The Puysegur Trench Quakes of 30-9-2007 – Part 3

Problems and Solutions

Two large earthquakes in the Puysegur Trench on the evening of Sunday 30th September 2007 required a number of New Zealand government agencies to carry out their responsibilities for assessing, reporting and managing the risk to life and property. These agencies are also responsible for developing and deploying the technology that allows them to fulfill their tasks.

Following the confusion over whether a tsunami wave was headed for New Zealand after the strong earthquake near Tonga on the 4th of May 2006, the Ministry of Civil Defence and Emergency Management (MCDEM) was strongly criticised for failing to alert some local authorities and not communicating its assessment of the tsunami risk to the public.

With overseas television broadcasters stating that a tsunami had been generated, some residents in Gisborne took the initiative to move to higher ground. The Ministry had decided that a tsunami threat did not exist, but neglected to issue a statement to this effect. The absence of a denial of risk from the authority charged with making such decisions meant that the public had to make up its own mind on the matter.

The Puysegur Trench quakes of September 30th were the first opportunity for MCDEM to show how it had improved its ability to manage a tsunami event, and communicate with the public. The relatively close location of the epicentres to populated coastline made the challenge greater, as the arrival time of a wave would be much shorter than that which applied during the event near Tonga in 2006.

Management of Tsunami Events:
GNS Science, the National Institute for Water and Atmospheric Research (NIWA) and MCDEM are the three organisations who have a role in assessing tsunami risk to New Zealand. GNS Science provides the seismic expertise and data, NIWA provides knowledge of New Zealand’s maritime environment, and MCDEM is responsible for alerting government agencies and the public to any risk, as well as managing any civil emergency that results. GNS Science is also the lead organisation for the GeoNet project which makes information on earthquake events available to the public.

The two MCDEM media releases show that a panel of tsunami experts was convened to assess and monitor the threat of a tsunami arising from the magnitude 7.3 earthquake on September 30th. However, the findings of the panel were only made available in the second release, drawn up at 9:45 p.m., by which time any tsunami wave would have passed along most of New Zealand’s coastline.

Both releases, which were only made available to the public the day after the earthquakes, lack immediacy and clarity and, if they are the only two releases passed to the media about the event, are inconsistent. The second release refers to the withdrawal of a tsunami advisory for Southland and Otago, but the declaration of this advisory is not mentioned in the first release – so how was this important piece of information communicated to the public?

The first release uses tentative language when it states “…there is nothing yet to suggest that a tsunami of any size has been generated.” The uncertainty is accentuated in the second-last sentence where it actually mis-quotes the PTWC Bulletin by stating, “The Pacific Tsunami Warning Centre (PTWC) in Hawaii has stated that there is no risk of a Pacific-wide tsunami but a small local tsunami could in theory be generated.” With regard to the local tsunami risk, the PTWC bulletin of 6:38 p.m. actually points out, “However – earthquakes of this size sometimes generate local tsunamis that can be destructive along coasts located within a hundred kilometres of the earthquake epicentre. Authorities in the region of the epicentre should be aware of this possibility and take appropriate action.” Any judgement call of a “small tsunami” must have been made either by the ministry or by the tsunami expert panel.

For some reason, MCDEM prefers to use media releases to communicate its important instructions. To most people a media release = “spin” and the inclusion of quotes from the Director re-inforces the sense that the content is just opinion.

A better solution would be for MCDEM to follow the PTWC model by issuing numbered bulletins which use direct, factual language. The Ministry’s role is to advise and direct, and this it should do via informative and instructional bulletins built using standardised phrases. And, unlike the present media releases, the bulletins should be made available to the public via its own website. There are several packages available that would allow this to be done by staff with minimal training. In fact, one of the password-protectable blogging packages would allow this to be implemented almost immediately.

The bulletins should contain information on the event, consultations made, actions taken and advice to the public. With a little preparation, a library of standard phrases could be built up to be used in a cut-and-paste fashion to assemble bulletin templates which would simply need the variables relating to the specific incident to be added.

An immediate benefit would be showing the public that MCDEM was either actively managing a developing situation or had determined that there was no risk to the public. The long periods of silence currently give the public no idea as to whether officials are aware of a developing situation.

The tsunami expert panel:
In the first media release from MCDEM, written 70 minutes after the first earthquake, it was stated: “The GNS Science convened tsunami expert panel and NIWA scientists are monitoring and assessing information about the earthquake and sea level movements.” This implies that the panel had taken 70 minutes to convene and, if that was the case, is highly alarming.

Within 30 minutes of the earthquake, the panel should have convened via an audio conference and made a preliminary judgement of the risk of a damaging tsunami having been caused by the earthquake. Initial discussion material should have included the PTWC bulletin, knowledge of the size and location of the quake, a rough calculation of transit time for a possible wave, and any knowledge of past tsunami events. It is also possible that data from the long-period seismic sensors installed by GeoNet to detect tsunami-generating earthquakes could have been consulted at this time.

This first conference should have formed an initial view of the likelihood of a tsunami being generated by the quake, allowing MCDEM to alert the nearest local bodies, if necessary, and issue an initial bulletin. The panel could then disperse to carry out further research, reconvening half an hour later to form an updated opinion.

Reporting of the earthquake:
Part of GNS Science’s mission statement says, “Specifically, we are the national expert on geological hazards and risk, and their economic, social, and environmental impacts.” To achieve this aim, the crown research institute employs a number of highly respected scientists, and is active in all aspects of geological science from field-work and research, to theoretical modelling, observation and analysis of events.

GNS is the lead organisation in the GeoNet project, a joint effort with disaster insurer EQC and the Foundation for Research Science and Technology. GeoNet is a highly innovative project to update New Zealand’s seismic monitoring network and make the information freely available via its website and databases. The project has been both successful and popular, and the GeoNet website is well-known to Internet users here in New Zealand and overseas.

Since inauguration in 2001, the content and sophistication of the GeoNet website has continually improved, making use of locally-developed automation tools. Automated assessment of significant on-shore earthquake events allows seismologists to post information about the quake on the GeoNet website within half-an-hour on most occasions.

The reporting of significant off-shore earthquakes within New Zealand’s economic zone, has declined in recent years, however. During the 1990s, Victoria Univerity of Wellington’s Resource School of Earth Science pioneered the publishing of New Zealand earthquake reports on the Internet. Coverage extended as far north as the Kermadecs and as far south as the Auckland Islands for significant events. The Institute of Geological and Nuclear Sciences took over the site, and rolled it into the GeoNet project in 2001. One of the consequences of this seems to have been a decline in the reporting of more distant events.

New Zealand’s long, narrow shape makes it more difficult to analyse these off-shore events, but not impossible. Presumably, it takes more human intervention to determine the chracteristics of these quakes, and this may explain why they rarely appear on the automation-driven GeoNet website. The US Geological Survey provided good alternative coverage of the New Zealand area for offshore and deep onshore events, but this too declined early in 2006.

In some respects, GeoNet was the victim of its own success on September 30th, when many New Zealanders visited the website expecting to find information on the magnitude 7.3 earthquake. When nothing was posted for more than 2 hours, there was some confusion, as the seismograph drums clearly showed that a large event had occurred.

This was a serious oversight by GeoNet, which seems to have realised its lapse. A report of the second large quake was posted to the website within about half an hour. The GeoNet website contains a lot of background material, but I have been unable to find a publishing policy which sets the parameters for what is and isn’t published on the site.

Who is responsible for reporting tsunami waves in New Zealand waters?
This is a relevant question in an age when people want up-to-date information, and will use radio, television and the Internet to get it.

GNS Science has taken steps to detect the type of earthquakes likely to generate tsunami waves, through the installation of long-period seismic sensors.. However, this only indicates that a wave might have been generated. Detection of an actual wave requires the deployment of oceanic wave gauges which are actively monitored.

A look through the website of the National Institute of Water and Atmospheric Research shows that NIWA clearly sees oceanic monitoring as a logical extension of the coastal gauges that it already operates. It offers consultancy services in the field, including tsunami events, but there are no clear plans to deploy monitored oceanic wave gauges on its website.

Our unique position near major plate boundaries in the Southern Ocean means that we are overlooking our responsibility to detect tsunami events in our economic zone for the purposes of alerting our own population and government agencies in nearby countries.

Confusion Reigns
It would appear that even the organisations involved with assessing tsunami events in New Zealand waters don’t know who is responsible for reporting them.

GeoNet’s tsunami page provides links to the NIWA website and the Pacific Tsunami Warning Centre.
The GNS Science website’s tsunami page has very useful background information on tsunami but offers no links to outside agencies.
The NIWA website tsunami page has links to a map of its coastal sea-level network, the U.S. National Oceanic and Atmospheric Administration and the Ministry of Civil Defence and Emergency Management.

The Ministry of Civil Defence and Emergency Management, which is responsible for issuing tsunami alerts to the general public of New Zealand, makes no effort whatsoever to provide direct access to locally relevant information on current tsunami events on its website.

Its link page for tsunami information has two dead links to the International Tsunami Information Centre, and otherwise passes the buck to NOAA and the Pacific Tsunami Warning Centre.
Its page for media releases contains selected information, but well after the event.

MCDEM needs to review its communication processes and make use of modern technology to fulfill its obligations to inform, advise and direct in an open and public fashion.

One Response to “The Puysegur Trench Quakes of 30-9-2007 – Part 3”

  1. bruce says:

    Excellent and well-balanced appraisal in my view. The lack of immediate communiques from the authorities is appalling.

    One can only think of the crass difference between NZ and Japan. Japan has learnt from past tragedies.. it seems like we are still waiting for ours to happen.

    BTW excellent website! I check it daily.

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