New Zealand volcanoes activity – White Island and Mt. Tongariro (August 6 and August 7)

Last update: August 10, 2012 at 9:32 am by By

This is Part 2 of the New Zealand volcanoes activity report

CLICK HERE TO READ THE LATEST NEWS

You may follow also Facebook Volcano PageGoogle+ VolcanoesTwitter : @VolcanoReport
Read also : (31/7 – 05/08)  – (06/08 – 07/08) -

This page is an archive page of activity reporting of the New Zealand volcanoes. As our main article becomes too long, we need to cut off some parts for easier reading and for Internet traffic bandwidth reasons.
Best Webcams : White Island Crater Rim and White Island Crater (1 image every 30 minutes) – Mt Tongariro (1 image every 15 minutes). If you know about a better one, please inform us and we will include it here


Update August 7 – 23:15 UTC - Mt Tongariro
- What looked this morning as clearing weather has become again overcast with poor to no visibility on the webcams.
- Based on the seismogram at West Tongariro, no more activity has been noticed.
- As mentioned before, ski infrastructure is open and New Zealanders are enjoying the fresh snow. Mt. Tongariro is far enough away from the ski runs to ski safely.
- VAAC Wellington reported at 17:28 UTC that a faint ash cloud was visible in satellite imagery along the eastern periphery. Level of a possible ash cloud is reported as 20000 ft (6000 m). As the ash is to the east of the island most air traffic will have no problems at all and passengers may even get a great image of an active volcano if the weather would improve
- GNS Science and Geonet have no more bulletins published since yesterday
- Ash is currently being analyzed. Results may give a clue in what really happened inside the volcano. Analysis have also to confirm that no fresh magma was present in the ash.
- The YouTube video below describes the volcano’s status on Wednesday morning New Zealand time.

VAAC Wellington volcanic ash previsions at August 8 00:20 UTC - image courtesy and copyright Metservice NZ

Update August 7 – 19:29 UTC
- The ITN video below shows the volcano yesterday with a thick cloud deck.
The current weather is much better and we expect far better footage within a couple of hours

Update August 7 – 18:35 UTC
- A very calm volcano. the West Tongariro seismogram shows almost no activity the last 24 hours.
- The weather looks to improve, so we have a good chance to see the steam plume the next 12 hours (almost daylight in New Zealand now)

Seismogram shows a calm volcano at 06:31 local time - image courtesy Geonet and GNS Science

Update August 7 – 08:40 UTC
The beauty of nature. A great picture as taken by Driftwood Eco-Tours the morning after the eruption. The sky is still full with gases and ash and the sun reflects beautifully!

Driftwood Eco-tours wrote : This was what the sunrise looked like this morning from our deck showing reflected light of the Tongariro ash cloud - image copyright and courtesy Driftwood Eco-tours

Update August 7 – 08:23 UTC
-At 19:48 local time (07:48 PM) a relatively strong earthquake (volcanic ?) was noticed on the seismogram. Such earthquakes may show a new phreatic eruption, but this has to be confirmed by locals or by the scientists. The webcams at either volcanoes in the area are showing a black screen and poor to no visibility.

Update August 7 – 08:03 UTC
- NZherald writes that locals have criticized the response to last night’s Tongariro eruption as too slow but authorities have defended their procedures, saying they quickly established there was no immediate risk and put plans in place. At ER we think that the authorities did a great job in informing the people from the very beginning of the crisis. Among other notes we wrote in the beginning that locals were downplaying the risk of a possible eruption as almost non-existent and only harming the local tourist industry!
- VAAC Wellington released a report for aviation that the ash cloud was no longer visible on satellite imagery (which is normal as the volcano was only emitting mainly steam clouds)
- Some people have asked us what Aviation color Orange exactly means : Volcano is exhibiting heightened unrest with increased likelihood of eruption. Or: Volcanic eruption is underway with no or minor ash emission
- The video below from Weather-watch New Zealand is very interesting as it also gives some non-weather facts.

Update August 7 – 07:22 UTC
- The volcano looks to be silent on the seismogram for more than 8 hours now

Seismogram at 07:35 UTC at West Tongariro - image courtesy Geonet and GNS Science

- Geonet and GNS Science published the following communiqué just after noon NZ time :
A short lived phreatic eruption occurred at the Te Māri craters area on Mount Tongariro at approximately 11:50 pm Monday local New Zealand time (Monday, August 6). Activity at the present time consists of steam clouds and some small earthquakes. Eruptive activity is low level but could recommence at any time.
Observations of Mount Tongariro this morning by GNS Science are that eruption activity has subsided. White steam clouds were observed at the historically active Te Māri craters area but poor weather conditions at the time obscured a direct view of the active vent(s). There have been no lahars or pyroclastic flows or lava flows.
Our analysis of seismic data is that there was an explosive eruption lasting only a minute or two, followed by a series of discrete small earthquakes over the next few tens of minutes. No volcanic tremor occurred in the days preceding the eruption, nor has any occurred since then.
It is too early to predict the next series of events, but we expect heightened activity may continue for several weeks. There are likely to be specific signals of future magma movement beneath the volcano and we continue to monitor the situation through the GeoNet volcano-seismic network of instruments.
As with any volcano, an eruption could occur at Tongariro at any time with little or no warning and there is an elevated level of risk, particularly on the northern slopes and valleys of the mountain.
Ash samples collected near Lake Rotoaira last night will be tested and analysis of seismic data continues. GNS Science volcanologists are continuing to monitor the eruption and are working with Massey and Canterbury universities collect samples for analysis, as conditions permit. Further information will be released as soon as it is available.
- The ashfall prediction refers to possible ongoing activity following the Tongariro eruption last night at 11:50 pm. GNS Science volcanologists are monitoring the eruption and further information will be released as soon as it is available.
- Some reports in the media are based on misinterpretation of Geonet and GNS Science reports. Volcanologists have said that the volcano erupted without warning. This is of course true and not true. Those people (like ourselves) were alerted by Geonet and GNS Science since the awakening of the volcano (based on seismicity and chemical analysis). The only thing volcanologists surprised was that there were no elevated seismic signals or harmonic tremor recorded just before the phreatic eruption (Phreatic eruptions typically include steam and rock fragments; the inclusion of lava is unusual.)

Predictad ashfall of a Tongariro eruption at 12:00 Tuesday August 7 - Eruption model = volume of 0.001 km3 at a height of 10000 ft (3 km) (

- The video below shows the amount of ashfall on the roads near the volcano. Most of the ashfall comes from the first 10 minutes of the eruption.


Update 23:42 UTC : Wellington VAAC (Organization who is informing aviation about problematic volcanic ash concentration in the air) sends regular reports to the airlines. The first reports were talking about volcanic ash up to 20000 ft (6 km).

Update 23:19 UTC : The nearby ski slopes are staying open as they are located at another volcano. The 3 Tongariro volcanoes have no linked magma system and scientists and police have not asked the operators to stop working. What a thrilling ski experience !

Update 23:12 UTC : We see some activity at the moment, nit visually as the webcams only show a cloud cover, but the seismograms shows regular volcanic earthquakes and limited tremor

Update 23:00 UTC : State Highway One has re-opened. Flights to the immediate volcano area have been canceled but all other flights are scheduled to depart without too many problems.

Update 22:48 UTC : The seismogram shows again some higher tremor the last 10 minutes (2 periods). More of these peaks may be expected the following hours.

Image shows tremor at 22:40 UTC - mages courtesy Geonet and GNS Science

Update 22:47 UTC : GNS Science has said that the current activity may last for hours, days, weeks, months or even longer. Translated into human terms, nobody knows how the volcano would behave.
Some roads have been blocked as a precaution. People living in the direct vicinity are told to keep their windows closed.
At present no evacuations have been ordered and are not likely to be called because of the location of the volcano and the active vents.

Image from Peter Drury at Stuff.co.nz - Click on this image to see other pictures

Update 22:35 UTC : A series of great images like the one at right has been published by Stuff.co.nz. Click here to watch them all.

Update 22:09 UTC : Mount Tongariro is a popular hiking destination and searchers are checking huts this morning.
Volcanic ash is being reported as far as Napier (100km distance). Quantities of up to five cm are being reported in some places. Truck driver Brynn Rodda was driving near the mountain when it erupted and has told Radio New Zealand it was a spectacular sight. “I could see this big cloud, it looked like a fist basically, at an angle a across the sky, and at about the wrist section of the fist, there was a sudden, orange ball of flash,” he said.
Incandescent material was seen by a number of people, but so far we have seen no pictures of the eruption. Some people who reported the action are talking about a “new” crater at the side of the volcano, which means that a new vent may have been opened.
The seismogram shows harmonic tremor during approx 12 minutes, which may have been the time the volcano spewed a lot of ash (see image below).

Update 21:02 UTC : As the activity at Mt Tongariro may continue for a while, we will start an in-depth article which will only carry information for the New Zealand volcanoes.

Light flashes at the volcano at the tme of the eruption

Update 20:55 UTC : Police were alerted to the eruption shortly before midnight by a member of the public who reported seeing “flame-like explosions” and a cloud of ash coming from “a new hole in the side of the mountain”.
As the weather is still very bad, we have to rely on the seismographs to detect eventual new eruptions. Based on the seismogram we think the volcano is silent again with perhaps one smaller explosion 45 minutes ago.

Update : The volcano alert level has been increased to 2 and the Aviation Color code to Red.
The volcano can be seen in the webcam, however the current bad weather shows only raindrops and clouds

GNS Science and Geonet reported just a little while ago that :
An eruption occurred at Tongariro at approximately 11:50 pm (Monday, August 6). GNS Science volcanologists are monitoring the eruption and further information will be released as soon as it is available. (a lot of thanks to ER reader Kukido for informing us)
The eruption and the Harmonic Tremor can well be seen on the graph below. When you want to follow seismicity at Mt Tongariro on the live seismograph, click here

Mt Tongariro Ashfall after first eruption since 1897! - Image courtesy Geonet and GNS Science

Seismogram showing very clearly the eruption at Mt Tongariro

 


August 5, 2012

Small eruption at White Island Volcano

The White Island web camera has captured a small eruption on Sunday morning local time (August 5 04:55 am NZST or August 4 16:55 UTC) from the Crater Lake at White Island. During the past week there has been an increase in volcanic tremor and volcanic gas levels.
Overnight Friday July 27 to Saturday July 28 the lake level in the Crater Lake at White Island rose by about 3 m to 5 m. 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.
Since early July there have been intermittent periods of volcanic tremor, becoming more continuous since July 28. A particularly stronger episode was recorded overnight August 4 – 5, and ended in a volcanic earthquake at 04:54 am NZST. Examination of the images from the Factory webcam between 04:54 am and 04:57 am on August 5 have revealed an eruption from the Crater Lake, nicely lit by the moon (see photo sequence below).
These phenomena are not unknown for White Island, but this is the first substantial confirmation that small scale eruptions are now occurring on the island and confirms the risk to visitors has increased.
White Island is an active volcano and there is always risk when visiting the island. Eruptions can occur at any time with little or no warning. We advise extra caution should be taken if visiting the island.
GNS Science volcanologists are monitoring the activity and further information will be released as soon as it is available.
The alert level of the volcano was raised from 1 to 2 (on a scale of 0 to 5).

Eruption at White Island on August 5 2012 - Image courtesy Geonet and GNS Science

 

White Island volcano New Zealand - RSAM and SSAM graph - image courtesy Geonet and GNS Science

Mount Tongariro volcano

The volcanic earthquakes continue beneath Mount Tongariro, but have declined in size and number. No other changes have been observed.
The sequence of volcanic earthquakes recorded at Mount Tongariro since July 13 has continued, but now there are fewer than 5 events each day and most are smaller than those in July (see graph below). Activity is currently at a lower level than in previous weeks, but may increase again at any time. The earthquake locations cluster in a zone beneath northern Tongariro (Emerald Lakes – Te Māri craters) at 2 km-7km depth.
No other changes have been observed. Initial analysis of the July gas samples confirmed that there had been a marked increase in the volcanic gas component of fumarole discharges at Tongariro. Full analysis of these samples continues.
We are planning field visits next week to retrieve data from the portable seismometers that were deployed across the mountain in late July. We also plan to repeat a survey of soil gas flux survey in the next few weeks. GNS Science volcanologists are monitoring the unrest and further information will be released as necessary.

Seismicity at Mt Tongariro - Image courtesy Geonet and GNS Science

 


August 3-4, 2012

New Zealands shaky attitude towards earthquakes and volcanoes
On Thursday, there was breaking news out of GNS Science after volcanologists determined that a recent increase in activity meant the aviation alert level needed to be lifted over White Island. The volcano’s alert level remains the same, but the increase in activity means pilots should be on a slightly higher alert in case a small eruption shoots ash and rock into the sky above this well offshore volcano. But this raised alert level follows hot on the heels from the decision to lift Mt Tongariro’s alert level up to one a couple of weeks ago, after a swarm of small quakes there. The two are unrelated confirms GNS. Read more …


August 2, 2012

Crater Lake at White Island has recently started to re-fill and gases are now vigorously streaming through it. Airborne gas measurements made yesterday show that the discharge of some sulphur gases has increased. During the past few weeks there has also been some minor volcanic tremor.
During 2011 and early 2012 White Island Crater Lake slowly evaporated to expose steam vents and form two large muddy pools. However, sometime between Friday July 27 and Saturday July 28, the lake level rose quickly by about 3 m to 5 m. Vigorous flow of gas and steam through the new lake can be seen from the air. Two photos at the end of this bulletin, taken from a similar position, clearly show the change in water level.

The lake has been inaccessible for many months and we have not been able to measure changes in its temperature or chemistry. Sulphur gases measured yesterday in the steam and gas plume have increased during the last three months but CO2 gas output remains at about the same level.
Since early July there have been intermittent periods of volcanic tremor, including several hours early on Saturday July 28 and during Monday and Tuesday this week. Tremor is not uncommon at White Island but earlier this year it had been at very low levels.
A recent ground survey showed that the main crater floor is no longer subsiding and now may be slowly rising.
These phenomena are typical for White Island’s activity, but are the first substantial changes to occur in the last few years.
White Island is an active volcano and there is always risk when visiting the island. Eruptions can occur at any time with little or no warning. The recent changes in activity suggest that the hydrothermal system has become unstable, and as a result the risk has increased. We advise extra caution should be taken, especially if approaching the Crater Lake and other active thermal features.
GNS Science volcanologists are monitoring the activity and further information will be released as soon as it is available.
The increased activity at White Island has no connection with the recent earthquakes and changes in gas flux at Tongariro volcano.
Alert Level remains at 1; Aviation Colour Code changed to Yellow
Image and text courtesy GEONET New Zealand and GNS Science


July 31, 2012

99 volcanic earthquakes since July 11 at Mt. Tongariro volcano, New Zealand

GNSC science volcanologist Michael Rosenberg published a rather extensive report on the current Mt. Tongariro volcano activity earlier today.

As part of our routine monitoring, we have recorded a sequence of volcanic earthquakes at Mount Tongariro since July 13, peaking in activity on July 20, and now numbering 3-10 per day, as shown on the graph below. The earthquakes cluster in a zone between Mount Tongariro and the eastern side of Lake Rotoaira at 2-7 km depth. These are very small earthquakes and unlikely to be felt by people.

To better understand the significance of these earthquakes and if volcanic unrest is developing at Mount Tongariro we have recently:

  • conducted more sampling of selected springs and fumaroles and completed some chemical analyses;
  • installed a GPS instrument to detect possible ground movement.

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 kilometers 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.

Text and graphics courtesy Geonet and GNS Science

Rodger Wilson said in his daily volcano activity overview : Seismicity at Mt Tongariro volcano (New Zealand) has returned to low levels, but numerous small events are evident on seismic records there.


Speak Your Mind

*

Desktop Version