What’s lava got to do with it?

What’s lava got to do with it? Quite a bit if you’re talking about volcanoes.

As a kid I had recurring nightmares about both volcanoes and earthquakes. I blame the abundance of seventies-era disaster movies that seemed to often make it onto the television during that period. I took games of “the floor is made of lava” Very Seriously.

My antipathy towards earthquakes has become less nightmare-based and more practical since 2010, but my morbid fascination with volcanoes is still one that I enjoy (not sure that’s the right word, exactly) though thankfully from something of a distance.

Certainly, Hawaii’s Big Island is plenty close enough for me. Mt Kīlauea started erupting in early May and is still doing a very convincing “Mount Doom”, destroying around 600 homes in the process (so far), and with no signs of stopping.

But New Zealand sits on the same Pacific Ring of Fire as the Hawaiian islands, Indonesia’s Krakatoa, Japan’s Fujiyama and Bali’s Mt Agung which is currently ejecting 2km high columns of ash. Our own history and landscape is peppered with reminders of eruptions, like the caldera that became our own Lyttelton Harbour, for instance.

Volcanic eruptions can and do happen in New Zealand, sometimes with devastating effect (looking at you, Mount Tarawera), so it’s probably just as well that we know something about what they are and how they behave (and preferably from a better source than an old Paul Newman movie).

If you’re keen on finding out more about lava, fissure vents, and pyroclastic flow, you could do worse than consult some of the resources below:

Gale Interactives screenshot
Gale Interactive: Science lets you remove half a mountain to see what’s underneath. In this case, it’s a magma chamber.

And if that’s not enough to quench your thirst for everything volcano, there are also lots of books on volcanoes, for kids and adults alike.

Cover of Volcanoes and thermal wonders

Fireworks on a global scale

cover for the book EruptionWe all know about volcanoes right? After all here in Christchurch we’re virtually sitting on one which provides both of our local harbours.

But did you know about supervolcanoes? They’ve been in the news lately because at the best known one in Yellowstone National Park scientists have just finished measuring its magma chamber. It’s even bigger than they thought at fifty five miles across. That’s a lot of lava.

The other one you will have heard of is Lake Taupo, which is what remains of a supervolcano that exploded 65,000 years ago thereby helping to form the central plateau of the North Island.

The thing about supervolcanoes, of which there are a number on earth (estimates vary) and others known on Mars and Jupiter’s moon Io, is that they are also super spectacular. When magma from a chamber 55 miles across explodes it is world changing. When Taupo went up, evidence was noted by the Romans on the other side of the world in the form of unusual sunsets. It is thought that one in Siberia was responsible for what is known as “the great dying” the greatest extinction event on earth of all time.

Fortunately they only blow very occasionally, even in terms of geological timescales so you don’t need to lose any sleep over them. You don’t need to worry about our own Banks Peninisula volcano either by the way. It was pretty big but its magma chamber is empty.

Tongariro erupts

June 1870:

The Evening Post of the 9th says “On the 2nd instant Dr. Hector received a telegram from Mr. Park, the telegraphist at Runanga, informing him that Tongariro had been ‘in a state of active eruption for some days, and that the red glare was visible from Runanga Mountain, and also from Tapuaeharuru, at the north end of Taupo Lake. Yesterday evening he received a further telegram, stating that the flame is increasing, and that a sound like thunder is distinctly heard at Tapuaeharuru, and occasionally even at Runanga, which is situated 50 miles in a direct line from Tongariro.

The telegram states that there are two points of eruption one at the top, and the other on one side of the mountain, by which is meant, no doubt, not Tongariro proper, but the more recent and lofty cone Ngauruhoe. Dr. Hector informs us that in January last there appears to have been a discharge of hot ashes, which melted the snow where they fell off the slopes of Ruapehu, and that in October a red glow was observed to be reflected from the clouds overhanging the cone. In 1867 the natives told him that in the month of May in that year flames were seen to issue from Ngauruhoe, attended by an eruption of ashes which reached as far north as Henemaia, or 35 miles in a straight line, covering the ground with a white dust, like snow.

The last marked eruption, attended by loud noises, which the natives reported, was in 1865, when the Taupo district, and even the water of the lake, were covered with several inches of black dust. The showers of ashes that on this occasion fell into the Rotoaira, a small lake between the volcano and Taupo, were so dense as to poison the fish. Judging from the above information, the present eruption appears to too more violent than any of the above-mentioned, and may, perhaps, be attended with a discharge of lava, which has never previously bean observed in connection with this volcano.”
TONGARIRO IN ERUPTION. Daily Southern Cross, Volume XXVI, Issue 4000, 17 June 1870, Page 4

More information on Tongariro