GeoNet News
EXPLORING THE GEONET PROJECT
Teaching old DOGs new tricks
One year anniversary of the
Darfield 7.1 earthquake
Out in the field – building RTZ
Mitigating eruption risks - a look at
geothermal monitoring in New Zealand
Taranaki seismic upgrade completed
ISSUE 15 – OCTOBER 2011
GeoNet News
EXPLORING THE GEONET PROJECT
Inside
Editorial
Regulars
Editorial
2
Vital people in the GeoNet
project
11
Coming up...
11
Recent additions to the
network
12
FEATURES
Teaching old DOGs new tricks
3
One year anniversary of
the magnitude 7.1 Darfield
(Canterbury) earthquake
4
Out in the field - building RTZ
6
Social media
7
Mitigating eruption risks
- a look at geothermal
monitoring in New Zealand
8
Taranaki seismic upgrade
completed
10
Cover image
Helicopter delivering a load of concrete
to the RTZ site
www.geonet.org.nz
This issue comes out one year after the September 2010
‘Darfield Earthquake’. The day after that life-changing
event, GeoNet began its response in Canterbury
– and this continues today. We still have temporary
instruments set up around Canterbury and are currently
planning some new permanent sites as part of our
national network.
Although most of the team at GeoNet live in the North
Island, the people in Canterbury are on our minds
daily. Our technicians are frequently travelling down to
Christchurch to look after our equipment, back in the
office our data centre technicians are trawling through
the many aftershocks, and the team of duty officers
is on call 24/7 trying to get information on the bigger
aftershocks up on the website as soon as possible.
Although I spend most of my days in the office locating
earthquakes, I have travelled down to Christchurch,
once after the September event and more recently in
August to help replace some batteries at our temporary
sites. It is still hard to see how devastating earthquakes
can be in person, but the strength of the people is truly
uplifting. I see this daily through interaction on social
media and the emails we get via the website.
While we cannot change the past, nor predict the future,
we can improve how we get our data to the public and
scientific community.
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.
Sara Page
Editor
Email: [email protected]
– GeoNet
ISSUE 15 – OCTOBER 2011
earthquake Analysis – Teaching old DOGs new tricks
GeoNet has been trialling a new earthquake analysis system,
SeisComP3, which will reduce the time between feeling an earthquake
and reading about it on the website to a matter of minutes. The key
to this is automation, but there will be occasions when the Duty
Officer (GeoHazards) a.k.a DOG, will need to refine the earthquake’s
particulars, so the whole team has been ‘back to school’ to learn all
about the SeisComP3 package.
Above: Duty officer training session
Since the duty team was set up over
10 years ago, they have relied on being
alerted to significant earthquakes by
receiving pager messages. These look at
shaking data from all over New Zealand
and decide whether they are likely to be
at a level that might be felt by people.
The Duty Officer will then login to the
current CUSP earthquake analysis
system, review the earthquake P and S
wave arrivals and the amplitudes to
determine the location and magnitude,
and finally post the information to the
GeoNet website. The whole process
takes between 10 and 20 minutes,
depending on the complexity of the
earthquake. During this time an eager
public is already on the website hitting
their ‘refresh’ button, waiting for the
information to appear with the details
of the earthquake they just felt.
Above: Screenshot of the Beta website
So, how are we going to improve this?
GeoNet is going to run the SeisComP3
earthquake monitoring package. It was
initially developed by the German
Research Centre for Geosciences (GFZ)
in response to the Indian Ocean tsunami
of 2004 and is now maintained by Gempa
GmbH. It is designed to quickly locate
earthquakes and calculate their
magnitude using more modern
techniques than those of CUSP, and so
for the first time New Zealand will be
publishing earthquake details unreviewed
by a Duty Officer.
Dr. Bernd Weber of Gempa visited GNS
Science’s Avalon and Wairakei offices in
early August to run SeisComP3 training
courses for the Duty Officer team. Whilst
the whole point of SeisComP3 is to let
automatic processes work out the
answers, some earthquakes need to be
given a bit of a helping hand.
The Duty Officers have learnt the most
efficient way to get the best out of
SeisComP3 and how to sort out the
awkward cases.
What you will see over the coming year
is a ‘beta’ website featuring these rapid
automatic locations and magnitudes in
addition to the current manually-reviewed
ones. As we tune and improve SeisComP3
to work well in the New Zealand tectonic
setting there will come a point where it is
fit to take over the prime job of sending
out earthquake information to the
website. That will see the 20 minute wait
slashed to as little as two minutes for
earthquakes within New Zealand - that’s
18 valuable minutes for those whose job
it is to make the right response to
damaging shakes.
Contact: Kevin Fenaughty
Email: [email protected]
GeoNet – One Year Anniversary of the Magnitude 7.1 Darfield (Canterbury) Earthquake
On 4 September 2010 at 4:35 AM New Zealand time, the magnitude (M) 7.1
Darfield earthquake struck the Canterbury region. The epicentre of the
earthquake was located approximately 10km southeast of the town of
Darfield and 40km west of Christchurch (Figure 1), and caused a nearly
30km long surface rupture which has been named the Greendale Fault. It
was the most damaging earthquake in New Zealand since the 1931 M 7.8
Hawke’s Bay earthquake and was felt widely throughout the South Island
and lower North Island, with over 7300 felt reports received by GeoNet.
Christchurch experienced significant
damage due to shaking and liquefaction,
particularly to older brick and masonry
structures. In the year following the
Darfield earthquake, the Canterbury
region has experienced a large number
of aftershocks with GeoNet locating
more than 8100 to date (Figure 2). The
most significant aftershock was the
22 February 2011 M 6.3 Christchurch
earthquake which caused more than
180 deaths and major damage in
Christchurch. Another M 6.3 aftershock
occurred east of Christchurch on
13 June 2011; however, its impact on
the city was much less severe than the
February aftershock. This is likely due
to factors such as the epicentre being
further from the city than the February
earthquake, the faulting style not
directing the energy directly at the city,
and the June earthquake not generating
the extremely high vertical ground
accelerations that the February
earthquake did.
Figure 2 shows the number of
aftershocks per day located by GeoNet
in the Canterbury region since the
Darfield earthquake. The highest number
was more than 320 on the third day of the
aftershock sequence. Due to the high
number of large magnitude aftershocks
over the first two days, it was not
possible to locate many of the smaller
aftershocks. Therefore, the number of
located aftershocks during the first two
days is actually much lower than the true
number of aftershocks. Figure 3 shows
– GeoNet
of the best-recorded major earthquakes
anywhere in the world. Analysis of strongmotion accelerometer data and satellite
(geodetic) data shows that the Darfield
mainshock was a complex event with at
least three distinct fault ruptures which
occurred in rapid succession. Scientists
are finding that many major earthquakes
around the world may be quite complex
events like the Darfield earthquake and
consist of several distinct fault ruptures.
Figure 2: The number of aftershocks per day located by GeoNet since the 4 September 2010 M 7.1
Darfield earthquake. Note the increased number of aftershocks following the two M 6.3 events.
Figure 1: Map showing the locations of the three largest earthquakes in the Darfield sequence (stars) and
the aftershock sequence as of 27 September 2011. The Greendale Fault is marked by the thick red line, and
yellow dashed lines are inferred sub-surface fault ruptures.
the number of aftershocks located by
magnitude. More than 94% are in the
magnitude range M 2.0 – 3.9. Most
aftershocks with M < 2 will have been
too small to locate, which is why there
are so few in the M 1.0 – 1.9 range. It
is impossible to predict when the
aftershock sequence will end and there
will likely be an increased level of seismic
activity in the Canterbury region for
several years to come. However, over
time the aftershocks will get less
frequent, and the larger aftershocks
The vast amount of data collected from
the Darfield earthquake and its aftershock
sequence will allow New Zealand scientists
to be at the forefront of research into large
earthquakes. Understanding the geologic
processes that lead to major earthquakes
will improve our understanding of seismic
hazard. This will lead to improved building
codes and safer living conditions, which is
important in a seismically active country
like New Zealand.
will become fewer and spread further
apart in time.
Scientists at GNS Science have been
working diligently over the past year to
understand the details of the Darfield
earthquake and the aftershock sequence.
The Canterbury region is one of the
most densely instrumented regions in
New Zealand, with a large number
of seismometers, strong-motion
accelerometers and GPS sites located
throughout Christchurch and Canterbury.
As a result the Darfield earthquake is one
Many research projects are continuing on
the Darfield earthquake and aftershock
sequence. Scientists are currently
working on an in-depth analysis of the
complex interplay of stresses that
connect the Darfield earthquake with the
two largest aftershocks. The distribution
and timing of all the events in the
aftershock sequence will play an
important role in understanding the
details of the stress patterns. There is
also an intensive programme underway
to map as many faults as possible in
Christchurch using various geological
and geophysical techniques. Aftershock
forecasts showing the probability for
aftershocks with M ≥ 5 over the coming
month and coming year are constantly
being revised and the analysis posted on
the GeoNet website. Geodetic research is
being done to analyse the changes in the
long-term stress and strain pattern in the
Canterbury region and what this might
mean for any future large earthquakes.
Figure 3: Distribution in the number of aftershocks by magnitude. The vast majority of aftershocks fall in the
M 2.0 – 3.9 range.
Contact: John Ristau
Email: [email protected]
GeoNet – Below (left to right): Helicopter dropping off a load of
equipment; technicians concreting the vault; the team
hard at work.
OUT IN THE FIELD – BUILDING RTZ
In April this year, construction began on RTZ, a National Seismograph
Network site near the small town of Ruatahuna, about 100km southeast of
Rotorua. Despite a site having been planned for Ruatahuna for years, the
challenges posed by its remote location - surrounded by the forests of the
vast Te Uruwera National Park and other Department of Conservation
land - has meant it is the last planned addition to the network to be
permitted and built.
The new station at Ruatahuna was
chosen to complete the National
Seismograph Network coverage in the
area. This network is made up of 51
stations across New Zealand that provide
the ‘backbone’ of seismic monitoring
across the country. Unlike the
supplementary regional and strongmotion networks which transmit their data
using radio, cellphone and internet paths,
national network stations use satellite
communications (VSAT), which are
considered to be more reliable during
large earthquakes. They also use both
strong-motion and broadband
instruments, allowing them to accurately
record a wide range of earthquake
magnitudes. GeoNet aims for these
robust stations to be evenly distributed
throughout the country and the new
site at RTZ was strategically located
to complete this coverage.
Before a new station is installed a lot
of time is put into choosing a suitable
site, with quality and practicality being
the most important factors. The site must
be easily accessible for installation and
maintenance, and also have a means of
transmitting the data back to the GeoNet
Data Centre. The GeoNet Network
Development Team identify and refine
potential ‘ideal’ locations for the station
by considering geology, topography,
access and communications options.
Ideally, a good seismograph site will be
on solid rock, with little exposure to wind
and far from trees, rivers, roads, buildings
or machinery, as these all create ‘noise’
(shaking that is not due to seismicity)
that can mask the earthquake data being
recorded. A desirable site will have a high
signal to noise ratio, meaning earthquakes
show up clearly compared to the
background noise. After the desktop
planning identifies these locations, ‘test
sites’ are installed – temporary
seismograph stations that are left
recording for 3-4 weeks before being
dismantled and brought back to the Data
Centre. Their earthquake data are then
analysed and compared to decide which
location is most suitable for the
permanent station.
At Ruatahuna selecting a suitable site
was a challenging task. It is amongst
dense vegetation with the only clear land
down on the river plains or in a few of
the hills, which are potentially noisy
environments due to soft river sediments
and high winds, respectively. In addition
the options for transmitting data were
limited, the high hills surrounding the
town ruled out radio links without
installing at least one additional repeater,
no DSL internet existed and VSAT, which
requires mains power, was only an option
for sites close to the township where
there was power but the soft rock made
the data quality poor. The solution
eventuated through exhaustive site
testing and compromise. After testing six
sites, a location was chosen on a hilltop
east of the town with visible greywacke
exposures accessed by a track that takes
20 minutes by quad bike. To solve the
communications difficulty the site was
planned to include a solar powered VSAT,
only the second of its kind in GeoNet’s
networks with four 125W solar panels and
8 24V batteries providing power.
The last step was obtaining the
permission of the landowners to install
the facility, a complicated process which
took over six months. Finally however,
after extensive planning, testing, and
negotiating, the location and design of
the site was approved.
The site took the team of GeoNet
technicians just over one week to
complete, and is now up and running
as part of our nation-wide network.
For more details, photos and video
of the Ruatahuna site construction
visit the GeoNet Blog at http://geonetshakennotstirred.blogspot.com/
(Archive: April)
Contact: Lara Bland
Email: [email protected]
Below: The completed site.
Social Media
In 2010 GeoNet joined the ever-growing
social media platforms ‘Facebook’ and
‘Twitter’ and more recently a blog was
started on ‘Blogger’. All of these
services are available via computer and
mobile phone.
Some of the benefits of using social
media in conjunction with our website
include the fact it’s fast, easy to use and
extends the audience reach. Social media
also let GeoNet release facts, keep
people informed and alerted to problems
(such as instrument outages on the
website) and also let the public engage
with us and each other, which can be
important during large events.
– GeoNet
Blogging has also allowed the public
a look ‘behind the scenes’ at GeoNet,
with videos touring the offices and
photos documenting how technicians
build new sites out in the field. It also
has frequent ‘how to’ posts with
information on how to use various
features on the GeoNet website.
Although the GeoNet website is still the
main way to get information about all of
New Zealand’s geological hazards, with
over 13,000 people following Facebook
and over 9,000 on Twitter, social media
allow GeoNet to get information out
quickly to a wide audience.
Contact: Sara Page
Email: [email protected]
www.twitter.com/geonet
www.facebook.com (search GeoNet)
http://geonet-shakennotstirred.blogspot.com
GeoNet – Mitigating Eruption Risks - A look at Geothermal
Monitoring in New Zealand
Volcanologists use many techniques to monitor
active volcanoes – the primary ones are
seismology (earthquakes), geodesy (ground
deformation) and geochemistry (gas and water
chemistry). Volcanic surveillance is based on the
assumption that molten rock or magma beneath
a volcano will move closer to the surface before
any eruption can start. The movement of magma,
or changes associated with it moving, are
detectable using various methods; one of these
is monitoring geothermal systems.
Geothermal systems are composed of
the thermal energy stored in the hot rock
(magma) at depth, which is carried by
local ground water to the surface, and is
expressed as hot lakes, springs or pools,
streams, steaming ground, fumaroles and
mud pots. Changes in the amounts of
volcanic gas and water given off from
magma, or amount of magma in contact
with the ground water, can be reflected in
the chemistry of surface features, hence
the rationale behind monitoring
geothermal systems and features.
Recently the tour operators on
Mokoia Island noticed that the springs
feeding Hinemoa’s Pool were heating
up. They contacted GeoNet, as they
were concerned that the ‘volcano’ may
be waking up. The spring was sampled
and GeoNet was able to show that
there have been no changes in the
chemistry since the 1970s, and the
temperature has fluctuated from 42 to
54° C. This is just one example of the
benefits of maintaining a long-term
monitoring programme.
GeoNet volcanologists sample a selection
of the hottest and largest discharging
features in most of the geothermal
systems in the Taupo Volcanic Zones,
building up a database of the chemistry,
temperatures, flows and water levels. This
historic record is then used to assess
changes and look for indications of the
volcano system changing, or confirm it
has not changed.
Contact: Brad Scott, Karen Britten
Email: [email protected],
[email protected]
– GeoNet
Images: GeoNet
technicians taking
samples from
Whakarewarewa
Village, Rotorua
GeoNet – Taranaki Seismic Upgrade Completed
VITAL PEOPLE IN THE GEONET PROJECT
In 2010 GeoNet
completed a major
upgrade to its seismic
monitoring programme
in Taranaki. The
upgraded network
now covers a larger
area with more
seismographs and
uses state of the art
technology.
GeoNet’s interest in Taranaki is threefold:
monitoring Mt Taranaki volcano for signs
of its next eruption; collecting information
to understand the earthquakes and
structure of the region; and providing
important data for earthquake location
in western New Zealand.
Planning For a Volcanic
Crisis – short course
When: 16-18 November 2011
Where: Mecure Hotel, Auckland
Contact: [email protected]
Emergency Management
Summer Institute 2012
When: 12-16 March 2012
Where: Massey University, Wellington
Contact: [email protected]
Image (Above): Dairy farming below Mt Taranaki. (Below): The completeted Taranaki network
Mt Taranaki has not erupted since 1854,
but its next eruption could have a major
economic effect on Taranaki and further
afield. Earthquake activity is likely to be
one of the main early warning signs of an
eruption, so strong and reliable seismic
monitoring is essential.
10 – GeoNet
Anya Seward
Hien Tran
GeoNet Data Centre Technician
GeoNet Analyst Programmer
Anya joined GNS Science in May 2010
as a Geophysics Survey Coordinator
in the Natural Resources Department for
the SAHKE (Seismic Array – HiKurangi
Experiment) project. After the successful
completion of the project, Anya has
joined the GeoNet team as a Data
Technician for a 12 month contract.
Her main responsibilities are to prepare,
analyse and compile geophysical data,
assist scientists in their research projects,
and assist with the outreach objectives
of the GeoNet project.
Hien joined the team at GeoNet at a
very interesting time - when the second
major earthquake struck the city of
Christchurch in February. In response
to the earthquake, he quickly took on
his role as an Analyst Programmer for
the GeoNet systems development team,
implementing the ‘View Felt Reports’
in Google maps feature for the GeoNet
website. Since then he has worked on
various other projects including:
development of the GeoNet website
visualisation software for volcanic data,
development of the new Felt Administration
application, and investigation of the latest
mobile technologies. Currently Hien is
developing software that will replace the
existing felt earthquake reporting
application on the GeoNet website.
Before joining GNS Science, Anya
completed her PhD in seismology at
Victoria University of Wellington, on
upper mantle Pn wave phases in the
Central Volcanic Region of New
Zealand. Since the completion of her
PhD she has been involved with various
projects with Victoria University and
GNS Science aimed at understanding
the seismic structure beneath
continental New Zealand.
The accumulated effects of past eruptions
have left the crust beneath Mt Taranaki
slightly warmer than its surroundings,
which means earthquakes there are
shallower than other parts of Taranaki.
The upgraded network will give improved
earthquake locations which in turn will
help better understand how Mt Taranaki
affects earthquakes in the region.
The network is made up of an inner
group of sites focused on Mt Taranaki
and an outer group to add the regional
capability. Site selection in Taranaki,
however, was not easy - intensive dairy
farming meant that many potential sites
were too noisy to be used. Finding sites
on the exposed upper slopes of Mt
Taranaki was particularly difficult, and
Coming up...
in one case a special borehole had to
be drilled to reduce noise to acceptable
levels. Despite these difficulties, the
network has grown from six to nine
sites and importantly is now more
reliable and effective.
We don’t know when Mt Taranaki
will next erupt, but with the help
of an upgraded network we will all
be better prepared.
Contact: Steve Sherburn
Email: [email protected]
Anya has been keen to get involved
with the GeoNet project since first being
introduced to it in 2003. She believes that
the work and objectives of GeoNet are
very important for not only understanding
the natural hazards that surround New
Zealanders daily, but also the need to
keep the public informed of the risks and
the hazards of the regions they live in.
Email: [email protected]
6th Australasian Natural
Hazards Management
Conference 2012
When: 21–22 August 2012
Where: University of Canterbury,
Christchurch
Contact: ahmc@hazards-education
Website: www.hazardseducation.
org/conference
In 2010 Hien was one of the first few
graduates to have completed the
Bachelor of Engineering with a major
in Software Engineering with Honours
at Victoria University. While completing
his degree, Hien worked as a tutor for
various Software Engineering courses,
and contracted as a Java Developer
for iPredict.
Hien enjoys the various challenges that
arise from his role as GeoNet’s Analyst
Programmer and finds it very rewarding
and satisfying knowing that his work
contributes to New Zealand society.
Email: [email protected]
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 2011
In response to the February 22 Christchurch
earthquake, 4 temporary strong-motion
accelerometers on the Port Hills and six temporary
short-period seismographs were installed to
improve the network geometry in the region.
Following the June 13 magnitude 6.3 earthquake,
two extra cGPS units were installed above Sumner
and an existing one was moved.
July 2011
INZ
National Seismic Network site at Inchbonnie
on the West Coast.
RAKW
cGPS sites were made operational at Raukawa
in Hawke’s Bay, Manuhara Road, near Pongaroa
and at Parikino, north-east of Whanganui.
MNHR
PKNO
DUWZ
The Wellington Regional Seismic Network
seismograph at D’Urville Island was upgraded.
FAIS
SEVS
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.
LRRS
August 2011
EPAZ
Borehole seismic site was completed at Eden Park,
Auckland, at a depth of 383m.
GKBS
Strong-motion sites at Kaiti Beach in Gisborne, Wainuiomata Hill, Wellington.
Waikakaho Road in Blenheim,
Halswell School, Akaroa School
and Methven North.
WANS
BWRS
EYRS
Strong-motion site at the Eyrewell Observatory - this
is the site of the national geomagnetic observatory.
AKSS
HSES
One Etna at Hanmer Springs Emergency Centre
and three CUSP-3 strong-motion instruments at
Waikari, Dunsandel School and Mayfield School
were upgraded.
DSLC
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
Strong-motion sites were installed in Lower Hutt
and Wellington. At Fairfield, Seaview, Victoria
University Law School and Randwick School.
March 2011
MAYC
GeoNet website: www.geonet.org.nz
Email: [email protected]
Address: GNS Science, PO Box 30-368,
Lower Hutt 5040, New Zealand
Editor: Sara Page
VUWS
WAKC
Contact details
HALS
Main funding agency:
MTHS
KPOC
TPLC
Canterbury sites received upgrades to more
sensitive instruments: Kaiapoi North School,
Templeton School and Westerfield.
EPAZ
WSFC
KMRZ
MUGZ
Regional Seismic Network sites at Kaimai, near
Murupara and one near Ohakea.
TURI
cGPS site at Te Uri, near Dannevirke.
KMRZ WHRZ
RAUM
RUGZ
OHWZ
MUGZ
April 2011
TGRI
cGPS site near the southern end of Lake Taupo,
at Rihia Road
CHTI
The last of the 36 PositioNZ continuous GPS sites
was upgraded from a NetRS to a NetR9 receiver.
This was the Chatham Island North site.
MKBS
TAIS
LIRS
FAIS
PTOS
SEVS
May 2011
NBSS
VUWS
RTZ
National Network site established near Ruatahuna.
PVCZ
LRRS
RUGZ
Combined seismic and continuous GPS site in the
Raukumara Range, about 35 km east of Opotiki.
UHSS
WANS
MKBS
LIRS
Two continuously recording strong-motion
accelerographs were installed, one at Makara
Bunker and another at Lower Hutt IRL.
June 2011
WHRZ
Seismic site completed at Whale Island in the
Bay of Plenty near Whakatane.
PTOS
Five continuous strong-motion recorders were
installed around the Hutt Valley, Petone Overbridge,
St. Bernadette’s School, Petone Victoria Street,
Upper Hutt Primary School and Taita Central School.
NBSS
PVCZ
GKBS
PKNO
OHWZ
RAKW
TURI
MNHR
DUWZ
BWRS
ISSN 1176-0567 (Print) ISSN 1178-4201 (Online)
RAUM
RTZ
TGRI
INZ
HSES
WAKC
TPLC EYRS KPOC
HALS
DSLC
MTHS
AKSS
MAYC
WSFC
UHSS
TAIS
12 – GeoNet
Lead organisation in the GeoNet project