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GeoNet News Issue 20

The latest issue of our newsletter "GeoNet News" is released today.

GeoNet News 20.pdf (5.97Mb)

Featuring: Social media and disaster information, New Zealand's revised Volcanic Alert Level system, Hillary Ridge rock avalanche, Dart River / Te Horo Landslide, Monitoring remote crater lakes from space.

 

Previous issues can be found on the archives page.

GeoNet has recently expanded its Auckland data centre presence by obtaining additional space at a major telecommunications hub in Kingston Street, Auckland. Dave Campbell and Robert Pearce finished up the last of the hardware installation earlier this week.

This will allow the project to obtain higher-quality access to third party networks, both to access data from our instruments around New Zealand and to better utilise offshore cloud services. It also gives us increased network bandwidth diversity, thereby increasing the resiliency of the project.

Since the beginning of GeoNet in 2001, our backup site for data centre activities and networking has been GNS Science's Wairakei office. Moving much of the core communications infrastructure to Auckland while lowering the footprint at Wairakei also allows quicker and more reliable access to our equipment should an unexpected issue arise, especially as same-day support from our suppliers has been unobtainable at Wairakei.

What does this mean for you? You shouldn't notice a thing: that means it's working!

GeoNet News Issue 19

The latest issue of our newsletter "GeoNet News" is released today.

GeoNet News 19.pdf (1.05Mb) 

Featuring: Collecting Data from Mt. Ruapehu, Cook Strait Quakes: An Update, Eketahuna Earthquake, Volcano Update, Recent Additions to the Website.

 

Previous issues can be found on the archives page.

We've changed our 'felt quakes' list on the website so you can search out the big quakes in your region.

Since the start of the Cook Strait earthquake sequence, the most common feedback we've had about the website was that a list of 30 felt quakes was not enough. During New Zealand's normal background level of earthquakes a list of 30 felt quakes for a region will span days to weeks. But when there are a flurry of aftershocks like we've been having around Seddon and the Cook Strait, the list of 30 felt quakes may only cover a few hours.

We understand that if you're in bed or out and about and you feel an earthquake you still want to be able to find it on our website, and you'd like to easily revisit the significant quakes.

Check out the changes we've made to the felt lists for the regions around the country, there are examples in the figures on the right. You can now select the minimum intensity of the earthquake that you want to look at, so weeding out the smaller or more distant quakes. The list includes up to 30 quakes in your chosen category, going back one year.

One interesting feature about the pages is the list of quakes you will see. Not only will it show quakes in your own region but it will have earthquakes that could have been felt somewhere in your region but occurred in a different region. An example is in the screenshot to the right of the current list of felt earthquakes in Auckland - the large M6.5 Seddon quake is in the list as it's region intensity for Auckland and Northland is weak.

A couple of weeks ago we also added searchable maps to the website, again letting you turn off and on different intensity earthquakes.

GeoNet News Issue 18
The latest issue of our newsletter "GeoNet News" is released today.

GeoNet News 18.pdf (1.12Mb)

Featuring: Cook Strait Quakes, Our Volcanoes: An Update, Canterbury Seismic Network, Waimangu Crater Lakes and Our Earliest Earthquake Record Keeper.

 

Previous issues can be found on the archives page

For those of you using the geonet.org.nz website this afternoon, you may have noticed a few issues - we are really sorry about this.

The GeoNet website experiened disruptions for around an hour because the provider that hosts our servers went down. We were able to run our backup website so all the earthquake information was kept up-to-date, but it did break some pages and links. We also couldn't record any felt earthquake reports, send out earthquake tweets or send push notifications on the mobile app. 

Again, we are sorry for this disruption and hope it doesn't happen again, but rest assured if it does we are still able to keep our eyes on the country's earthquakes and volcanoes.

 

Website Update

As we continue to bring you faster information about New Zealand's geological hazards we are also continually working on our website.

We have listened to feedback from our valued users and have now added Volcanic Alert Levels to the homepage, with a link to Volcanic Alert Bulletins. Now when you visit Geonet.org.nz you will see the latest earthquake activity, as well as the current status of our volcanoes.

We have also added a new tab and link on the Volcanoes page which take you to the Volcanic Alert Bulletins, so during a volcanic event people can easily find the latest information.

We will continue to work on ways to better show you our valuable data via our website, on both mobile and computer devices, and look forward to bringing out a faster more interesting way for people to complete 'felt it' reports on their mobiles via our free app 'GeoNet Quake' later in the year.

The latest issue of our newsletter "GeoNet News" is released today.

GeoNet News - Issue 17, Feb 2013 (971 kB)

This issue is all about out Volcanoes - Including the recently active Tongariro and White Island, the Monowai Submarine Volcano, Volcano Gas flights - what are we measuring? And the faces behind
the science.

The New Zealand Open Source Awards 2012 were made on November 7. They recognise and promote the contributions of New Zealanders to free and open source projects and free and open source philosophy. We are proud to say we picked up 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. The primary aim of GeoNet Rapid is to make earthquake locations available via the internet faster - specifically within five minutes or less of an earthquake occurring. A key component of GeoNet Rapid has been to make earthquake information available across a variety of platforms including smart phone applications for Android, iPhone, and iPad.

  • 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. The free access to information has proved its value many times over during the period since the Christchurch earthquakes. It has allowed the creation of many data visualisation websites and projects as well as numerous scientific publications, special journal editions and presentations that make use of data from GeoNet.

In both cases the foundations for the initiatives were laid many years ago by people with foresight and dreams; we would like to acknowledge all who have played their part along the way to where we are today.

On September 5 GeoNet Rapid became our official earthquake location system. Since that time we've been busy with your feedback and initiatives of our own.

Earthquake Notifications

Previously you waited until the Duty Officer had manually checked the earthquake before you received any details. With our automated system you can get details much, much sooner. Sometimes a bit too soon; we've since modified our alerts to wait until we've received sufficient data to be more confident in our notifications. Remember it's still preliminary at that stage, and it's best for you to check back with the website to see the latest and best information.

Earthquakes Prior to 2012

Our old website only featured web pages for earthquakes that were felt or likely to have been felt. Now every earthquake in the New Zealand catalogue has its own page.

How do I find the page? If you know the earthquake's Public Id (also sometimes called CUSP Id or Reference Number), then type the web address http://www.geonet.org.nz/quakes/{Public Id} into your browser, for example:

Felt Report Maps

Yes, each of these pages will also show all the felt reports in our database. Check out some of the Historical Quakes - go to the GeoNet Summary link.

Catalogue Searches

The Simple Queries facility is used by a lot of you for getting a list of earthquakes from the New Zealand catalogue. At the moment it only returns earthquakes up until our go-live date of September 5, 2012. You can now also use our Web Feature Service to query both old and new earthquakes and return them in a variety of formats.

Waveform Data

For researchers, we've added the new Public Ids into the waveform retrieval client; at this stage P and S picks are not available for these but they're in the pipeline.

 

The ANZIAs 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 August GeoNet was announced as a finalist in the Information category - Initiatives that bring information, knowledge and materials online.  And Last night in Canberra at the awards ceremony GeoNet won!

From ANZIA:
"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 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 GeoNet team are very proud of GeoNet Rapid and it's great to be recognised after all of our hard work.

We try to get you the best earthquake information possible as quickly as we can. On 20 September 2012 we got it wrong, locating two earthquakes near Auckland when really they were near Christchurch. Here's how we've improved things:

We use a system that locates earthquakes automatically so that we can get earthquake information to you as quickly as possible without having to wait for a person to manually locate the earthquake. In general, automatic earthquake locations are likely to be better when more data is available. We try to use the automatic earthquake location system to do two things:

• Make earthquake locations very quickly – as soon as we have enough data available to make an initial location.

• Locate all earthquakes – even the really small ones, where we never have very much data available.

There are trade-offs here between speed, accuracy, and locating all the small events. The longer we make the system wait for more data, the longer it takes to tell you about an earthquake. If we make the system always wait until it has a lot of data, it will never locate the small earthquakes. We try to tune the system to be good at both but on 20 September it went wrong. The location for these two earthquakes 2012p71054  and 2012p710605 both had problems. The location system put them near Auckland and Opunake with the wrong magnitudes before correcting itself very quickly. Unfortunately, by the time it corrected itself, we had already let people know there were large earthquakes nowhere near where they really occurred. This made a lot of people nervous and that is the last thing we want to do!

We will continue to tune the earthquake location system to improve it. We're also changing the way we send you information via Twitter. We want to get you information as quickly as possible but also to make sure it's accurate.

Here's how it will happen. Once the location system has received enough data to make a location that is likely to be good, or the Duty Officer has reviewed the location, we will send the details to @geonet, as well as @geonet_above4 and @geonet_above5 depending on the magnitude. There will only be one tweet about each quake, so go to the web site to see any updates. The tweet will be, for example:

Quake 85 km east of Ruatoria approx. M3.5, depth 20km, intensity moderate http://geonet.org.nz/quakes/2011a868660 Fri Nov 18 2011 10:42 PM (NZDT)

We will be dropping the feed to @geonet_all, as we don't want poor quality information upsetting folk again.

We hope these changes improve the balance of accuracy and speed of earthquake information via Twitter. Don't forget you can get rapid earthquake information from our smart phone apps for Android and iPhone/iPad!

Felt? Really?

GeoNet is now bringing every quake it can locate to the website. No longer do you have to wait for a seismologist to decide whether an earthquake was worthy of inclusion. But as you know, the vast majority of earthquakes remain unfelt and therefore really only of scientific interest. It makes sense then to present a refined list of earthquakes that were likely to have been felt.

One way to be really sure that an earthquake was felt is to wait for felt reports to come in. But that's all a bit circular, because ideally if you've felt an earthquake, it is right there in front of you when you first hit www.geonet.org.nz. So what does the very first person do?

As of today we've refined the logic that decides the likely candidates - it's all based on the shaking intensity at the epicentre (that's at the surface of the earth), and the distance from the nearest significant population centre to the hypocentre (that's the place underground where the earthquake began - it can be very deep). If you check out the regional lists now, you'll see they feature more appropriate earthquakes for your favorite part of New Zealand.

Last month's new sites, volcano surveillance results, earthquake summaries, data products and other news from GeoNet, New Zealand's geological hazard monitoring system.

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This is the last monthly round-up in this format. In future we will be updating more regularly as news comes to hand.

Additions and upgrades to the geophysical monitoring networks

  • Two SAGENZ (Southern Alps Geodetic Experiment New Zealand) continuous GPS sites near Mount Cook National Park, Mount Hodgkinson (HORN) and Cox's Downs (BNET), were upgraded and data communications installed.
  • A strong-motion site at Inglewood High School (INHS) was upgraded and re-located.

Earthquakes summary

  • The most reported felt earthquake of the month occurred on Friday, August 31, magnitude 5.2, 30 km south-west of Haast at a depth of 3 km; we have received 954 felt earthquake reports (across the official and beta sites) to date.
  • The preliminary locations of July and August's earthquakes located by our seismologists are shown below. Not all events for these months have been fully analysed as yet and these maps will be updated when the month is finalised.

 

 

Volcano monitoring update and field trips

Summary

  • August was a very busy month for the volcano monitoring team as eruptive activity occurred at four different volcanoes during August.
  • Following unrest in July a moderate explosive eruption occurred at the Te Maari craters on Tongariro volcano on 6 August.
  • Following unrest in late July explosions and ash emissions restarted at White Island in early August. This is the first eruptive activity at White Island since 2001.
  • Further submarine activity was recorded at Monowai volcano. This is a frequently active submarine volcano north of Raoul Island.
  • Large pumice rafts were identified near the Kermadec Islands in early August. Analysis of remote sensing data has shown that thess came from a submarine eruption at Havre submarine volcano on around July 17/18.

Tongariro response

  •  An eruption occurred at 23:52 on 6 August and led to a coordinated response between civil defence agencies and scientists.
  • Data collected by GeoNet has been crucial to understanding the eruption.
  • Two of the GeoNet instruments were destroyed by the eruption, but data was being transmitted from the seismic sensor until just after the start of the eruption.
  • After the eruption, GeoNet has continued to monitor the volcano using permanent seismic sensors, airborne gas geochemistry and sampling of fumaroles across Tongariro.
  • A wide range of scientists from universities and crown research institutes across New Zealand have contributed to data collection and interpretation.

White Island response

  • Eruptive activity at White Island started in early August and included an explosive eruption that was captured on the webcam. A new ash cone was built within the crater lake and minor emissions continued intermittently through the month.
  • Two visits were made to observe the activity, sample gases and undertake a levelling survey. Gas flights were made to measure output of different gases in the volcanic plume.

Wednesday August 1 - Gas flight over White Island

White Island was flown under very good conditions, with a 13 knot north-easterly wind. The lake level was higher with vigorous ebullition from the centre of the lake.

SO2 flux was slightly higher and CO2 flux was slightly lower than the last survey. But there was an important increase in H2S flux with 18 t/day measured this trip.

White Island Gas

Method

01/08/2012
(T/day)

29/06/2012
(T/day)

SO2 emission (Cospec)

421

NA*

SO2 emission (Flyspec)

466

407

CO2 emission (Contouring)

1,727

1,850

H2S emission (Contouring)

18.2

8.3

SO2 emission (Contouring)

NA

462

* NA - not available due to instrument problem

Thursday August 9 – Gas flight over Tongariro

Conditions were good, with a 8.3 m/s southerly wind, which was ideal for measuring the Tongariro plume.

Tongariro Gas

Method

(T/day)

SO2 emission (Cospec)

2,091

CO2 emission (Contouring)

3,906

H2S emission (Contouring)

364

Friday August 10 – Gas flight over White Island

White Island was flown under very good conditions with a low wind speed 7 knots from the south-west. We couldn't see the crater and no ash was seen during the flight.

SO2, CO2 and H2S fluxes decreased since the previous survey on August 1.

White Island Gas

Method

10/08/2012
(T/day)

01/08/2012
(T/day)

SO2 emission (Cospec)

194

421

SO2 emission (Flyspec)

225

466

CO2 emission (Contouring)

789

1,727

H2S emission (Contouring)

3.5

18.2

SO2 emission (Contouring)

NA*

NA

* NA - not available due to instrument problem

Friday August 17 – Gas flight over White Island

Flying conditions were very good with a 15 knot wind from the south-west quarter.

White Island Gas

Method

17/08/2012
(T/day)

10/08/2012
(T/day)

SO2 emission (Cospec)

425

194

SO2 emission (Flyspec)

NA1*

225

CO2 emission (Contouring)

1,585

789

H2S emission (Contouring)

5.8

3.5

SO2 emission (Contouring)

273

NA2*

* NA1 – instrument absent for servicing
*
NA2 - not available due to instrument problem

Wednesday August 22 – Gas flight over Tongariro

Wind was 6.9 knots from the south-west. A strong aerosol plume was observed.

The SO2 flux had dropped to 383 T/day.

Friday August 24 - Gas flight over Ruapehu

Ruapehu gas flux was successfully measured under good conditions with a 5.8 knot wind from the east-north-east.

Ruapehu Gas

Method

24/08/2012
(T/day)

02/07/2012
(T/day)

SO2 emission (Cospec)24NA**
SO2 emission (Flyspec)ND*ND
CO2 emission (Contouring)790630
H2S emission (Contouring)0.20.4
SO2 emission (Contouring)29.624.5

* ND - not detected
** NA - due to equipment damage

Ngauruhoe was flown but the plume from Tongariro swept over the volcano making measurements from Ngauruhoe impossible.

Friday August 24 - Ruapehu Crater Lake visit

Ruapehu Crater Lake was sampled in nice sunny conditions. The lake was a uniform turquoise blue colour, with some yellow slick and no clear signs of upwelling. Central vent and North vent were sampled both for water and gas. Water temperatures were 22.5 °C for North Vent and 20.7 °C for Central Vent. The lake was right on the overflow level and was overflowing a bit.

Wednesday August 29 – Gas flight over Tongariro

A flight was carried out under reasonable conditions. The wind was at an awkward angle from the east-south-east, which made it hard to distinguish gas coming from Ketetahi. The plume rose upwards, then started to fly when it reached the volcano summit height. It appeared to split into two, the main plume coming out to the west-north-west and a small part of it hugging the volcano and drifting against its flanks over Ketetahi and towards the Mangetepopo valley. All the gases appear to be on the decrease.

Tongariro Gas

Method

29/08/2012
(T/day)

22/08/2012
(T/day)

09/08/2012
(T/day)

SO2 emission (Cospec)1513832,091
CO2 emission (Contouring)417NA*3,906
H2S emission (Contouring)30NA364
SO2 emission (Contouring)329NANA

* NA - not available

Reported landslides from media sources

Friday August 3

  • Titirangi Drive, Kaiti (near Gisborne) was affected by slips and barely passable.
  • Tauwhareparae Road (inland from Tolaga Bay) was reduced to one lane by slips.
  • Tiniroto Road, Waerengaokuri, was reduced to one lane by landslips near Bushy Knoll Rd turnoff.

Saturday August 4

  • One lane of SH 2, the Rimutaka Hill, was blocked by a slip 3 km west of Featherston near Twin Bridges.

Monday August 6

  • Minor rock falls were generated on Tongariro by earthquakes generated by the eruption just before midnight, and a debris flow has been observed in a stream near the eruption site.

Wednesday August 8

  • SH1 between Christchurch and Blenheim was completely blocked by a slip about 20 km south of Ward. The highway was partially re-opened by morning on August 9.

Thursday August 9

  • As a result of heavy rain in Marlborough there were landslides in the Awatere Valley that partially blocked the road, Ure Road at Ward was passable only by 4WD vehicles due to slips and Kenepuru Road was also affected by slips near Kenepuru Head and was also only passable by 4WD vehicles. Rockfalls and flooding of Northbank Road, Okaramio  was also reported. Camerons Road at Seddon was closed to heavy vehicles by slips. In the North Island, Parikanapa Road, Tiniroto, was affected by slips.

Friday August 10

  • Khyber Road in Seatoun, Wellington remained closed for landslip clearances since 22 June when slips affected Kakariki Road and adjacent Khyber Road.
  • Further rain in Marlborough affected Medway Road at Seddon and closed the Port Underwood Road between Whatamango Bay and Oyster Bay.

Sunday August 12

  • Heavy rain in the far north caused slips at Matauri Bay Road (SH 10) near Kaeo.
  • The Lower Kaimai road, SH 29 near Tauranga was closed due to the risk of rockfalls from the Ruahihi Bluffs as a result of heavy rain.

Monday August 13

  • Rockfalls were reported on the Rimutaka Hill, SH 2 between Featherston and Upper Hutt.
  • A mud slide in Hawkhurst Street, Lyttelton, severely damaged a house. Also cracks in the top of the cliff at Lucas Lane in Hillsborough necessitated the evacuation of four houses while the situation was assessed.
  • Landslips at Kaiti Beach Road near Gisborne, was reduced to one lane by slips.
  • SH 30 at Te Ruato Bay (south shore of Lake Rotoiti) was affected by rock falls and reduced to a single lane controlled by lights.

Tuesday August 14

  • Four cliff-top houses in Rewarewa Place, Matua (near Tauranga) were threatened by two failures of the cliff at the rear of the properties, which came within 10 to 15 m of the houses.

Wednesday August 15

  • A large rockfall occurred from the face of Lovers Leap above the Rees Valley near Glenorchy. It dropped from about 600 m above Cockburns Bush, and a preliminary estimate of volume is in the order of several thousands of cubic metres.

Thursday August 16

  • Woodburn Road at Herbert, south of Oamaru, was closed by landslips, and another slip closed Fuchsia Creek Road, Five Forks, west of Oamaru.
  • Te Puna Station Road, at Te Puna, near Tauranga was closed by landslips.

Friday August 17

  • Awhitu Road (south of the Manukau Harbour entrance) was blocked by a landslide.

Monday August 20

  • Stag and Spey Roads, Conway Hills in North Canterbury were briefly reduced to one lane by landslips.

Tuesday August 21

  • A small slip on River Road, Tauranga, came down onto a public reserve from private land, and another, earlier slip at Tauhara Park was reactivated by recent rain.

Thursday August 23  

  • Taupo Bay Road, east of Mangonui in the Far North was affected by slips.

Friday August 31

  • Coast Road at Pongoroa was reduced to one lane by a landslip

This morning two quakes reports sparked alarm and interest - what's going on?

The great thing about our new rapid system SeisComP3 is that initial quake information is out within a few minutes of an event.  This tricky thing is that as more data becomes available, the size, location and depth of the event can change.

Most of the time the changes are small but occasionally the system makes some poor early estimates, and this can lead to large changes in location and magnitude!

When you get a Preliminary Quake notification, look at the Quake History and check the Quality – ‘Caution’ means it only has a few observations and treat with caution. ‘Good’ and ‘Best’ are the ones to pay attention to.

Check out the two events:

We're trying to balance getting quick notifications out rather than wait minutes before letting you know. This morning it has led to two earthquakes changing their locations and magnitudes radically - most particularly their magnitudes end up reduced to less heart-stopping levels. Today's earthquakes will help us to refine the notifications we send out, and we apologise for any alarm they've caused.


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

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