really got intense very fast, when the new dike surfaced. Fissure 8 was probably fed out of the summit directly at a deeper level than the other vents, in the same way as 1960 or 1840, before that the lava was hot but poor in olivine so was rift magma likely under pu’u o’o which intruded at shallower levels. Fissure 8 probably didn’t fountain high because the lava was hot enough to melt the narrow vent hole into a wider opening and arrest fountaining, some of the temperatures were around 1200 C which is the hottest flank lava erupted on kilauea in recorded time. This also ties to it being summit magma as the lake had >1200 C lava in it too and was likely hotter in the chamber and even more in the deep system which is possibly where fissure 8 was fed. In a way this hypothesis infers there were actually two simultaneous eruptions, 20, 22, 6, 15, 21 and 7 were fed out of pu’u o’o draining, and while that was still happening possibly as early as May 5 with the big quake was when the deep dike started forming and it intersected the existing dike above it somewhere on the way around the end of May where the gas rich very hot new magma surfaced and all hell broke loose. SO2 reached world record levels when fissure 8 opened, and fountains nearly reached 100 meters as opposed to 50 at earlier vents.
      After fissure 8 opened up also when the summit began collapsing for real, before then it was just collapse of the empty lava lake basin which likely was superficial and had the deep dike not occurred the activity would have likely returned to the summit afterwards, maybe even pu’u o’o again.

      In terms of the deep dike not being detected, most of the distance it had to move would be through rick that is almost incandescent hot and very ductile, meaning the quakes only really show up at the eruption location.
      The May quake could have been inevitable with the formation of fissure 8 also inevitable, it just happened to also coincide with a common pattern of an ongoing large shield which pushed everything over breaking point. Maybe pu’u o’o could have ruptured uprift with large flows there, but then gone way downrift and begin the big drain. Just speculation but interesting and different from some of my other ideas.

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