New Zealand – First Tongariro eruption in over a century

Eruption a total surprise to GNS volcanologists

Mt Tongariro rumbled into life at 11.50pm last night, sending ash and rock a 6/10ths of a mile (1 km) into the air and across roads, prompting a potential threat warning for central North Island regions.

The “small scale” eruption was a total surprise, said GNS volcanologist Michael Rosenberg.

It threw rocks and spewed ash from the Te Mari craters, near Ketetahi hot springs, on the northern side of the mountain, GNS Science said.

Roads were closed, flights disrupted and nearby residents advised to stay indoors as ash and rock spewed from the mountain.

Seismographs this morning were not showing that any more energy was being released, however there was potential for further eruptions. They also showed no activity leading up to or following the overnight hydrothermal, or steam-driven, eruption.

‘WE CAN’T REALLY PREDICT WHAT THIS WILL LEAD TO’

Eruptions had occurred on Tongariro  intermittently from 1855 through to 1897, and it could not be ruled out that this was the start of a prolonged period of activity in the area, Rosenberg said.

“We have to expect the unexpected. We really can’t predict what this will lead to,” Rosenberg said.

“This has taken us by surprise. It’s gone from some little earthquakes that seemed to be tailing off, then all of a sudden this has gone boom.

“We don’t know how long it could go. It could be a one off or it could go weeks, months years or even a decade,” said Auckland University volcanologist Phil Shane. A more violent eruption in the coming days or a drop off in all volcanic activity was also possible, said Shane.

New Zealand Herald reporter Jamie Morton said the ash this morning on SH46 at Lake Rotoaira, just north of Tongariro is a “thick, clay-like mud”, about half a centimetre thick.

“It’s just carpeted everything, all the fields, cars, trees – the whole landscape looks quite murky and grey,” he said.

“Roofs in this area, they’re all absolutely coated in this ash.”

“There is also quite a noticeable smell … quite a murky smell. We’ve had reports in Waiouru that there is a sulphur-like smell in the area. That is not the case here.”

An earthquake lasting about five minutes accompanied the eruption and residents reportedly heard the explosions.

A witness told police the eruption had created “a new hole in the side of the mountain”.

Recent volcanic unrest at White Island was unrelated and coincidental to last night’s eruption at Tongariro.

See video:
http://www.stuff.co.nz/national/7426862/Mt-Tongariro-erupts-for-first-time-in-over-100-years

See also:
http://www.stuff.co.nz/the-press/national/7426862/Mt-Tongariro-erupts-warning-for-central- NI

See also:
http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10825125&fb_source=message

http://www.news.com.au/travel/news/new-zealands-mt-tongariro-erupts/story-e6frfq80-1226444411707

Thanks to Wanda, John Reno, Hayden Nash, Byron Dawes and Carla Burgers in Christchurch N.Z. for these links