The “Ring of fire” is a zone around the Pacific Ocean that contains about two-thirds of the world’s active volcanoes.

Countries on the ring such as New Zealand, Vanuatu and Papua New Guinea have active volcanoes, but not Fiji. However, volcanic heat is not far below the surface in some places on Viti Levu and Vanua Levu.

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Fiji is lucky -- we’re on the Pacific “Ring of fire”

The earth’s core is 4200 degrees Celsius at the centre. Closer to the surface it is much cooler. Only in a few countries of the world is this heat close enough to be reached by drilling holes in the ground. Fiji is very lucky to be one of those countries -- it sits on the Pacific Ocean’s “Ring of fire”. In most countries the same temperatures are only reached many kilometres below ground.

If water from rainfall or the ocean seeps into deep cracks in the earth, geothermal heat can turn the water into steam. Sometimes this comes to the surface as a huge “geyser” of steam and hot water.

Geothermal Electric Limited geologists have conducted technical assessments of all hot springs in Fiji.

More often, hot water flows to the surface and bubbles of steam appear if the water is above boiling point – just like a vigorously boiling kettle. This is the case in Fiji. These hot springs have been used for cooking since ancient times.

Although hot springs can give a hint about where to look, finding heated water at the right temperature and quantity to power a geothermal electricity plant can be very difficult. Drilling to explore for water usually involves holes between 300 to 3,000 metres deep, or even further -- compared with 30 metres for a typical village well. Often drill-holes have to be abandoned because they remain dry, even though it may be discovered later that water is not far away. That's why, although decisions on where to drill make use of geological science as much as possible, there is a high element of luck when drilling for geothermal hot water. At up to $5 million per drill hole, it is expensive for the exploration company if luck runs out.

The conclusion: Fiji is very lucky to be on the "Ring of fire". Hopefully, good luck will combine with science to make the geothermal drilling program succeed.

Click for a diagram of how heat in a geothermal reservoir under the earth’s surface is accessed by drilling.

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