New Zealand volcanic activity

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White Island eruption

The first eruption of Mount Tongariro in a century was preceded by a lift in the alert level yesterday of New Zealand’s largest volcano - White Island in the Bay of Plenty

Sun Live,

7 August, 2012

The first eruption of Mount Tongariro in a century was preceded by a lift in the alert level yesterday of New Zealand’s largest volcano - White Island in the Bay of Plenty.

White Island’s alert level was raised to Level 2 at 6.30pm last night – about six hours before the eruption on Mt Tongariro’s Te Mari crater.

A smoking White Island from Looking Glass Gardens in Te Puke. Photo: Jessica Brockett.

GNS Science raised the alert level after the White Island web camera captured a small eruption at about 4.55am on Sunday from the Crater Lake. During the past week there has been an increase in volcanic tremors and volcanic gas levels.

The Volcanic Alert Level is now raised to Level 2 – meaning the onset of eruptive activity, accompanied by changes to monitored indicators and minor eruptive activity.

The Aviation Colour Code is changed to Orange.

This is confirmation that small scale eruptions are now occurring on the island and GNS confirms the risk to visitors has increased.

White Island, about 48km off the Bay of Plenty coast, is an active volcano and there is always risk when visiting the island and vessels travelling nearby should keep alert.

Between Friday, July 27 and Saturday, July 28 the lake level in the Crater Lake at White Island rose by about 3m to 5m.

A volcanic earthquake was also recorded indicating an eruption may have occurred. A flow of gas and steam has been present through the lake and from vents near the lake since then.

A gas flight on August 1 recorded increases of sulphur gases in the steam and volcanic gas plume.

Activity at the island has been increasing since early July with intermittent periods of volcanic tremors, becoming more continuous since July 28. A particularly stronger episode was recorded overnight August 4-5, and ended in a volcanic earthquake at 4.54am.

Examination of the images from the Factory webcam between 4.54am and 4.57am on August 4 revealed an eruption from the Crater Lake.

Meanwhile there have been no further reports of activity from Mt Tongariro which erupted at 11.50pm last night.

The eruption was at the Te Mari crater on the volcano’s north western flank. The crate is the site of the last eruptions in 1869, 1892, 1896 and 1897.

The upper Te Mari Crater was formed during an explosive eruption in 1869. Māori descriptions talk of "bright red flame through the smoke that would burst and fall like snow".

In November 1892 Te Māri again belched forth an immense quantity of steam, mud and boulders; the ejected material rose 2000 - 3000 feet (600- 900 m) before rushing down the mountain side. The last eruption began in November 1896 and activity lasted until October 1897.

There is a media briefing on the Tongariro activity at Taupo at 10am.

The volcanic threat level activity scale:

0 Typical background surface activity; seismicity, deformation and heat flow at low levels. Usual dormant or quiescent state.

1 Departure from typical background surface activity. Signs of volcano unrest.

2 Onset of eruptive activity, accompanied by changes to monitored indicators. Minor eruptive activity.

3 Increased vigour of ongoing activity and monitored indicators. Significant effects on volcano, possible effects beyond. Significant local eruption in progress.

4 Significant change to ongoing activity and monitored indicators. Effects beyond volcano. Hazardous local eruption in progress.

5 Hazardous large volcanic eruption in progress. Large hazardous eruption in progress.

Sulphur smell from Mt Tongariro reaches Wellington

TVNZ,

8 August, 2012

The distinct smell of sulphur from the Mt Tongariro eruption is wafting towards the South Island this morning.

The volcano erupted suddenly on Monday night, spewing ash as far as Napier and Hawke's Bay and causing significant damage to a hut on the popular Tongariro Crossing walking trail.

The smell of sulphur has been reported in the capital this morning, where Wellingtonians have taken to Twitter to describe the "stinky" smell.

"You can smell the volcano outside today - even here in Island Bay, Wellington. It's a bit stinky," tweeted Jayne Fox.

The lingering smell comes as GNS scientists take to the air this morning to get a first-hand idea of how the eruption has affected the crater on Mt Tongariro.

Clear conditions have enabled scientists to fly near the crater after they were unable to see the mountain clearly yesterday because of heavy cloud.

Vulcanologist Brad Scott said better weather today means they can get a clearer picture, but they would be keeping a safe distance from the crater.

They are hoping to take further samples from near the crater to determine if Monday night's eruption was steam or magma driven and the likelihood of a further eruption.

Scientists are monitoring the active volcano around-the-clock as they fear another violent explosion could strike at any time following Monday night's eruption that spewed rocks a kilometre into the air.

They warn the volcanic activity could last for days or weeks, causing concern for residents who have been warned they will be in the firing line if a magma eruption occurs.

However, no further volcanic activity was reported overnight.

Department of Conservation is also hoping to survey the extensive damage the eruption has caused to a hut on the popular Tongariro Crossing walking trail.

Boulders are also believed to have caused significant damage to the walking track.

Last night's wet weather condition are likely to assist with today's clean-up efforts as residents look to clear the thick layer of ash settled around the base of the mountain and in nearby Ohakune.

The dampened ash is easier to clean-up, compared with dry, dust-like ash.

Tongariro 'quiet' before explosion

Auckland University Associate Professor of Geology Dr Phil Shane said GNS scientists saw an increase in seismic activity at Mt Tongariro recently but the volcano was quiet just before the explosion.

"It shows that there isn't always often a fool-proof way of predicting these things," said Shane.

"What we would say is we are in a zone of heightened activity, not to say it will erupt immediately, but we are in a time where we should keep a closer eye than normal."

Shane said it was too simplistic to say if heightened volcanic activity at White Island and Monday night's explosion at Mt Tongariro were related as volcanoes tended to behave independently.

He said Auckland's myriad of volcanoes are very unlikely to be activated by seismic activity in the Central Plateau.

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Mt Tongariro in NZ is not the only place in the world to see volcanic activity

Volcanic activity world-wide 7 Aug 2012: Tongariro, Etna, Stromboli, Popocatépetl, volcanoes in Guatemala, Colombia, Ecuador

Volcano Discovery,

7 August, 2012

News have been dominated by Tongariro volcano's first eruption in 115 years (New Zealand). At the moment, the volcano is quiet, but eruptions could resume any time. 
Etna (Italy): Strombolian activity continues at varying levels. Following a phase of weak activity during 4-6 Aug, an increase of activity was observed at the Bocca Nuova during the night 6-7 Aug. 

 
Also in Italy, the activity at Stromboli (Eolian Islands) has been at relatively high levels over the past days. The number and size of explosions from the summit vents has increased. 
Popocatépetl in Mexico: About 1 explosion occurs per hour, and strong glow is visible at night. A relatively powerful eruption late on 6 Aug sent ash to up to 30,000 ft (10 km) altitude. 
The volcanoes in Guatemala have shown little changes in activity over the past days. 

 
Fuego volcano has intermittent weak strombolian explosions throwing lava up to 100 m above the crater, and the lava flow on the south flank is still active. 

 
Santiaguito / Santa Maria (Guatemala): Weak to moderate explosions occur regularly and produce ash plumes up to 900 meters high. Avalanches of lava blocks descend on the south flank of the dome. 

 
Lots of seismic activity is visible on the seismograms, most of it related to rockfalls. 

 
Some tremor and shallow volcanic quakes and weak degassing are the only signs of activity reported from Pacaya. 
In Colombia, there are currently 1 volcanoes on orange alert (Ruiz)(eruption warning) and 4 on yellow (unrest): 

 
Nevado del Ruiz (Colombia) shows tremor, associated with gas and minor ash emissions at low level. A shallow M1.2 earthquake occurred at 3:11 (local time) near the Arenas crater. INGEOMINAS keeps a close watch of the volcano. 

 
Compared to the previous week, the seismicity at Galeras has increased and shows events related to fluid movements within the volcano. Few weak earthquakes with magnitudes less than 1.1 related to fracturing of rock occurred at shallow depths (less than 4 km) at various locations under the volcano. 

 
Seismicity at Cerro Machin volcano remains at slightly elevated levels with some weak earthquakes SE under the lava dome at depths between 3.5 and 5 km. 

 
At Cumbal volcano, seismicity is still above background levels, but has has decreased. Signals are interpreted as fluid movements under the volcano. 

 
Nevado del Huila The volcano shows normal seismic activity and degassing at low levels with no significant changes to previous weeks. INGEOMINAS keeps the alert level at yellow. 
Ecuador: 

 
Tungurahua volcano: Activity remains generally at relatively low levels. Few small to moderate explosions (about 3-5 per day) and weak steam and ash venting continue at Tungurahua. The last reported ash cloud altitude was at 18,000 ft (4.5 km) from an explosion on 6 Aug.

 
This morning, a more intense phase with volcanic tremor is visible on the seismograms. 

 
Reventador volcano: IG reports a strong steam plume rising 1500 m above the summit, but does no more mention any active lava flow. 

 
Sangay volcano: No recent reports of eruptions from remote Sangay are available, but this might simply incidate that its typical strombolian eruptions are too small.