Geothermal activity

New Zealand straddles an active fault line where two giant pieces of the earth's suface are in a constant state of collision. In the South Island they meet and push upwards, creating the towering Southern Alps; around the central North Island, one piece is creeping slowly under the other, generating enormous amounts of subterranean heat and volcanic activity.

All around Rotorua, sneaky threads of steam drift upward from parks, river banks and drains. The unmistakeable scent of sulphur wafts through the air. Minutes from the city centre, geysers of boiling water roar from the ground and pools of bubbling mud gurgle and belch.

Geothermal and volcanic activity have sculpted the landscape in every direction. The many beautiful lakes are water-filled craters from violently explosive eruptions. Giant sleeping volcanoes rise all around and gently oozing lava has created conical hills and islands. Silica terraces and the edges of ponds have been beautifully coloured by minerals extracted from deep inside the earth by the rising superheated water and steam.

Since the arrival of the first Maori settlers, people have harnessed this vast renewable energy source for cooking, heating and, more recently, electric power production. You'll discover that a relaxing soak in naturally heated water is the perfect end to a day of geothermal exploration.

Mount Tarawera

For centuries the Tuhorangi tribe (a sub tribe of Te Arawa) held Mount Tarawera in the highest regard. Their leaders were buried on its summit, and the bones of countless ancestors were entombed around its base.

Imagine their grief when, in the early hours of 10 June 1866, the mountain began to erupt, thrusting columns of molten rock thousands of metres into the air. A thick dark cloud formed high above the eruption, its underside lit coppery red by the activity below. Lightening and thunder broke out and molten balls of rock began to rain down onto the lake and surrounding landscape.

Worse was about to come. Beneath the earth's surface, hot magma met the underground waterways of nearby Lake Rotomahana. This rapidly created a vast amount of superheated steam that simply blew the bottom out of the lake, sending scalding mud high, far and wide.

For the surviving local Maori, the eruption was devastating. Their ancestors' remains were destroyed, many of their people were killed and their lands and livelihood were metres deep in mud and ash. In addition, the amazing Pink and White Terraces - recognised as the eighth wonder of the world - were completely destroyed.

Today the giant mountain lies sleeping once more. Its crater, a gaping six kilometre ravine, is clear testament to the ferocity of the 1866 eruption. Access onto the mountain is restricted to guided tours. Its majesty can also be viewed from a scenic flight.

Kuirau Park

The northern end of Rotorua has a public park that is definitely alive and well. Walking tracks lead to numerous areas of vigorous geothermal activity. Provided you stay on the cool side of the safety fences, visitors are generally quite safe. New eruptions do occur from time to time, so it pays to err on the side of caution. In 2001 mud and rocks the size of footballs were suddenly hurled 10 metres into the air as a new steam vent spontaneously announced its arrival. Two years later, similar eruptions provided a real bonus for delighted visitors.

In early Maori times the small lake in the park was much cooler and was known as Taokahu. Legend tells us that a beautiful young woman named Kuiarau was bathing in the waters when a taniwha (legendary creature) dragged her to his lair below the lake. The gods above were angered and made the lake boil so the Taniwha would be destroyed forever. From that time on, the bubbling lake and the steaming land around it have been known by the name of the lost woman, although the spelling has changed a little.

Lake Rotorua

This beautifully peaceful lake has a violent history. One of several large volcanoes in the Rotorua region, its underlying magma chamber collapsed after a massive eruption around 200,000 years ago. The collapse created a circular caldera about 16 kilometres wide, which filled with water to form the North Island's second largest lake.

Geothermal activity continues below and around Lake Rotorua. Clouds of steam drift around the shore and the water has a high sulphur content, resulting in a magical green-blue colouration.

Mokoia Island, in the centre of the lake, is a rhyolite dome formed by slowly oozing lava. This island was the setting for one of New Zealand's greatest love stories - the tale of Hinemoa and Tutanekai.

The beautiful maiden Hinemoa was the daughter of an influential chief. She lived on the eastern shores of Lake Rotorua and was regarded puhi (sacred), which meant that her tribe would choose her husband. Many suitors came seeking her hand, but none met the approval of her tribe.

On Mokoia Island lived a family of several brothers including Tutanekai, the youngest. At a tribal gathering, where young warriors practiced their fighting skills, Tutanekai saw Hinemoa and fell in love. Tutanekai's weaponry prowess and good looks caught Hinemoa's eye, and she too was smitten. However, neither could see a future together - Tutanekai was considered too lowly born to wed Hinemoa.

Poor, sad Tutanekai would sit on the shores of the island playing sorrowful music on his flute. The music would waft across the lake to where Hinemoa waited forlornly. Aware of what was going on, Hinemoa's people made a practice of pulling the tribe's heavy canoes all the way up the beach. But they didn't count on Hinemoa's ingenuity.

One night Hinemoa fashioned a life-belt from empty gourds and swam towards the sound of Tutanekai's flute. She finally made it to Mokoia Island and headed straight for the island's hot pool, Waikimihia, to recover from her cold swim. While she was warming herself, Tutanekai's slave came down to the pool to fetch water. In a gruff voice, Hinemoa called ‘Mo wai te wai?’ (For whom is the water?). The slave answered ‘Mo Tutanekai’ (For Tutanekai). Hinemoa grabbed the calabash he was carrying and smashed it on the side of the pool. When the slave returned to Tutanekai and told him what had happened, Tutanekai went to investigate. The two lovers were at last united, and Hinemoa's tribe accepted Tutanekai as her husband. A very happy ending.

Today the history and natural beauty of Mokoia Island can be explored on a guided tour. Visitors can also enjoy a soak in Waikimihia (now known as Hinemoa's Pool), on the south eastern side of the island.