White Island latest

VOLCANIC ALERT BULLETIN: WI – 2013/13
White Island Volcano
Volcanic Alert Level 1
Aviation Colour Code: Green
1 pm Monday, 29 April 2013

Aviation colour code changed from Yellow to Green
White Island low level volcanic activity persists
Volcano Alert Level remains at 1

White Island volcano has remained at a persistent low level of activity, including volcanic tremor and degassing, for the past month. No small mud or ash eruptions have been observed since earliest April. The lower level of activity has prompted GeoNet to reduce the aviation colour code to Green (indicating no active eruption activity) from Yellow (indicating heightened unrest and eruptive activity). Volcano Alert Level remains at 1.

Seismic tremor has continued within a range of low to moderate amplitude levels, while gas measurements continue to show a consistent magma degassing signature. Brad Scott who visited the volcano last week confirms “the rainfall over the past few weeks has caused a lake level increase and the two lakes have joined creating one larger lake. Temperature of the lake is variable, with a maximum ~62^oC being measured. In contrast the nearby lava dome which was extruded in November has temperatures of ~200^oC”.

As part of GeoNet's programme to improve monitoring at White Island the web camera on the crater rim has been upgraded. This provides clearer pictures and better low light (night) views. Camera images can be seen here http://www.geonet.org.nz/volcano/info/whiteisland

Background
The GeoNet project is funded by EQC and provides monitoring for all of New Zealand’s volcanoes.

The camera technology uses two cameras: One is a standard daylight camera and the other a special low light camera. The low light camera amplifies any ambient infrared source from various natural sources, allowing us to see better night images. It is not imaging heat but it amplifies low levels of ambient light that contain energy, so they appear as glows in the images. The camera isn't a thermal imaging camera. GeoNet has the same technology installed at other volcanoes. Camera images can be seen here http://www.geonet.org.nz/volcano/info/whiteisland

Aviation Colour Codes are based on four colours and are intended for quick reference only in the international civil aviation community.

The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano. Level 1 indicates signs of volcanic unrest.

Contact: Brad Scott
Duty Volcanologist

VOLCANIC ALERT BULLETIN: WI – 2013/12
White Island Volcano
Volcanic Alert Level 1
Aviation Colour Code: Yellow

3 pm Tuesday, 26 March 2013

White Island Resumes Pattern of Minor Activity
Volcano Alert Level and Aviation Colour Code Unchanged

GNS Science says that a pattern of repeating minor activity has become established at White Island over the last month. The Volcano Alert Level and Aviation Colour Code remain unchanged at 1 and Yellow, respectively.

Periods of passive steaming and degassing have been accompanied by very low levels of volcanic tremor. This activity has alternated with minor mud and steam explosions from the active crater when there has been strong volcanic tremor. Tremor episodes have lasted from less than 1 day to over a week.

Recent airborne sulphur dioxide gas measurements on 20 March were at similar levels to over the last month (550 t/d) although carbon dioxide levels were higher (2400 t/d).

The potential for larger, more explosive eruptions that might impact on visitors to the island is always present. Any larger eruptions may occur with no warning to any visitors to the island.

The ultimate outcome of the current activity at White Island remains unclear and GNS Science continues to closely monitor White Island through the GeoNet project.

Background
Unrest at White Island began in July 2012, leading to explosive eruptions and ash emissions in August. A small lava extrusion occurred in November, followed by phreatic, steam driven activity in December which continued through January and February 2013. Very minor ash emissions have been interspersed throughout this eruption sequence as conditions within the craters have changed.

The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano. Level 1 indicates signs of volcanic unrest.

Aviation Colour Codes are based on four colours and are intended for quick reference only in the international civil aviation community.

The GeoNet project is funded by EQC and provides monitoring for all of New Zealand’s volcanoes.
http://www.geonet.org.nz/volcano/info/whiteisland
http://www.gns.cri.nz/Home/Learning/Science-Topics/Volcanoes/New-Zealand-Volcanoes/White-Island

VOLCANIC ALERT BULLETIN: WI – 2013/11
White Island Volcano
Volcanic Alert Level 1
Aviation Colour Code: Yellow

4pm Monday, 4 March 2013
White Island Volcano Alert Level reduced to 1.
Aviation Colour Code to Yellow.

Ash emission at White Island has ceased for the moment and the Volcano Alert Level is reduced to 1 with the Aviation Colour Code changing to Yellow.

Observations in the last week have shown that a small ash cone has been built in the “hot lake” crater, which is the current focus of activity. The ash cone is surrounded by a small moat of water.

It is likely that in the short term, activity will alternate between dry and wet eruptions. When drier conditions prevail, like last week, some volcanic ash may be produced. If there is an increase in water near the vent then phreatic (steam driven) eruptions may occur. The crater containing the lava dome remains unchanged.

Seismic tremor levels are currently low, which is thought to partly reflect the lack of water involvement in the current activity. A gas flight on 26^th February measured around 600 tonnes per day of SO₂, and 1950 tonnes per day of CO₂, similar to other measurements made since the start of 2013.

White Island remains in a heightened state of unrest and the long term outcome of the unrest remains unclear. It could lead to explosive eruptions and larger ash emissions, like in August 2012, or decline to background activity. In the short term it is expected that activity will be variable, largely reflecting the influence of water on the style of activity.

GNS Science continues to closely monitor White Island through the GeoNet project.
Volcanic Alert Level has changed from 2 to 1
Aviation Colour Code has changed from Orange to Yellow

Photo showing the White Island craters. The main steam and gas plume is coming from the ash cone occupying the previous hot lake crater. The small lake to the north is the cool lake (temp approximately 40C) and the lava dome crater is partially hidden under the steam plume to the left of the cool lake.

Background
Unrest at White Island began in July 2012, leading to explosive eruptions and ash emissions in August. A small lava extrusion occurred in November, followed by phreatic, steam driven activity in December which continued through January and February 2013. Minor ash emissions have been interspersed throughout this eruption sequence as conditions within the craters have changed.

The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano. Level 1 indicates signs of volcanic unrest.
Aviation Colour Codes are based on four colours and are intended for quick reference only in the international civil aviation community.

White Island 25/02/2013

VOLCANIC ALERT BULLETIN: WI – 2013/10

White Island Volcano
Volcanic Alert Level 2
Aviation Colour Code: Orange
4pm Monday, 25 February 2013

White Island update:
Volcanic unrest continues

Over the weekend the style of activity at White Island changed, the active vent began producing ash. The island was visited today and the ash emission has ceased, being replaced by steam and gas explosions from the active vent.

The level of volcanic tremor has increased, associated with the reappearance of fluids in the vent area. This change in activity is consistent with the level of unrest we have seen over the last month at the island.

The current episode of activity started in August 2012 (explosions and ash emission) followed in November 2012 by extrusion of a small lava dome. Elevated but not high unrest followed. Volcanic unrest again increased at White Island in mid-January and continues. This unrest was been manifested as increased hydrothermal activity in the ‘hot lake’ which has now developed into an active vent area. This is some of the most vigorous activity seen at White Island for many years.

GNS volcanologist Brad Scott who visited the island today commented “the unrest continues and we continue to see small scale explosive events. Larger explosive eruptions can occur at any time with little or no warning. As always a high level of caution should be taken, if visiting the island”.

The outcome of the unrest remains unclear; it could lead to explosive eruptions and ash emissions, like in August 2012 or decline away. The state of unrest at White Island is relatively static at present, with no clear signs of an increase or decrease in activity.

GNS Science continues to closely monitor White Island through the GeoNet project.

Background
The GeoNet project is funded by EQC and provides monitoring for all of New Zealand’s volcanoes.
http://www.geonet.org.nz/volcano/info/whiteisland
http://www.gns.cri.nz/Home/Learning/Science-Topics/Volcanoes/New-Zealand-Volcanoes/White-Island

VOLCANIC ALERT BULLETIN: WI – 2013/8

White Island Volcano
Volcanic Alert Level: 1
Aviation Colour Code: Yellow
1:30 pm Monday, 11 February 2013

Ash Hazard for Aviation at White Island Reduced:
Aviation Colour Code Lowered to Yellow; Volcanic Alert Level Unchanged at 1

Following analysis of recent changes and measurements from White Island, GNS Science assessed that the likelihood of eruptions that might affect aviation is now lower than last week. The Aviation Colour Code has therefore been reduced from Orange to Yellow. The situation at White Island remains changeable, the overall eruption hazard is similar to recent weeks and the Volcanic Alert Level remains at 1.

Early last week the level of volcanic tremor recorded at White Island dropped to less than half that of the week before. At the same time small explosive eruptions in the active crater that had been occuring for about three weeks lessened in intensity. GNS Volcanologist Brad Scott who observed the activity last Friday said “The area that was earlier erupting has now filled again with water and the only activity is small geysering. But the lake remains hot, about 80 deg C.”.

Sulphur Dioxide (SO2) and Carbon Dioxide (CO2) flux measurements on February 7 were very similar to measurements in January, with 560 tonnes per day of SO2 and 1800 tonnes per day of CO2.

The substantial variations in activity over the last few weeks are signs that the situation at White Island remains very changeable and hazardous explosions may possible at any time with no warning.

VOLCANIC ALERT BULLETIN: WI – 2013/7

White Island Volcano
Volcanic Alert Level: 1
Aviation Colour Code: Orange
5 pm Thursday, 31 January 2013

Minor increases in gas flux at White Island

Data from a gas-measuring flight undertaken yesterday at White Island by GNS scientists shows that levels of volcanic gases emitted from volcano are slightly higher than the levels measured last week.

Overnight, the seismic activity has reverted to a continuous tremor and remains at a high level.The Volcanic Alert Level remains at 1 and the Aviation Colour Code remains at Orange.

Volcano Technician Karen Britten said that although there appeared to be a muddy lake around the active vent, the area looked quite dry. During yesterday’s flight she saw many explosions from the vent, but they were “not as visually spectacular” as those she observed last Friday.

Carbon Dioxide (CO2) gas flux has increased from 1800 to 2000 tons per day, Sulphur Dioxide (SO2) flux from 366 to 600 tons per day and Hydrogen Sulphide (H2S) flux is now 19 tons per day (previously, 15 tons/day). GNS scientists say it is quite likely that the increases in sulphur gases are caused by re-heating and movement of elemental sulphur in the hydrothermal system surrounding the new magma beneath the crater.

The higher gas fluxes do not suggest that a large eruption is imminent, but both the ongoing eruption of ash and rock and the strong seismic tremor indicate that White Island is still at an elevated state of unrest. The rapid changes during the past few days are signs that explosions are possible at any time and could occur with little or no warning.

Screen grabs from video footage taken 29 January 2013. Imagery supplied by Ron Haydon.

VOLCANIC ALERT BULLETIN: WI – 2013/6

White Island Volcano
Volcanic Alert Level 1
Aviation Colour Code: Orange
11.30 am Wednesday, 30 January 2013

White Island Update; small tuff cone forming

The ‘hot lake’ has now dried out and a small tuff cone has started to form on the former floor of the lake. The active vent continues to produce vigorous bursts of mud, rock, steam and gas from 50-100 m high. Ash is not being carried into the plume. This activity is intermittent as is the seismic activity. Current activity is not sufficient for Volcanic Alert Level 2.

GNS Science’s past monitoring of the island shows that new eruptive episodes often develop out of this type of activity. Small muddy lakes sometimes form in craters, as the unrest develops geysering and explosions occur through these lakes, becoming more vigorous with time. Larger explosions of mud, rock and perhaps molten sulphur are always possible and occur with little or no warning. A greater than usual hazard does exist for visitors to the island as a result of the current level of volcanic activity.

This morning the gas and steam plumes appear to have declined, judging from the various web camera images available. A gas flight is being conducted to day to ascertain if the volcanic gas flux has changed since Friday.

GNS Science continues to closely monitor White Island through the GeoNet project.
The Volcanic Alert Level remains at 1 and the Aviation Colour Code remains at Orange.Background

Images of the steam driven activity in the small lake at White Island. Photo by Brad Scott. See video below.

VOLCANIC ALERT BULLETIN: WI – 2013/5

White Island Volcano
Volcanic Alert Level 1
Aviation Colour Code: Orange

1pm Tuesday, 29 January 2013

Recent change in seismic activity at White Island

Early this morning the continuous volcanic tremor which has been recorded during the few weeks at White Island has changed to a pattern of intermittent tremor. When occurring, the volcanic tremor remains strong. The current level of unrest means that there is a greater than usual hazard to visitors.

The crater lake is drying out and the frequent bursts of mud, steam and gas are still vigorous. During the last few days, the bursts have thrown mud and rock several tens of metres out from the lake area. Steam and gas clouds above the volcano are often visible from the Bay of Plenty coastline.

GNS Science’s past monitoring of the island shows that weak ash eruptions have often followed drying out of this type of mud-filled lake. More vigorous explosions of mud, rock and perhaps molten sulphur are possible in future with little or no warning. The current level of unrest means that there is a greater than usual hazard to visitors.

The amounts of volcanic gases measured last week were similar to those measured in December 2012 and do not suggest a large eruption is imminent. However, both the on-going mud bursts and the strong seismic activity indicate that White Island is still at an elevated state of unrest.

GNS Science continues to closely monitor White Island through the GeoNet project.

The Volcanic Alert Level remains at 1 and the Aviation Colour Code remains at Orange.

VOLCANIC ALERT BULLETIN: WI – 2013/4
White Island Volcano

Volcanic Alert Level 1
Aviation Colour Code: Orange
5pm Friday, 25 January 2013

No increase in degassing at White Island

A gas flight was undertaken this morning at White Island by GNS scientists. It showed a level of gas emitted from volcano similar to that of December 2012. Mud geysering is continuing in the crater lake and earthquake activity remains above background.

A gas flight was undertaken this morning in good conditions. Carbon Dioxide (CO2) flux was 1800 tons per day, Sulphur Dioxide (SO2) flux was 366 tons per day and Hydrogen Sulphide (H2S) flux was 15 tons per day. These values are similar to that from the last gas flight survey on 19 December 2012. Observations during the flight revealed that the mud geysering in the main crater lake is still vigorous.

While the new gas data do not suggest any sign of imminent large eruption, both the ongoing mud geysering and the increased seismic activity indicate that White Island is still at an elevated state of unrest.

Future eruptions are possible with little or no warning. The level of unrest does mean that there is an increased hazard to visitors.

GNS Science continues to closely monitor White Island through the GeoNet project.

The Volcanic Alert Level remains at 1 and the Aviation Colour Code remains at Orange.
The GeoNet project is funded by EQC and provides monitoring for all of New Zealand’s volcanoes.

VOLCANIC ALERT BULLETIN: WI – 2013/3
White Island Volcano

Volcanic Alert Level 1
Aviation Colour Code: Changed to Orange
4pm Thursday, 24 January 2013

White Island update: Volcanic unrest increases, aviation colour code changed

Over the last 20-30 hours the style of seismic activity at White Island has changed. The level of volcanic tremor has started to decrease, but hybrid volcanic earthquakes have appeared. Hybrid earthquakes are typically associated with the movement of molten material (magma) within an active volcano. This change in activity is consistent with an increase in the level of unrest; hence the Aviation Colour Code has been lifted to Orange.

The current episode of activity started in August 2012 (explosions and ash emission) followed in November 2012 by extrusion of a small lava dome. Elevated but not high unrest followed. However, volcanic unrest has been increasing at White Island since about January 14. This unrest has been manifested as increased hydrothermal activity in the ‘hot lake’ and has been described as some of the most vigorous activity seen at White Island for many years.

GNS volcanologist Gill Jolly commented “Visitors to White Island are now at the highest level of risk since the start of the 2012 eruptions. Hazards to visitors can include the health effects of volcanic gas exposure, including respiratory issues, skin and eye sensitivity to acid gases. Explosive eruptions can occur at any time with little or no warning. We advise a high level of caution should be taken, if visiting the island”.

The outcomes of the unrest could be either the passive intrusion of magma to shallow deeps with no changes in surface activity, more dome building as in November 2012 or explosive eruptions and ash emissions, like in August 2012.

The state of unrest at White Island is increasing and future eruptions are possible with little or no warning.
The increased level of unrest does mean that there is an increased hazard to visitors.

GNS Science continues to closely monitor White Island through the GeoNet project. Weather permitting a ‘gas flight’ will be made tomorrow morning to ascertain if there have been any changes in the gas flux from the volcano.

Background
Hybrid volcanic earthquakes are so called because they are a mix of rock fracturing and magmatic vibration. They are thought to represent the movement of magma in a volcano.

Aviation Colour Codes are based on four colours and are intended for quick reference only in the international civil aviation community.

The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano. Level 1 indicates signs of volcanic unrest.

The GeoNet project is funded by EQC and provides monitoring for all of New Zealand’s volcanoes.

http://www.geonet.org.nz/volcano/info/whiteisland
http://www.gns.cri.nz/Home/Learning/Science-Topics/Volcanoes/New-Zealand-Volcanoes/White-Island

Contact:
Brad Scott,
Duty Volcanologist: Phone 07 3748211

VOLCANIC ALERT BULLETIN: WI – 2013/2
White Island Volcano

Volcanic Alert Level 1
Aviation Colour Code: Yellow

10am Tuesday, 22 January 2013

Volcanic Unrest increases

GNS Science Volcanologist Brad Scott visited White Island yesterday to assess the increased level of volcanic unrest.

Mr Scott’s observations confirmed that hydrothermal activity in the small 'hot lake' has increased. The most common activity is doming up of the lake surface by steam/gas, bringing large amounts of sediment to the surface, often with vivid white steam/gas 'flashing' from around the base. Every so often stronger events happened. This activity has been increasing since late 2012 and is now semi continuous.

GNS volcanologist Brad Scott said “the hydrothermal activity is some of the most vigorous I have seen at White Island for many years. This type of activity usually leads to stronger volcanic activity and is a significant concern.”

The lava dome that was first observed in late November has not changed since the last
observations on the 1st January 2013.

Seismicity continues to show elevated levels of volcanic tremor and this is likely generated by the processes driving the vigorous hydrothermal activity in the lake.

The state of unrest at White Island is increasing and future eruptions are possible with little or no warning. The increased level of unrest does mean that there is a hazard to visitors. Past activity indicates that eruptions, such as that which occurred on 5 August 2012, could occur with little or no warning, even when the Alert Level is 1 (volcanic unrest). Caution should be exercised when visiting the island.

GNS Science continues to closely monitor White Island through the GeoNet project.

Background
The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano.
Level 1 indicates signs of volcanic unrest.
Aviation Colour Codes are based on four colours and are intended for quick reference only in the international civil aviation community.

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