The Volcano space is using the Blog Mode!
View this blog in blog mode

Volcanic Alert Bulletin WI 2016/07:
8:50am Wednesday 25 May 2016; White Island Vol
cano 

Alert Status:
Volcanic Alert Level
 remains Level 1
Aviation Colour Code
remains Green

The level of volcanic unrest at White Island declined following the eruption. Volcano seismic activity has decreased, while the gas output has been variable and is now at typical background levels. No further eruptions have occurred and the Volcanic Alert Level remains at Level 1. GNS staff visited White Island (Whakaari) last week to continue their evaluation of the eruption impacts, sample gases, collect thermal IR images and undertake maintenance of monitoring equipment affected by the eruption on April 27.

Thermal IR images have established very high temperatures are present on a mound in the back of the 1978/90 Crater. This is the same area where a dome grew in 2012. There are two areas of hot gas output and the temperatures ranged from 292 to 337 ºC. These are the highest temperatures we have measured since early 2014 when we measured 450 ºC in the same area. The April 27 eruption removed about 13-15 m of lake floor sediments and now a new lake is starting to form at this lower level on the floor of the crater; the temperature is 49 ºC. The temperature of Fumarole 0 (the largest accessible one) has increased from 178 to 188 ºC.

Observations during this visit of the eruption deposits confirm the explosive nature of the April 27 eruption and the complexity. The eruption did produce very energetic blasts and surges. In places it sheared off or broke survey pegs and markers at ground level. Typical of energetic blast and surge events, the deposit is not very thick, ranging from a few mm to 50 mm in thickness. Ballistic blocks were observed in several locations, suggesting more than one source for them. There is also a ‘wet’ surge deposit that is mainly made up of lake floor sediments (muds, sands and sulphur). It is starting to appear the eruption sequence was: the area around the former Donald Duck Crater collapsed and exploded, then the former lake and the sediments in its basin have been erupted forming the blast and surge deposits. This has lowered the lake floor at least 13 m. This was a very energetic phase with both surge and ballistic phases (some post surge). Following this there has been collapse of the 1978/90 Crater walls. Survivability during the eruption would most likely have been low in areas of the Main Crater floor.

 

The level of volcanic unrest at White Island (Whakaari) declined quickly following the eruption on April 27. The Volcanic Alert level for White Island remains at Level 1. Aviation Colour Code remains Green. GNS Science volcanologists continue to closely monitor White Island through the GeoNet project.

Steve Sherburn
Duty Volcanologist

Media Contact:
Brad Scott
Volcanologist 

phone 07 3748211





 

Volcanic Alert Bulletin RUA 2016/05:
3:00pm Tuesday 17 May 2016; Ruapehu Vol
cano 

Alert Status:
Volcanic Alert Level
 remains Level 2
Aviation Colour Code
remains Yellow

 

Mt Ruapehu remains in a state of volcanic unrest. The temperature of the summit Crater Lake has declined slightly and is now 39 ºC, down from a high of 46 ºC. Moderate levels of volcanic tremor continue. Analysis of water samples collected last week show no change in lake chemistry. The Volcanic Alert Level remains at Level 2 (moderate to heightened unrest). The Aviation Colour Code is also unchanged, being Yellow.

Recent visits to the volcano have measured an increase in the output of volcanic gas. When the weather conditions allow we will be repeating these to see if this continues. The analysis of water samples from the Crater Lake show little change from the previous samples. This implies the Crater Lake geothermal system has not responded to the recent increase in gas and heat through the lake. Moderate levels of volcanic tremor continue and the lake temperature measured by the outlet data logger is now 39 ºC. Some of the decline is caused by rainfall/snow into the lake.

Data available at present indicates volcanic unrest continues at Mt Ruapehu. When weather conditions allow we will be collecting further data. The volcanic alert level for Mt Ruapehu is Volcanic Alert Level 2 (moderate to heightened unrest). The Aviation Colour Code is Yellow.

GNS Science volcanologists continue to closely monitor Ruapehu through the GeoNet project.

Art Jolly
Duty Volcanologist

Media Contact:
Brad Scott
Volcanologist 

phone 07 3748211

 

This week the Volcanic Alert Level (VAL) for Ruapehu was raised to Level 2.

Why did we change the VAL? We based the change on the observation of changes in three parameters we monitor: lake temperature, seismicity (earthquakes) and gas output.

The NZ Volcanic Alert Level system ranges from Level 0 to Level 5. Volcanic Alert Level 2 is defined as ‘moderate to heightened volcanic unrest’ this basically means that the signs of life at the volcano are stronger, and that there is a higher likelihood of an eruption. BUT, and this is the tricky bit: volcanic unrest does not always lead to an eruption. While Volcanic Alert Level 1 is ‘minor volcanic unrest’ - meaning there are signs of life at the volcano, the likelihood of an eruption is small. However, our volcanoes can skip right past Volcanic Alert Level 2 and go straight to Volcanic Alert Level 3. This happened on the 27 April, when White Island went from 1 (minor unrest) to 3 (minor eruption).  

About our monitoring

Our volcano monitoring team base their decision on the VAL on how they think the molten material (magma) or its associated gas and fluids are interacting under the volcano. These interactions can produce changes or symptoms that we can measure (e.g. heat flow, seismicity, ground deformation, gas or chemistry changes). The signs of unrest may be more intense than in Volcanic Alert Level 1, or the interpretation of monitoring data by the team more strongly indicates the movement of magma or its associated fluids. There may be a higher likelihood of an eruption than at Volcanic Alert Level 1.  A volcano can be at Volcanic Alert Level 2 for months, years or even decades.

Why we changed the VAL for Ruapehu

Given the higher lake temperatures, higher gas output and increased seismic activity, we made a call that the mountain had increased its activity to VAL 2. While at the top end of the level we could have steam and gas driven events (geysering) within the Crater Lake, we are not there at the moment.  In the coming days or weeks, we could see activity increase or decrease. If it did increase it would be exciting to see the signs of activity, including steam and gas driven events (geysering) within the Crater Lake! These have often before at Ruapehu (1966-68; June 1978; January-April 1980: February 1982 and May-June 1985). These geysers make for some spectacular viewing but we don’t recommend being too close to the lake should these occur.

Is Ruapehu safe?

It is an active volcano and we should always respect our beautiful mountain. However, although the Volcanic Alert Level has been raised this doesn’t mean you have to avoid the Tongariro National Park. Yes there is a higher likelihood of an eruption developing, however volcanic unrest does not always led to an eruption. Eruptions only affect the summit area of Ruapehu and a few selected valleys. The summit hazard zone defined by DOC should be respected. The public are safe visiting all the normally accessible areas like the visitor centres, cafes, ski fields, lodges, huts, Tongariro Alpine crossing and other lower altitude walks.

NZ Volcanic Alert Level system

In July 2014 the Volcanic Alert Level system used in New Zealand was updated, following a review. One of the big changes was the introduction of two levels to define volcanic unrest (levels 1 and 2). Being able to distinguish between these two levels of unrest was an important part of the need for a change in the Volcanic Alert Level system and is entirely due to advances in volcano monitoring made by the GeoNet project (thanks EQC).

VOLCANIC ALERT BULLETIN: RUA – 2016/04
11:45 am Wednesday 11 May 2016; Ruapehu Volcano

Alert Status:
Volcanic Alert Level
 is raised to Level 2 (change from 1)
Aviation Colour Code raised to Yellow (change from Green)

Recent visits to the volcano have confirmed an increase in the output of volcanic gas from Mt Ruapehu’s Crater Lake. Moderate levels of volcanic tremor continue and the lake temperature measured by the outlet data logger is 45 ºC. The increase in gas output, the high lake temperature and continued seismicity suggest that Ruapehu is at a higher level of volcanic unrest. As a result, GNS scientists revise the Volcanic Alert Level to Level 2 (moderate to heightened unrest). The Aviation Colour Code is also changed, from Green to Yellow.

We made two monitoring visits to Mt Ruapehu yesterday, one was a gas flight to measure the gas output and the other was to sample the Crater Lake water and make additional ground based gas measurements. Volcanic gas measurements indicate an increase in the amount of both carbon dioxide (CO2) and sulphur dioxide (SO2) output. The ground based gas measurements were complimentary to the airborne data.

Seismic activity at Mt Ruapehu is usually dominated by volcanic tremor. Since the volcanic earthquakes in late April the seismicity has been dominated by volcanic tremor at varying levels. The level of tremor has increased but is not exceptional in terms of the last few years.

The temperature of the Crater Lake as measured by a data logger near the outlet has been rising and since mid-April 2016 and has risen from 25 °C to 46 °C.  For the last couple of days it has ranged between 45 and 46 ºC.

Taken together these data now indicate more volcanic unrest at Mt Ruapehu. The increased gas output coupled with high heat flow and volcanic tremor imply a higher likelihood of activity. At this time these changes at Ruapehu are considered sufficient to change the Volcanic Alert Level. The volcanic alert level for Mt Ruapehu is now raised to Volcanic Alert Level 2 (moderate to heightened unrest). The Aviation Colour Code has also changed, from Green to Yellow.

GNS Science volcanologists continue to closely monitor Ruapehu through the GeoNet project.

 

Geoff Kilgour
Duty Volcanologist

 

Media Contact:
Brad Scott
Volcanologist


07 3748211

On Wednesday, 27 April 2016 a moderate steam and gas driven eruption occurred at White Island (Whakaari). The eruption ejected the Crater Lake, created a new crater, generated landslides/collapse and excavated some of the Crater Lake floor. This generated a very energetic blast that covered much of the Main Crater floor and the north eastern portion of the volcano with green tinged ash. This eruption occurred during a period of volcanic unrest, however we were challenged initially to confirm it had happened. These steam and gas driven events do not give any useful warning.

Detecting the eruption

To confirm there has been an eruption you need 2-3 definitive pieces of data; typically in volcanology that is seismic and acoustic recordings of the ‘explosion’, maybe ground deformation and  visual observations. The April 27 eruption at White Island challenged us on all of these, mainly because it happened at night in an isolated area.

The best data are usually the seismic and acoustic (air pressure waves from explosions), however seeing it happen cannot be beaten. This eruption occurred around 9.30-10 pm and no one was on the island. We recorded a complex pulse of seismic data that lasted about 1½ hours, starting around 9.31 pm. The largest and most energetic portion was at around 9.53 pm, suggesting the eruption climaxed about then. The size of the signal was also ‘small’ compared to past activity (2011-2013), and the acoustic signals were not clear, and were difficult to interpret.

Our gas sensors only work in day light, and need the gas plume to be over them. The web cameras also work best in daylight, although they can gives useful images at night, especially when there is a bright moon. What we didn’t know on the evening was that the blast deposit obscured our web camera on the north rim, so even as the sun came up we still couldn’t see to confirm the activity. Nothing very definitive to work with here, hence we couldn’t confirm the eruption on Wednesday evening.

In hindsight, we now have great images from the NZ MetService rain radar that shows an eruption plume reaching to 3 km by 9.52 pm and over 4 km at 10:00 (It takes 7 minutes for the rain radar to collect a full image). The GPS on the Main Crater floor didn’t record any ground deformation, however there is an apparent ‘shift’ which starts around 9.30 pm and continues to 10.24 pm which we now believe was the antenna losing signal or been coated by ash. Detailed post event processing also shows there are acoustic Signals but they remain inconclusive.

Confirming the eruption

As the day light grew on Thursday morning we were able to see from the Factory camera (Dino) there was an indication of a new deposit. Later in the morning, we also noted that two of our solar panels didn’t start to charge batteries, detected via our battery monitoring systems, suggesting they were covered in ash.

We knew something had happened but it wasn’t until GNS volcanologists flew over the volcano in the afternoon they were able to fully appreciate the impacts of the previous night’s eruption. A dark yellow-green ash deposit from the eruption covered about 80% of the floor of Main Crater, blasted high up the sides of the crater wall on both the north and south sides. At a distance of 500 m from the eruption site the ash deposit is about 5 mm thick. It extended off the island to the north east.

Impacts and Hazards

The surge deposit obscured our web camera on the north rim, the crater floor GPS , along with all of the solar panel arrays. GNS didn’t consider it safe to visit the Main Crater floor however staff did service the equipment outside of that area to ensure valuable monitoring data continued to reach our volcanologists.

The eruption deposit at the North rim site was typical of what volcanologists refer to as a hot volcanic surge deposit.  It was plastered on sides facing the vent, but was absent on shaded/protected surfaces. This indicates the surge travelled horizontally, across the crater floor, so the ash did not fall from the sky as often occurs. It has a texture like ‘apple crumble’ and was very dry, this indicates it was very hot when deposited. Survivability during the eruption would have been low on much of the crater floor.

 

 

Questions about White Island (Whakaari) that you were too afraid to ask

So, last Wednesday evening, White Island erupted with no warning. Not a huge event. However the eruption had a really big impact on the island. We are still making sense of all the data we have got so far and are yet to examine the Main Crater floor in detail due to the risk to our staff. We’ve put together some of the questions we’ve been getting asked as well as some questions that haven’t been asked yet, but we think are important. Right, first up:

Q. What’s up with that green ash? Is that mineral makeup?

No, thanks Twitter. It is NOT mineral makeup. That amazing green colour was created from a unique combination of minerals on White Island. The ash contained quite a bit of pale yellow sulphur which appeared as irregular shaped lumps, and some translucent golden yellow grains. This is consistent with the colour of the deposit.

Q. Was there any juvenile material found in the ash?

No. The reason we test for juvenile material is to determine whether there was new magma (lava) coming up OR whether this was older material. New material could indicate that this would have been the start of a whole new phase of activity for White Island; however, in this eruption it only tossed out old lake sediments and crater wall material.

For people who want more science, here it is:

The volcanic blast deposit collected from the North rim site solar panel was found to have no new juvenile material. Most of the ash is strongly hydrothermally altered old rock fragments, with some fresher fragments of volcanic glass and crystal. However these are attached to or form a partial coating of white to pale grey hydrothermal altered material. From our past experience of examining White Island ash we are confident that this is not April 2016 magma (new stuff.

When no juvenile material is found, this means that new magma was not involved in the eruption.

Q. If people were hanging around the crater during the eruption, would they have survived?

We are really happy the eruption happened at night. The blast would have been travelling fast and was hot hence survivability during the eruption would have been low in many areas of the crater.

Q. What can you tell us about this new vent?

During the visit on Thursday afternoon we obtained some thermal images of the crater area, and during the aerial inspection on Friday to measure the gas output we had better views of the 1978/90 Crater area. From the photography and thermal images we were able to identify the location of a new vent that had erupted on Wednesday evening. Significant collapse had also occurred in this area, formally known as Donald Duck Crater (in no way related to Dino). Several meters of Donald Mound have collapsed into the 1978/90 Crater area, taking away our target that was used to calibrated measurements from our web camera images. It had been repainted only 6 days before.

Q. Are we going to call this new vent Venty McVentface?

No. Not even once. Stop asking us that, Reddit. We are much more boring, we go for month/year so we can keep track of them ... once you have 20-30 vents with cool names it becomes a challenge!  We have had some great ones; Orca, Gilliver, Rudolf, Donald Mound, Christmas, Noisy Nellie, RF, PJ, TV1, Blue Duck, Donald Duck (when Donald mound and Blue Duck joined), Big John, GIBRUS, just to name few along with the boring ones like 1931, 1971, 1978/90. 

Q. Why did the Volcanic Alert Level get lowered so quickly?

Following the eruption the volcano did not start to produce volcanic ash from any of the active vents. The seismic activity remained at relatively low levels and gas emission data indicated SO2 output was at levels similar to those prior to the eruption. As a consequence of the continued lack of activity after the eruption, the Volcanic Alert Level was lowered to Level 2 on Thursday evening. This indicated that the volcano was not erupting but remained in a state of moderate to heightened volcanic unrest.

Q. What’s going to happen next with White Island (Whakaari)?

That’s the $64 million question!. White Island is by far one of our most active volcanoes. Heightened volcanic unrest continues at White Island (Whakaari) and no eruptions have occurred since April 27. Volcanic gas output and seismic activity which is dominated by volcanic tremor increased in 2011 when volcanic unrest developed. That led to the eruptions in 2012 and 2013. These two unrest parameters remain elevated and have defined a ‘new background’. The possibility of further eruptions remains high and the Volcanic Alert Level remains at Level 2 (moderate to heightened volcanic unrest).

White Island can and does continue to intrigue us, providing us rich scientific data that increases our understanding of volcanoes in New Zealand and around the world. We aren’t entirely sure what the volcano will do next. 

 

Volcanic Alert Bulletin WI 2016/06
12:00 pm Monday 9 May 2016  

Alert Status: White Island Volcano

Volcanic Alert Level 1 (changed from Level 2)

Aviation Colour Code Yellow (unchanged) 

The Volcanic Alert level for White Island has been lowered from Level 2 to Level 1.

Aviation Colour Code remains Yellow. 

 The level of volcanic unrest at White Island (Whakaari) has declined following the eruption on April 27. Both volcanic gas output and seismic activity have decreased. Visual observations from a flight on Friday and seismic observations confirm no further eruptive activity has occurred.

 Volcanic Alert Level 1 indicates minor volcanic unrest continues.

 

Geoff Kilgour

Duty Volcanologist

 

Media Contact

Brad Scott

7 3748211

 

Volcanic Alert Bulletin RUA 2016/03:
3:30pm Saturday 7 May 2016; Ruapehu Vol
cano 

Alert Status:
Volcanic Alert Level
 remains Level 1
Aviation Colour Code
remains Green

This afternoon at around 2pm a tourist flight over the Crater Lake observed vigorous steaming of the lake surface and a disturbance of the lake surface, upwelling bubbles. Although not seen in recent years this has been observed in the past when the temperature rises over 40-42 °C.

The Crater Lake temperature appeared to have reached a maximum on May 3 at 42 °C, however since then the lake has heated to 44 °C. This is the hottest lake temperature we have recorded since the new lake was established post 2000.

The swarm of volcanic earthquakes reported in RUA 2016/02 (3 May) has stopped. However the GeoNet seismic network at Ruapehu continues to record volcanic tremor. The level of volcanic tremor has increased slightly this week, but is at levels lower than those reached in April 2015 when the lake was also heating. Volcanic tremor is always present at Ruapehu, and the level does vary a lot. Research suggests volcanic tremor is linked to both hydrothermal and magmatic processes at Ruapehu and not necessarily an indication of an upcoming eruption. 

We will provide more information as it becomes available.

Brad Scott
Duty Volcanologist

Media Contact:
phone 07 3748211

 

Volcanic Alert Bulletin RUA 2016/02:
10:15am Tuesday 3 May 2016; Ruapehu Vol
cano 

Alert Status:
Volcanic Alert Level
 remains Level 1
Aviation Colour Code
remains Green

The volcanic earthquake swarm which intensified at Mt Ruapehu around April 25-26 is now declining and the Crater Lake temperature has peaked at 42 °C. A short period of moderate volcanic tremor was recorded on Monday afternoon.  Mt Ruapehu remains at Volcanic Alert Level 1 (Minor volcanic unrest).

Since April 25-26 we have been recording a volcanic earthquake swarm beneath the Crater Lake of Mt Ruapehu. The number of events and size has now declined. Swarms of volcanic earthquakes like these are uncommon on Ruapehu in recent years. Seismic activity at Mt Ruapehu is usually dominated by volcanic tremor. A period of moderate volcanic tremor lasting about an hour was recorded from 13:10h on Monday 2 May.

The temperature of the Crater Lake has been rising and since mid-April 2016. It has risen from 25 °C to 42 °C and is now equal to the highest recorded since 2011. The temperature appears to have reached a maximum and no increase has been recorded in the last day.

Currently we are uncertain of the implications of the recent observations. However at this time these changes at Ruapehu are not considered insufficient to change the volcanic alert level. The volcanic alert level for Mt Ruapehu remains at Volcanic Alert Level 1 (Minor volcanic unrest).

GNS Science volcanologists continue to closely monitor Ruapehu through the GeoNet project.

 

Brad Scott
Duty Volcanologist

Media Contact:
phone 07 3748211

Volcanic Alert Bulletin WI 2016/05:
1:00pm Monday 2 May 2016; White Island Vol
cano 

Alert Status:
Volcanic Alert Level
 remains Level 2
Aviation Colour Code
lowered from Orange to Yellow

The Aviation Colour Code has been lowered from Orange to Yellow. The Volcanic Alert Level remains at Level 2. Heightened volcanic unrest continues at White Island (Whakaari). No eruptions have occurred since 27 April. Gas output is slightly elevated but within the range of recent measurements. Seismic activity remains low.

Visual and seismic observations confirm no further eruptive activity has occurred at White Island (Whakaari). During an aerial inspection on Friday the location of the vent that erupted on Wednesday evening was confirmed.

Remote gas measurements confirm no significant change in the long-term gas output from the volcano. Volcano earthquake activity remains low.

There is currently no indication that activity is either increasing or decreasing at White Island. The heightened state of volcanic unrest remains (Volcanic Alert Level 2). GNS Science volcanologists are continuing to monitor the volcano and further bulletins will be released as required.

Brad Scott
Duty Volcanologist

Media Contact:
phone 07 3748211

 

Volcanic Alert Bulletin WI 2016/04
10:45 am Saturday 30 April 2016; White Island Volcano

Alert Status:
Volcanic Alert Level
 remains Level 2
Aviation Colour Code
remains Orange

Heightened volcanic unrest continues at White Island (Whakaari). During an aerial inspection on Friday the site of Wednesday’s eruption was seen for the first time; a new crater has formed in the north east corner of the 1978/90 Crater Complex.  Gas output is slightly elevated but well within the range of recent measurements. Preliminary analysis of the eruption deposit suggests that no or little new magma (lava) was ejected. Seismic activity remains low. The Volcanic Alert Level remains at Level 2.

During an aerial inspection on Friday to measure the gas output and photograph the active crater area it was possible to confirm the location of the vent that erupted on Wednesday evening. A new crater has formed in the north-east corner of the 1978/90 Crater Complex.  No vent was visible in this area before Wednesday. Significant collapse has occurred around the area and post-eruption landsliding is also present. Hot translucent gas has been emitted from the new vent.

The gas measurements confirm no significant change in the long-term gas output from the volcano. Volcano earthquake activity remains low.

Laboratory analysis of the eruption deposit collected from the web camera site on the north rim has confirmed that most of the ash is strongly hydrothermally altered old rock material. No evidence of new, juvenile magma was found. This suggests that no new lava material has been erupted and that the eruption was likely driven by steam and gas, like the eruptions in 2012 and 2013.

There is currently no indication that activity is either increasing or decreasing at White Island. The heightened state of volcanic unrest remains (Volcanic Alert Level 2). GNS Science volcanologists are continuing to monitor the volcano and further bulletins will be released as required.

Agnes Mazot
Duty Volcanologist

 

Media Contact:

Brad Scott
Volcanologist

Phone 07 3748211

 

Volcanic Alert Bulletin RUA 2016/01:
3:30pm Friday 29 April 2016; Ruapehu Vol
cano 

Alert Status:
Volcanic Alert Level
 remains Level 1
Aviation Colour Code
remains Green

Over the last few days there has been a volcanic earthquake swarm at Mt Ruapehu. The Crater Lake temperature is now 40 °C. Mt Ruapehu remains at Volcanic Alert Level 1 (Minor volcanic unrest).

Since April 26 we have been recording a volcanic earthquake swarm beneath the Crater Lake of Mt Ruapehu. Swarms of volcanic earthquakes like these are uncommon on Ruapehu in recent years. Seismic activity at Mt Ruapehu is usually dominated by volcanic tremor.

The temperature of the Crater Lake has been rising since late 2015 and since mid-April 2016 the Crater Lake temperature has risen from 25 °C to 40 °C. Similar temperatures and rate of temperature increase were observed in March 2011, April 2014 and February 2015.

We have not noted any changes in other monitored parameters like volcanic gas, lake chemistry or lake overflow.  A gas flight was performed on March 30 and the Crater Lake was sampled on April 14.

Currently we are uncertain of the implications of the recent observations. However at this time these changes at Ruapehu are not considered sufficient to change the Volcanic Alert Level.

GNS Science volcanologists continue to closely monitor Ruapehu through the GeoNet project.

The changes at Mt Ruapehu are not related to the volcanic eruption that occurred at White Island on Wednesday 27 April.

Agnes Mazot
Duty Volcanologist

Media Contact:

Brad Scott
Volcanologist 

phone 07 3748211

 

Volcanic Alert Bulletin WI 2016/03:
6:45pm Thursday 28 April 2016; White Island Vol
cano 

Alert Status:
Volcanic Alert Level
 is lowered to Level 2
Aviation Colour Code
remains Orange

Based on new observations, the Volcanic Alert Level for White Island has been lowered to 2 from 3. This indicates that the volcano is not erupting anymore but remains in a state of moderate to heightened unrest. The Aviation Colour Code remains at Orange.

An eruption occurred at White Island at about 9:50 pm yesterday (Wednesday, 27 April 2016). No further eruptive activity has been observed since yesterday evening. Seismic activity remains low and new gas emission data for today show a SO2 (sulphur dioxide) flux level similar to that prior to the eruption. As a consequence of the continued lack of activity since the eruption on Wednesday evening, the Volcanic Alert Level has been lowered to Level 2.

A more precise time for the eruption, about 9.50 pm, has been inferred from a combination of data from yesterday evening’s seismic activity, a MetService rain radar image, and data from a GPS receiver on the island.

GNS volcanologists flew over White Island this afternoon to assess the impacts of last night’s eruption. A dark-green ash deposit from the eruption covers at least 80% of the floor of Main Crater, and up the sides of the crater wall on both the north and south sides. At a distance of 500 m from the eruption site the ash deposit is about 5 mm thick. The green colour is due to minerals on the ash.

There is currently no indication that activity may be building up at White Island. However, GNS Science staff will not be visiting the main crater floor until further notice due to the heightened state of volcanic unrest. GNS Science volcanologists are continuing to monitor the volcano 24/7 using existing instrumentation on the island and occasional measurements made from safe distance. Further bulletins will be released as required.

Agnes Mazot
Duty Volcanologist

 

Media Contact:
Brad Scott
Volcanologist 

phone 07 3748211


 

See pictures on our Twitter feed.

Volcanic Alert Bulletin WI 2016/02:
11:33am Thursday 28 April 2016; White Island Volcano

Alert Status:
Volcanic Alert Level
raised to 3 
Aviation Colour Code
changed to Orange

An eruption occurred at White Island (Whaakari) sometime between 9:30 – 11:00 pm yesterday (Wednesday, 27 April 2016).

As a consequence of this activity the Volcanic Alert Level is now raised to Level 3 (Minor Volcanic Eruption) and the Aviation Colour Code to Orange.

No eruptive activity has been seen since about 11:00 pm yesterday.

The eruption that occurred Wednesday 27 April was accompanied by a moderately elevated seismic activity. The seismic activity is now back to normal.

The eruption appears to have deposited material over north side of the crater floor and up onto north crater wall.

There is not yet a clear view of crater area visible from cameras.

GNS Science volcanologists are monitoring the volcano and further information will be released as soon as it is available.

 

GNS Science continues to closely monitor all our active volcanoes through the GeoNet project. The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano. Aviation Colour Codes are based on four colours and are intended for reference only in the international civil aviation community.

Contact: Agnes Mazot
Duty Volcanologist
07 3748211

Volcanic Alert Bulletin WI 2016/01:
11:00am Wednesday 27 April 2016; White Island Volcano 

Alert Status:
Volcanic Alert Level
 remains Level 1
Aviation Colour Code
 
remains Green

Routine monitoring of White Island (Whakaari) indicates minor volcanic unrest continues. Over the last couple of weeks GNS scientists have observed a fall of 2 m in the water level of the Crater Lake. However they have not noted any changes in other monitored parameters like the amount of volcanic gas being emitted, fumarole temperatures and the presence of volcanic tremor or earthquakes.  

During a visit last week by GNS volcanologist Brad Scott he was able to confirm the lake level has dropped 2 m in the last 2 weeks. The lake is now at about the same level it was in 2014. The drop in water level of the Crater Lake has revealed several islands or crater outlines and the lake temperature has increased 2 ºC (56-58 ºC) since February.

There has been a small decrease in the temperature of the hottest fumarole (169 to 161 ºC) since February. The SO2 gas output has ranged between 90 and 480 tonnes per day (1.0 to 5.5 kg per second) of gas during the last 5 weeks. These are typical values for White Island.

The level of volcanic tremor continues to vary, but remains below those observed in 2012 when unrest was stronger and small eruptions occurred.

The Volcanic Alert Level remains at Level 1 (minor volcanic unrest). The changes we are seeing presently are consistent with minor volcanic unrest. Typical volcanic unrest hazards like hot ground and gas remain. A range of activity can occur under these conditions with little or no useful warning.

GNS Science is continuing to closely monitor the activity at White Island (and other New Zealand volcanoes) through the GeoNet project.

 

Volcano information: Brad Scott
07 374 8211

 

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

 

Want to learn more about volcano monitoring?

http://www.gns.cri.nz/Home/Learning/Science-Topics/Volcanoes/Monitoring-Our-Volcanoes

Following the August 2012 eruptions from Te Maari large amounts of volcanic gas were emitted. Sometimes the output of sulphur dioxide (SO2) was over 5-8 kg per second (430-700 tons per day). However with time this decreased and we were not able to measure it from our standard airborne platform. We needed to find a new ground based technology. Based on our experiences from White Island (Whakaari) we chose to go with scanning FLYSPEC, a new version of the miniDOAS that we have at White Island. The new equipment has been installed collaboratively by DOC and GeoNet.  Data from this type of equipment is used by our volcano team to assess the status of the volcano and set the Volcanic Alert Level.

Volcanic gas is derived from the molten material (magma) that drives an eruption, so it is one of the few data that can give us direct information about the magma under an active volcano. The types of gas present and the amounts are very useful. Detecting and measuring gas is not easy. A correlation spectrometer (COSPEC) which was initially designed to measure industrial pollutants, are now routinely used by volcano observatories to measure volcanic gas emissions. The spectrometer is designed to measure the concentration of sulphur dioxide (SO2) in the volcanic plume that is emitted from the volcano. The miniDOAS and FLYSPEC are adaptions of this technology into smaller instruments. They work by analysing the ultraviolet light absorbed by the SO2 molecules in the volcanic plume. Hence we have to install them ‘under the plume’ to get data. The variable wind directions in NZ make this a challenge.

At Te Maari we have installed two scanning FLYSPECS to improve our chances of detecting the SO2 in the volcanic plume. When the local wind is blowing the gas plume over our instruments we are able to get data and work out how much gas is coming from the active vents. We get useable data about 40-50% of the time. Since September 2015 the gas output has dropped below 0.1 kg per second (8.6 tons per day) and is often just at the limits of detection. This is good for Tongariro National Park users as it confirms the volcano is slowly going back to sleep and risk from eruptions has decreased. 


GeoNet is a collaboration between the Earthquake Commission and GNS Science.

about | contact | privacy | disclaimer | mobile

GeoNet content is copyright GNS Science and is licensed under a Creative Commons Attribution 3.0 New Zealand License