GeoNet News
EXPLORING THE GEONET PROJECT
Volcano monitoring
Tongariro
White Island
Monowai submarine volcano
Volcano gas flights
ISSUE 17 – FEBRUARY 2013
GeoNet News
EXPLORING THE GEONET PROJECT
Inside
INTRODUCTION
FEATURES
Volcano monitoring
ISSUE 17 – FEBRUARY 2013
3
Tongariro4
White Island
6
Monowai submarine volcano
8
Volcano gas flights
9
Our team watching the
volcanoes10
Cover image
Eruption column viewed from
Emerald Lakes, Te Ma-ri.
www.geonet.org.nz
Over the last few months, we have seen our volcanoes grab the geological
hazards spotlight. This has kept the GeoNet volcanology team very busy in
monitoring the activity and providing the best possible advice to the public
and to key stakeholders.
In this issue of GeoNet News, we present some of the many different
aspects of volcano monitoring and research. The science that is needed
to fully understand how volcanoes work is by necessity multidisciplinary:
volcanic activity produces seismic signals, it changes the way the ground
deforms, it changes the chemistry of water on and inside the volcano and it
results in emissions of gas. GeoNet monitors all these parameters and then
synthesises the data so we can build numerical and conceptual models
of how the volcanoes are behaving – and ultimately develop a forecast of
what will happen next.
With volcanoes, however, we are dealing with highly unpredictable
phenomena: even with the world class volcano monitoring technology that
we have installed through GeoNet, it is simply not possible to say when a
volcano will erupt with any precision. Instead, as we learn more about the
volcanic activity, we can improve our forecasting: we can provide better
estimates of the likelihood of different possible future scenarios.
To provide the most comprehensive assessment of volcanic hazard,
GeoNet calls on a wide range of volcanic specialists around the country. In
the universities and in the Crown Research Institutes and other government
agencies, there is a wealth of quality expertise that helps to provide in-depth
understanding of the monitoring data. GeoNet scientists are at the core of a
volcano crisis response and have the responsibilities of changing volcanic
alert levels, but the skills and advice provided by other science groups
is invaluable. As an example, the science co-ordination for the Tongariro
eruptions has been a truly “all-of-New Zealand” team effort.
By necessity, the subjects covered in this issue of GeoNet News are only a
brief snapshot of how we keep track of volcanic activity, but I hope that you
will get an appreciation of the complexity of the work that GeoNet does to
provide timely advice to all New Zealanders.
GeoNet is a non-profit project operated by the
Institute of Geological & Nuclear Sciences Limited
(GNS Science) with core funding from the
Earthquake Commission. It involves GNS Science
building and operating a modern geological hazards
monitoring system for New Zealand.
The GeoNet project started in 2001. It provides
real-time monitoring and data collection for
rapid response to and research into earthquakes,
volcanic eruptions, tsunami and landslides.
Data collected by GeoNet are available free of charge.
Visit www.geonet.org.nz for more information.
Gill Jolly
Head of Volcanology Department
VOLCANO Monitoring
Volcano monitoring is based on the
assumption that molten rock (magma)
will move from deep beneath a volcano
to shallow levels within the volcano. This
has to occur before any eruption can
start and this movement of magma is
often detectable using various methods.
Volcanologists use many techniques to
monitor an active volcano; some of the
main techniques are seismic monitoring,
ground deformation, and water and gas
chemistry.
As the molten material moves it creates
seismic signals; some can be from rocks
breaking as space is created or just from
the gas and steam being given off from
the magma passing through the rocks. If
enough magma accumulates at shallow
depth it may deform the ground above it,
and we may see this in the GPS data.
Growing
magma body
As the molten rock and associated gases
react with the ground water they create a
geothermal system and we can look at the
chemistry of this. Each volcano is different
so we may not be able to apply all our
technologies at every volcano.
Contact: Brad Scott
Email: [email protected]
Cracking
generates
earthquakes
In this image you can see the magma (orange) which moves into the volcano to generate volcanic
earthquakes and change the shape of the volcano.
geonet scoops computer awards
The Australia and New Zealand Internet Awards (ANZIA) are an annual
event celebrating the achievements of organisations, businesses and
individuals that have made significant contributions to the development
and use of the Internet in Australia and New Zealand.
In Canberra at the awards ceremony in
October GeoNet won the Information
category – initiatives that bring information,
knowledge and materials online. ANZIA
commented that:
“The judges agreed that their GeoNet Rapid
initiative is of critical public importance in
New Zealand. The project makes
earthquake information available rapidly –
within 5 minutes – through the web and is
being used extensively by third party
applications including smart phone apps.
The importance of the initiative to scientists,
geologists, communities and at a personal
2 – GeoNet
Displaced surface
after inflation
level is very significant. It has helped
citizens to engage with and understand
what the earthquake data is telling us.
Whilst the judges believe the data and
information has undoubted relevance to
the international scientific community, it is
at the individual and personal level that it
is probably most significant.”
The New Zealand Open Source Awards
2012 were presented on November 7.
They recognise and promote the
contributions of New Zealanders to
free and open source projects and
philosophy. GeoNet proudly won two
awards on the night:
• Use of Open Source software in
Government: our nomination was for
GeoNet Rapid, our state-of-the-art, fast
and innovative earthquake location and
information system that is a key
component of the GeoNet Project.
• Use of Open Source software in
Science: our nomination was for
GeoNet’s Open Data policy, which
makes all data and information freely
available to all.
In both cases the foundations for the
initiatives were laid many years ago by
people with foresight and dreams; GeoNet
would like to acknowledge all who have
played their part along the way to get
GeoNet to where it is today.
Contact: Sara Page
Email: [email protected]
GeoNet – 3
Background image:
North view of Tongariro showing steam
and gas plume from Te Ma-ri vents.
TONGARIRO
Tongariro is a complex of multiple volcanic cones constructed
over a period of 275,000 years. The active vents include Te Ma-ri,
Emerald Lakes, North Crater and Red Crater. There were at
least five reported eruptions from the Te Ma-ri craters between
1855 and 1897 but since then they had been dormant until 2012.
On July 20 the Volcanic Alert Level was
raised to Level 1, indicating volcanic unrest
and the possibility of eruptive activity. At
Tongariro volcano we have a seismic
network, GPS receivers and regular
chemistry is done of selected hot springs
and fumaroles (steam vents). It was data
from this seismic network and chemistry
that enabled us to recognise the change
in status at Tongariro (Te Ma-ri).
The major changes were an increased
level of seismic activity, reflected in both
the type of earthquakes occurring and
their locations; this was followed by
changes in the amount of volcanic gas
and the composition of these gases.
These changes confirmed that new
molten material was present at depth
and gases were reaching the surface,
both clear signs of volcanic unrest.
Based on these changes we added extra
seismic sites around Te Ma-ri, a GPS
receiver and we increased our gas
sampling and monitoring.
At 11:52pm on 6 August there was a short
phreatic eruption at the Te Ma-ri craters
area. Explosions at a new vent area below
the Upper Te Ma- ri crater threw blocks of
lava, up to 1 metre in size, out more than
1.5km. These created impact craters in
the ground and caused damage to the
Ketetahi hut on the Tongariro crossing.
The eruption also caused a flow of rock
and soil debris which partially filled a
stream valley.
4 – GeoNet
Eruption fissures.
View along the
eastern rift,to central
fumaroles and Upper
Te Ma-ri Crater.
November 21 eruption from our Te Ma-ri crater camera.
A second eruption then occurred at
Te Ma-ri on 21 November 2012 – this lasted
for around 5 minutes with an ash column
and plume being ejected 3-4km above the
Upper Te Ma- ri crater.
Although we were able to recognise and
had responded to the original volcanic
unrest, the data we were getting did not
provide a short term warning of either of
the eruptions, reinforcing the unpredictable
nature of volcanoes.
geothermal system and creating a mixed
geothermal-magmatic system. Instability
within this system is driving the eruptions.
In early 2013, the Te Ma-ri craters continue
to be active with continuous emissions of
steam and volcanic gas.
Contact: Steve Sherburn
Email: [email protected]
As analysis continues of the eruptions to
date, we can conclude they are driven by
the ‘new’ molten material reaching shallow
depths under Te Ma-ri. It is reacting with the
GeoNet – 5
White Island
White Island has been New Zealand’s most
active volcano over the last 37 years. It has
been in a state of volcanic unrest over that
entire period (Alert Level 1).
The volcano has also spent hundreds of days
in eruption during that time. We deploy a
variety of monitoring and research techniques
on the island including continuous data from
a seismograph, GPS, gas scanner and gravity
meter, supplemented by regular water and gas
chemistry, gas flights, deformation levelling
and soil gas surveys.
In July last year, rapid changes in lake
level were noticed and volcanic gases
and tremor increased leading to a short
eruptive episode from August 1 - 12.
During that time two craters were active
within the crater lake and a small tuff
cone was built. On August 5 there was
a small night eruption which was caught
on our cameras. A few days later on
August 7 the first ash emissions were
produced from White Island since 2000.
Activity was quiet until December when
a spiny lava dome was documented
growing in a crater formed by the
August eruption.
Lava domes are usually formed by
magma that has lost most of its gases
so that it is very sticky. This causes the
magma to pile up over the volcanic
event and form a dome. Lava domes are
common at some volcanoes, but have
never been seen before at White Island.
Magma last reached the surface at
White Island in 2000. At that time it
erupted explosively as molten rocks
called volcanic bombs, rather than
forming a dome.
6 – GeoNet
At White Island there
is always some indication
of molten material at
shallow depth; this is
reflected in the
deformation levelling as
the ground heights change,
and in the seismic activity
and gases.
A close-up view of the dome. The dome is made
of thick, relatively cool and congealed lava and has
prominent spines. The dome is about 20 – 30 metres
across. In the foreground is a small, warm lake.
Crater floor with people circled to show scale.
The amount of gas the volcano is
producing varies with the levels of
activity. On clear days a gas and steam
plume will be seen above the volcano
from the mainland.
In 2013 the state of unrest at White Island
has again increased with vigorous
hydrothermal activity, which often leads to
stronger volcanic activity. Future eruptions
are possible with little or no warning.
Contact: Brad Scott
Email: [email protected]
Hydrothermal action, January 2013!
The August 5 night-time eruption.
GeoNet – 7
MONOWAI SUBMARINE VOLCANO
Monowai eruption effects as viewed by an RNZAF flight.
Submarine volcanoes exist all the way from
New Zealand to Tonga. About 400km north of
Raoul Island is Monowai, with a summit about
120m below sea level. This is one of our more
active submarine volcanoes. When in eruption
the discharges from the volcano discolour the
sea, sometimes for several kilometres around
the volcano.
During an eruption the volcano produces
a unique type of seismic signature, called
a T-wave. These travel very efficiently in
water and we are able to record them
on our seismograph in Rarotonga in
the Cook Islands about 2000km away.
They are also well-recorded in French
Polynesia by the seismic network
operated there. Hence we are often
aware when the volcano is in eruption.
During 2009 activity was noted in multiple
months based on seismic data recorded
in Rarotonga. On October 28 an RNZAF
flight over the area confirmed the activity,
observing discoloured sea water related to
suspended sediment and precipitates (see
above photo).
In June 2012 seismic activity indicated
that eruptions were again occurring at
Monowai and this was confirmed by more
discoloured sea water in the area from an
RNZAF flight on June 3.
Contact: Brad Scott
Email: [email protected]
8 – GeoNet
VOLcANO GAS FLIGHTS
Locations of Monowai and Havre volcanoes.
Also in the Kermadec Islands is
the Havre submarine volcano.
After a large pumice raft was
identified in early August,
analysis of remote sensing
data has shown that this came
from a submarine eruption at
Havre on July 18-19 2012.
Flights between Auckland and Apia
in early August reported seeing the
floating pumice near Raoul Island,
it was about 280km long. The
GeoNet duty volcanologist received
this information from the MetService
Aviation Forecaster as part of the
routine exchange of volcano data
and observations between the
organisations and airline pilots.
Later in August the RNZAF mapped
the extent of the pumice raft, which
started near Raoul Island and now
extended over 600km to the north-east
and was over 70km wide. The HMNZS
Canterbury also sailed through it
enroute to Raoul Island and reported it
was up to 0.6m thick. In November
2012 it started to arrive in Tonga.
Recent gas flux flight at White Island showing a very visible plume.
Gas flights are done routinely at our active cone
volcanoes. We load five different instruments
into a Piper Seneca plane, which measure gas
concentration. GPS instruments record exactly
where we are in space and determine the wind
speed and direction.
Recent gas flux flight at White Island showing
the increased activity in the crater.
These flights take between 2.5 and 3
hours and eventually, after downloading
data from the on-board logger and some
complex data processing, give us sulphur
dioxide, carbon dioxide and hydrogen
sulphide flux data. We routinely get data
from Ruapehu, White Island, Ngauruhoe
and more recently Tongariro.
Gas flux data make a significant
contribution to our volcano assessments.
Flights are done more frequently when
the volcano is erupting, in order to help
ascertain whether the volcano is ramping
up or quietening down.
The weather plays a huge part in our
ability to fly over the Tongariro National
Park volcanoes and there are very few
suitable flying days to be had.
Contact: Karen Britten
Email: [email protected]
Our local Piper Seneca. GeoNet commissioned
the plane’s door which has been engineered
and certified to have instruments poking out
through it to gather the gas data.
GeoNet – 9
OUR TEAM WATCHING THE VOLCANOES
GeoNet has a large team of volcano experts;
here are the faces of the people (mostly based
at Wairakei) that do the hard work and science
behind the scenes to keep an eye on our
active volcanoes.
Gill Jolly
Volcanologist; Head of
Department: Volcanology
Bruce
Christenson
Senior Volcanic Fluids
Geochemist
Art Jolly
Karen Britten
Senior Volcano
Geophysicist
Volcano Geochemistry
Technician
Mike Rosenberg
Steve Sherburn
Nico Fournier
Craig Miller
Volcanologist
Senior Volcano
Geophysicist
Volcano Geodesist
Volcano Geophysicist
Joan Fitzgerald
Agnes Mazot
Tony Hurst
Geoff Kilgour
GeoNet Geochemistry
Laboratory Assistant
Volcanic Gas Geochemist
Senior Volcano
Geophysicist
Scientist - Volcanology
Coming up...
Dave Keen
GeoNet Network
Operations Technician
Richard
Johnson
GeoNet Network
Operations Technician
Fiona Atkinson
Brad Scott
Emergency Management Summer Institute
GeoNet Network
Operations Technician
Volcanologist
When: 11-15 March 2013
Where: Massey University Campus, Wellington
Contact:[email protected]
Web: disasters.massey.ac.nz
10 – GeoNet
GeoNet – 11
Recent additions to the network
Our regular wrap-up of the new stations added to the GeoNet
hazard monitoring network, constructed by our team of
technicians at Avalon, Wairakei and Christchurch.
February 2012
RGHD Continuous GPS at Hawthornden near
Lake Rotorua
OKCZ Seismic stations on Banks Peninsula,
AKCZ one above Okains Bay and the other above Akaroa Harbour
TRTS Continuous strong-motion recorder
installed in Torrens Terrace, Wellington
March 2012
EYCZ Regional seismic site at the Eyrewell
Geomagnetic Observatory in
mid-Canterbury
July 2012
Four temporary seismic and a continuous GPS receiver were installed on Mount Tongariro in response to
increased volcanic activity on July 22
August 2012
Contact details
GeoNet website: www.geonet.org.nz
Email: [email protected]
Address: GNS Science, PO Box 30-368,
Lower Hutt 5040, New Zealand
Editor: Sara Page
GeoNet News is published twice yearly.
Additional copies are available, at no cost
for domestic delivery, from Leanne Dixon,
GeoNet Administration Coordinator
Email: [email protected]
Phone: +64 4 570 4888
Articles published in this newsletter
may be quoted or reproduced as long as
GNS Science is acknowledged as the source.
GNS Science retains copyright on photographs,
diagrams and illustrations and reproduction may
only occur with prior written approval.
HORN
Two
SAGENZ (Southern Alps Geodetic
Experiment
New Zealand) continuous
BNET
GPS sites near Mount Cook National
Park at Mount Hodgkinson
and Cox’s Downs
were upgraded
INHS
Main funding agency:
A strong-motion site at
Inglewood High School
April 2012
PNRS Strong-motion installations in Roslyn
School,
Palmerston North, Seatoun
SEAS
School,
Wellington and in Christchurch:
HUNS
Huntsbury, Mairehau Primary School,
MPSS
Ouruhia School, Sumner, Opawa OHSS
School, Moorhouse Avenue and
SUMS Kilmore Street
RGHD
OPWS
INHS
MORS
KILS
May 2012
STAS
Strong-motion instrument at St Albans
in Christchurch
June 2012
RACZ
AMCZ
Regional sites in Canterbury near Rakaia and Amberley
MENS Strong-motion sites in Christchurch
at
Menlo Terrace (Mount Pleasant) and
DHSS
Diamond Harbour
PWES
TOTS
Strong-motion sites in Wellington at
Porirua West and Totara Park
CPIB
Building sites in the Christchurch
Polytechnic Institute of Technology
completed and made operational
12 – GeoNet
TRTS
PWES
SEAS
TOTS
AMCZ
EYCZ
HORN
BNET
RACZ
OKCZ
AKCZ
HUNS
KILS
MPSS
STAS
OHSS
CPIB
SUMS
MENS
OPWS
DHSS
MORS
Lead organisation in the GeoNet project
ISSN 1176-0567 (Print) ISSN 1178-4201 (Online)
PNRS