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20th February 2012

A Marvellous Day in Waimangu Geothermal System, the Youngest in the World

Vessel of Remembrance
Looking Down Waimangu Valley Towards Cloud Covered Mount Tarawera
    After a spot of rain through the night, I headed under leaden skies down to the Waimangu Volcanic Valley, and fortunately to sunnier climes.
    Waimangu is the only hydrothermal system in the world, the commencement of whose surface activity can be pinned down to an exact day, namely 10th June 1886. On that day a violent volcanic eruption punctured the country in this locality with a series of craters, and allowed geothermal fluid already present underground direct passage to the Earth's surface. Since the time of their formation, development of the new geothermal features have been recorded.
    The Waimangu Geothermal System is the newest geothermal system in the world, and the only one wholly created as a direct result of a volcanic eruption. The evolution of the Waimangu Ecosystem has been carefully recorded, giving a unique record of the establishment of a new ecosystem.
Emerald Pool in Southern Crater
    At the beginning of the trail down the valley, a Vessel of Remembrance stood, to remind us of Ruaumoko trembling in Papatuanuku's belly which lead to the eruption of Mount Tarawera; He tohu whakamaumahara ki a Ruaumoku.
    Ruaumoku represents earthquakes and all volcanic phenomena.
    It is by these means that man feels the trembling of the unresting child within Papatuanuku (Earth Mother).
    Ruaumoku is the unborn child of Papatuanuku (Earth Mother) and Rangi (Sky Father). Papatuanuku was pregnant when she was turned face down to Rarohenga (the Underworld or Spirit World). Hence Ruaumoko never emerged into the upper world or saw the light of day.
    Ruaumoko, together with Whiro his brother, makes wars against the offspring of Tane (mankind) to avenge the separation of their parents (Earth and Sky). Whiro suggested that they should return to ao turoa, the upper world, to fight. But Ruaumoko said, "You belong to the upper world. Go you thither and fight, But I belong to the under world and I will conduct my own warfare." Whiro inquired, "But what weapons will serve you?" Replied Ruaumoko, "I will procure one from Puna-te-waro, where-in is conserved ahi-komau" (subterranean Fire, also known as ahi-tipua, supernatural fire).
Frying Pan Lake Inside Echo Crater , the World's Largest Hot Water Springs
Mineral and Algae Deposits at Hot Water Creek
    Earthquakes are caused by Ruaumoko turning over in his subterranean home. If summer is approaching he is said to be turning warmth uppermost; if winter approaches, cold uppermost.
    Ngati Awa people believe that Ruaumoko is also the origin of thunder, which he uses to separate summer and winter.
    Ruaumoko took Hine-nui-te-po as his wife in the underworld. This is curious because, while Ruaumoko is the destroyer of mankind, Hine is the protector of the spirits of the dead.
Boiling Fountains Everywhere
    As I started to head down the trail, the skyline was dominated by Tarawera mountain, a restlessly sleeping volcano which has erupted five times in the last 18,000 years. I stopped off at a panorama viewpoint, which overlooked Waimangu. Before the 1886 eruption, this area was rolling scrub-covered hills with no surface hydrothermal activity. Then, during the night of 10th June 1886, a line of craters from the northern end of Tarawera all the way to the Waimangu Valley was formed by violent eruption. This event completely destroyed all plant, animal, and bird life in the whole of the area visible from this point. All the lush vegetation I could now see has resulted from plant re-colonisation since that date.
Inferno Crater Lake
    Carrying on downhill I came to the Southern Crater, formed by the 1886 eruption, and about 50m deep. A cold water pool sat in the bottom, supporting huge mats of algae and sphagnum moss, earning it the name, Emerald Pool.
    Lower down still I came across Echo Crater and Frying Pan Lake. Echo Crater is an elongated crater originally excavated by the 1886 Tarawera eruption sequence, and it has been reshaped by subsequent hydrothermal explosions.
    The hot water and steam comprising the geothermal fluids discharges at Waimangu and all the other high temperature systems in the Taupo Volcanic Zone is dominantly rainwater that has percolated down through the relatively porous rock found in this region. At depths of between 5km and 10km, it has been heated by conduction from magma residing even deeper. Such heating makes water more buoyant and it rises in a convective plume towards the surface, on the way dissolving minerals from the rock through which it passes. A small proportion of water is probably volcanic in origin, and so there also will be some minerals and gasses such as carbon dioxide and hydrogen sulphide.
Looking Down Rift Valley to Lake Rotomahana and Mount Tarawera
    Immediately after the 1886 eruption, a heated ground-water lakelet formed within Echo Crater, but this water body quickly cooled and for about 18 months there was little sign of thermal activity. Later, geothermal fluid started to find its way up to the lakelet from a previously hidden reservoir that underlies much of the region between Lake Tarawera and south to Rainbow Mountain and beyond, and surface activities of the Waimangu geothermal system came into existence.
    By the late 1890s, erosion of the soft volcanic material covering the surrounding land gradually filled the floor of Echo Crater with sediment until the lakelet had been almost completely displaced. Visitors to the Waimangu Geyser could walk across the resulting thermally active sandy floor, which became known as Frying Pan Flat, and could this way approach the crater of the Waimangu Geyser during its quiescent stages.
    The hydrothermal eruption of 1st April 1917 re-excavated the south-western end of Echo Crater, almost completely blowing away Frying Pan Flat. The new basin formed by this outbreak quickly filled with rain water and with geothermal fluids discharging from vents in its floor, and formed Frying Pan Lake as we see it today. Covering 38,000 sq. metres, it is the world's largest hot spring. With an average depth of 6m, the lake contains 200,000 cu. metres of bubbling, steaming liquid with an average temperature of 55�C.
Marble Terrace
    The ground levelled out now, and I came to a large basin bordered by hills on three sides, once the basin of the Waimangu Geyser. Active between 1900 and 1904, Waimangu was the world's largest known geyser. Erupting sometimes up to 400m high, and hurling black sand, mud and rocks into the air, Waimangu Geyser followed a 36 hour cycle of activity, with eruptions lasting five to six hours. It was a major attraction and the main reason for tourism becoming established here after the 1886 eruption. In October 1904, eruptions started to become erratic, and the last display was on 1st November 1904.
    The outflow of the Frying Pan Lake flowed through a notch at Hot Water Creek and Springs, at a temperature of 50�C with a throughput of 110 litres per second. Along its margin the stream formed deposits which contain traces of elements such as antimony, molybdenum, arsenic and tungsten. These minerals, along with blue-green algae, form spectacular orange, brown, green and yellow colours along the edge of the hot springs.
Warbrick Terrace
    I took a climb up to Inferno Crater Lake. The name of this crater is a modification of the picturesque informal name "Gateway to the Inferno" used to describe this portal to the underworld by the surveyors who first mapped the area after the 1886 eruption.
    The steaming, pale-blue jewel of Waimangu lies in an 1886 crater blown in the side of Mount Haszard. The lake level follows a complicated rhythmic cycle, with lake levels changing by as much as 12m over a 5-7 week cycle. Today it was half full, or half empty, depending on your outlook in life, but despite that, the colour and setting were stunning.
    At this point I opted to follow the Mount Haszard hiking trail, which skirted around the side of the blue lake, and climbed up over the mountain, taking in another panoramic view of Echo Crater, and also a good view down the Rift Valley along the line of craters formed.
    More craters along the rift came into view along the trail, namely the 56m deep Fairy Crater and the Black Crater.
Pretty Berries
    The hiking trail dropped back down to the valley floor, and I picked up the original trail and followed it to the Marble Terrace. The terrace was composed of a similar material to the Pink and White Terraces that were situated on Lake Rotomahana, but destroyed by the 1886 eruption. The terrace was formed by silica depositing out of solution and building in successive layers over time. The colours ranged from a yellow-ochre through to brilliant white.
    I carried on to another set of terraces at the Warbrick Terrace, named after Alfred Warbrick, reputed to have been born on the shores of old Lake Rotomahana, and spent 45 years as a guide in the Rotorua region.
    As I've said before, I'm a sucker for geology, and I found the Waimangu Geothermal System marvellous: its history, and how the subsequent geology and ecosystem has been recorded. It is well worth the visit.
    I returned back to camp in what was now brilliant sunshine, and decided to just chill out rather than dash off to the next location. I spent a while in one of the thermal pools, which initially made my skin tingle. A family joined me: a chap, his wife, his sister-in-law and the latter's grandson. The chap was outnumbered, so we struck up a conversation quite quickly. He originated from near Cardiff, but he moved to Australia with his parents when he was quite young. He still had a fondness for his old country, and liked to visit when he could, but he would never move back. "Who did you support during the Rugby World Cup?" I asked, tongue in cheek. "Lots of people asked me that question. I never gave an answer until after the game," he laughed, as he slowly slipped into a Welsh accent. "My father used to play for Wales as a schoolboy. He was small, played on the wing, but he was fast, really fast. That was a long time ago, early 1930s I think. He won't watch rugby now, he says it is not the same game that he used to play," he added.
    He recounted an amusing story about the village dances where he lived just outside Cardiff, the night when Tony Dawson (I think that was the name) was singing in a rock-and-roll band as a fifteen year old. Sadly I dare not relay the story here in case I fall foul of libel actions. Suffice it to say, that young singer went on to become Tom Jones. How he laughed.
    The chap had been given his instructions by his wife, and had to leave; they were taking the grandson to a Maori entertainment evening and a hangi - it was the lads first time out of Australia.

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Uploaded from Top10 Campsite, Rotorua on 21st February at 09:20

Last updated 20.2.2012