Update 7 August 2012. For a full update to this story click here Mount Tongariro Erupts ash cloud headed east.
Scientists are saying that the activity could continue for months, even years after the volcano had lain dormant for almost 100 years.
Civil Defence has said that volcanic activity may threaten Waikato, Hawke’s Bay, Gisborne, Manawatu-Whanganui, Bay of Plenty and Taranaki. People living in those areas have been advised to stay indoors with all the windows and doors closed and listen to the radio for updated emergency information and instructions.
Despite the volcano showing signs of increasing activity over the last few weeks and the raising of alert levels, NZ scientists are claiming the eruption came as a “total surprise.”
Mount Tongariro last erupted in 1897 marking the end of a decade of activity.
Earlier this month authorities issued an alert for the volcano following a recent increase in the number of volcanic earthquakes. Today we hear that activity continues, along with an increase in volcanic gases from the mountain.
The Geonet website posted another alert today.
“Analysis of the gas samples collected in the last fortnight shows that volcanic gas levels are above the normal levels measured at Tongariro. There is always a mix of volcanic and hydrothermal gases and fluids rising to the surface at Tongariro, but the recent samples contain a marked increase in the volcanic gas component. These results confirm the volcanic unrest indicated by the seismic data.
We are working to complete the analysis of the water samples and plan more field work within the next two weeks or sooner if activity changes significantly. GNS Science volcanologists are monitoring the unrest and further information will be released as necessary.
Mount Tongariro is a volcanic complex that lies to the north of Mount Ngauruhoe. It consists of numerous craters, cones and lava flows. Te Māri craters lie about two kilometres east of Ketetahi hot springs on the north side of Mount Tongariro. The Te Māri craters are the last craters to be active on Tongariro. Ash eruptions from Tongariro are recorded from 1855 to 1897, as well as unconfirmed activity in 1926-27.” more here
Mount Tongariro, along with Mount Ruapehu and Mount Ngauruhoe form the Tongariro National Park in the North Island of New Zealand. According to the Geonet webste there have been five reported eruptions from the Te Māri craters between 1855 and 1897. They are the last craters to be active on Tongariro.
Mount Ngauruhoe and Mount Ruapehuwere used to depictMount Doom in Peter Jackson’s Lord of the Rings trilogy. But in long shots either CGI or a model was used as the mountains are sacred to local Maori
Major Eruptions in 1990s
In April last year a similar alert was issued for Mt Ruapehu when its crater lake began to heat up. Mt Ruapehu typically has small eruptions every dozen or so years and larger eruptions about twice a century. Many people will experience it at least once in their lifetimes.
In the mid 1990s no-fly zones were declared in the North Island and 11 airports closed, causing disruption to thousands of passengers. In those days a million fewer people lived in New Zealand and Auckland’s population was around 870,000.
The Ruapehu eruptions discharged a total of 60 million cubic metres of acidic ash, covering land up to 300km from the volcano.
At the peak of Ruapehu’s eruptions, ash plumes reached to 10 kilometres high and volcanic ash spread over large parts of the North Island.
Aviation authorities declared no-fly zones in the North Island and up to 11 airports were closed. The plans of thousands of airline passengers were disrupted. Ash also caused millions of dollars of damage to hydro-electric turbines and electricity transmission facilities in the central North Island. More here.
If you live in New Zealand this could be a good time to be checking your insurance policy and re-stocking your emergency supply cupboard. For details on how best to prepare for a volcanic eruption in New Zealand go to Getthru.govt.nz be sure to pack water and dust masks.