VOLCANOES
With the renewed interest in volcanoes after the eruption of Mt Agung on the Indonesian island of Bali, Auckland University’s Phil Shane warned that we can expect at least one big eruption in New Zealand in ‘‘our lifetime’’.
‘‘Volcanoes erupt anywhere between one and a thousand years but that eruption could easily be today or the end of the year,’’ says Shane.
Not since 2007, when Mt Ruapehu exploded, has mainland New Zealand experienced an eruption.
Shane said that, unlike earthquakes, which occur without warning, volcanoes usually give off signals weeks, months or even years before an eruption.
According to Newsweek, there were at least between 14 and 27 volcanoes erupting in any week in 2017, and similar numbers are expected in 2018.
Most observed volcanic activity takes place along the Pacific Ring of Fire. Other eruptions occur at volcanoes within continental interiors such as Ol Doinyo Lengai in Tanzania, or on oceanic islands like Hawaii.
Many also take place hidden from view on the sea floor, with some of the most active underwater volcanoes located in the Tonga-Kermadec island arc in the south-west Pacific.
The current eruptions on land range from gentle lava effusions to moderatesized explosions and are tiny compared to the largest in Earth’s history.
Even the 1815 eruption of Mt Tambora, also in Indonesia, arguably the largest eruption in recent recorded history, is dwarfed by super-eruptions in the geological past such as that of Toba volcano on Sumatra some 74,000 years ago, which helped plunge the Earth into another ice age.
In fact, Toba was the largest eruption in the past 25 million years, so there is little chance of a similar catastrophe any time soon.
Nevertheless, it is the frequent, smallto moderate-sized eruptions that pose a constant threat. Around the globe today, about 800 million people live within 100km of active volcanoes.
For example, Auckland’s volcanic field is the most densely populated field of its type in the world.
GNS Science has said researchers had ‘‘no idea’’ when, or where, Auckland’s next eruption would occur.
They were confident there would be another, but when it would come was anyone’s guess.
In April, researchers from the University of Canterbury said a volcanic eruption could bring Auckland to its knees, crippling transport networks and displacing almost one-third of its population.
In March, GNS Science released a report saying the region’s next eruption would likely come from a volcano that doesn’t exist yet.
Aside from Mt Agung in Bali, here are the other volcanoes to keep an eye on in 2018: Kirishima, Japan; Merapi, Indonesia; O¨ raefajo¨kull, Iceland; Popocate´petl, Mexico; Villarrica, Chile; Kilauea, US/ Hawaii.