A trip to New Zealand
(By Claude Grandpey, president of LAVE, the "European Association of Volcanology")
Surprisingly, I don’t think immediately about volcanoes when I hear about New Zealand. The first idea that comes to my mind is the All Blacks, the famous rugby team whose haka is destined to impress their opponents even before the start of the game.
New Zealand also reminds me of my years at the University when I had to study the birth of the Commonwealth of Nations. It’s the reason why I was eager to visit the House in Waitangi where the Treaty was signed on February 6th 1840, giving a new structure to this country.
As the grandson of farmers, I also think about New Zealand agriculture, mainly the sheep whose flocks include thousands of animals with which French farmers can’t compete and feel desperate when they see New Zealand lamb meat in the freezers of supermarkets!
Why are volcanoes so low down the list? Probably because I don’t find them active enough! It is true White Island or Mount Ruapehu can go through very violent eruptive crises, but they are quiet the rest of the time and the geothermal springs of Rotorua can’t appease my hunger for volcanoes! They can’t bear the comparison with the lava flows of Hawaii or even Mount Etna…
Why are there volcanoes in New Zealand? It is because the country is located on the Ring of Fire, at the boundary between the Indo-Australian and the Pacific plates. The collision of these two plates causes a subduction of the Pacific Plate under the Australian Plate. The Taupo Volcanic Zone stretches over 250 km from White Island to Ruapehu. In the South Island, the reverse happens and the collision between the two plates has given birth to the Southern Alps that lift up by several millimetres each year.
I spent four weeks driving all over New Zealand in February 2009. The trip started in Auckland. After a short visit in the northern part of the North Island and a visit of the Treaty House of Waitangi, I drove along the coast of the Coromandel Peninsula and then to Whakatane where a helicopter flew me to White Island, the first major volcanic stop of my journey. The weather was beautiful, so that the brown and ochred colours of the rocks contrasted with the deep blue of the sea while the acid lake displayed a nice green colour in its mineral setting.
After flying several times around the island, the pilot finally landed in the horseshoe depression surrounded by the walls of the volcano. This was really a great moment for me, a moment I had been dreaming of for a long time!
White Island lies some 50 km from the coast and covers an area of about 5 square kilometres. It is located at the north-eastern end of the Taupo Volcanic Zone that includes all the main active volcanoes of New Zealand. Some 36 eruptions have occurred since the first historical observation in 1826. In July 2000, the most violent eruption of the last 20 years lasted 5 hours; it gave birth to a new crater and covered the eastern part of the island with blocks and ash. Today, the volcano is quiet. There are just a few fumaroles and mud or hot water pools whose temperature was about 80°C when I measured it during my visit. The colours of the rocks are really beautiful, as well as that of the acid lake whose Ph can be negative!
As soon as one arrives in Rotorua, the odour of hydrogen sulphide and the vapour clouds that can be seen in the parks of the town leave no doubt about the geothermal activity of the region. Several sites such as Hell’s Gate, Waimangu, Wai-O-Tapu or the Hidden Valley d’ Orakei Korako are really worth a visit, with the fantastic colours offered by Nature’s palette. As far as geysers are concerned, they are far less numerous and less nervous than at Yellowstone in the US. Would you belive it! Lady Knox needs to be wakened with cakes of soap…!
After two days in Rotorua, I drove along the Taupo Volcanic Zone and made a stop in the Tongariro National Park dominated by Mounts Tongariro, Ngauruhoe and Ruapehu. A good way to see them is to buy a scenic flight that allows to visit the region without making any effort! Mount Ruapehu is the most dangerous of the lot as its eruptions often occur without warning, just like most other volcanoes located in subduction areas. For instance, on December 24th 1953, an eruption triggered a lahar that swept away a railway bridge as a train was passing on it, killing 151 people. The materials emitted by the last eruptions has trapped a lake in the crater, with the risk to see it overflow and cause a new destructive lahar.
Mount Ngauruhoe’s eruptions can be a threat too. The latest one occurred in July 1977 with several explosions. Today, the volcano is very popular in New Zealand as it was used as a stand-in for the fictional in 's .
Another way to discover the region is to do the Tongariro Crossing, an 18-km trek that spans the length of Mt Tongariro, with great views on the volcanoes, without forgetting the Emerald Lakes along the footpath.
Even though there is no active volcanic activity on the South Island, the collision between the tectonic plates has given birth to the Southern Alps, a mountain range dominated by Mount Cook (3754 m) and Mount Tasman (3497 m). The glaciers that surround the summits are a major tourist attraction. Once again, a good way to discover this region is to fly over it.
Even though volcanism is not as active as in other parts of the world, this deficiency is largely compensated for by the beauty and the contrasts of the landscapes. If you happen to visit New Zealand, don’t hesitate to leave the main roads and drive along gravel roads in order to get into the heart of the country. Just take the boat, the plane or the helicopter; you won’t be disappointed. Have a nice trip!
