Virtual Volcano Vacation challenge #85 WINNER! – Tongariro

tongariro-cover

Tongariro volcano from the northeast with Te Māri crater in the foreground- Image found at Geonet

I ought to know better by now than to hide in volcanoes that are surrounded by legends and myths. I like a volcano that is more than just a volcano. I like volcanoes that have stories told about them, and volcanoes that have been given lives of their own and even become perhaps a little anthropomorphized. Those are the ones I fall in love with and want to know everything about, inside and out. This becomes a bit more complicated though when I find myself once again in New Zealand’s volcanic love-triangle investigating the story from Tongariro’s angle.

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Annotated satellite image of Tongariro volcano including names of cones and craters – Image found at ResearchGate

Tongariro belongs to the Taupo Volcanic Zone on New Zealand’s North Island. The zone is actually the southern part of a back-arc basin associated with the Kermadec-Tonga subduction zone. The back-arc basin was created by the subduction of the Pacific Plate beneath the Indo-Australian Plate. The sinking slab (subducting ocean plate) bends sharply at the point where it dives below the continental plate, but the oceanic slab is so heavy that the point at which the slab hinges slowly moves back toward whence the slab came. This pulls at the edge of the continental crust and actually extends it. The thiner-stretched crust becomes a long narrow basin that runs parallel to the oceanic trench. The V-shaped Taupo Volcanic Zone begins at Whakatane just north of Whakaari (White Island) and converges at Ruapehu. The TVZ also includes Lake Taupo, a caldera which erupted 1,170 cubic kilometres of material around 26,500 years ago, earning that eruption the distinction of being Earth’s most recent VEI-8 event.

Shallow Sub Zone

Diagram of how a subduction zone forms a volcanic arc and a back-arc basin through slab-rollback – Image found at wikipedia

Tongariro is part of the Tongariro Volcanic Center made up of four volcanic massifs which also includes Ruapehu, the Kakaramea-Tihia Massif and Pihanga, the last of which I will tell you a little more later. Tongariro is a volcanic complex made of at least 12 cones. The tallest is Ngauruhoe, though that one is often thought of as its own mountain. Ngauruhoe has erupted at least 70 times since 1839, and most recently in 1973. More recently in 2012, Te Māri crater erupted. Red Crater includes many active fumaroles, and other craters have filled with water to become Blue Lake and Emerald Lakes. Tongariro’s altitude causes him to receive snowfall during the winter months between March and October, but most melts away during summer. Unlike Ruapehu, Tongariro has no glaciers, though evidence suggests it was once glaciated.

As with many other volcanoes, the indigenous people living around Tongariro have handed down legends about how the volcano came to be. These legends tend to vary somewhat from tribe to tribe, though with a strong similar thread between them. One widely accepted legend tells of Ngatoroirangi, a Māori priest who journeyed to Aotearoa (the land now known as North Island, though the name is sometimes applied to the whole of New Zealand) in Arawa, one of a fleet of seafaring canoes that the Māori people used in their migration from Hawaiki (the legendary place of their peoples’ origin). When Ngatoroirangi saw the highest peak of the volcano, he set out to climb it. Before leaving, he asked his followers to fast until his return. However just before he reached the top they disobeyed him, and for that, a cold south wind blew upon him, bringing Ngatoroirangi close to death. He prayed to his gods in Hawaiki to send him fire to keep warm, and his gods did just that, sending the fire underground by way of Whakaari, Okakaru, Tarawera, Taupo and the other volcanoes along the way.

tongariro-erupt

A vulcanian explosion from Ngauruhoe volcano in New Zealand on February 19, 1975, ejects a dark, ash-laden cloud. Large, meter-scale ejected blocks trailing streamers of ash can be seen in the eruption column. Blocks up to 20 m across were projected hundreds of meters above the vent. – Photo by Ian Nairn, 1975 (New Zealand Geological Survey). – Image and caption found at GVP

Yet another Māori legend tells of Tongariro’s conflict with the volcano Taranaki, who now lies far west of the Tongariro Volcanic Center. When I visited Taranaki, the legend I found said that Taranaki, Ruapehu, Tongariro and Ngauruhoe (the last two actually being geologically one volcano) all were trying to win the love of Pihanga, a green volcanic mountain now located East of Tongariro. Tongariro soundly defeated Taranaki and the bested and heartbroken Taranaki exiled himself to the west, carving out a swath of land in his retreat that would later become the Wanganui river. Since then I found a seemingly equally accepted version of the story in which Ruapehu was Taranaki’s wife. In that legend, Ruapehu was unfaithful and went to Tongariro while Taranaki was out hunting, and he came back and caught her in her infidelity. In that version, she still loves him even though he is far away, and occasionally sighs in her longing for him. Meanwhile, Tongariro rumbles to remind Taranaki to keep his distance.

tongariro-legend

The legend of Tongariro and Taranaki as illustrated in the book The Battle Of The Mountains by Peter Gossage – Image found at TeAra.govt.nz

Tongariro and the surrounding volcanic center are now included in Tongariro National Park, New Zealand’s first national park and also a world heritage site.

Thank you Jesper for finding me, and thank all of you for your patience with my slow-coming post. This coming week I’m off to hide again, but am hoping to see you…and you…AND you..and YOU too (yeah, you know who you are) this next week beginning Monday midnight (New York time) and we’ll have a new adventure on a new volcano.

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