By Iain MacIntyre
Upgraded Civil Defence manning provisions and media liaison policies should see the general public better informed about, and faster able to evacuate from, future offshore-generated tsunamis.
 As reported in the Spring 2006 issue of our sister publication ISN, an automated ‘potential’ tsunami alert issued by the Pacific Tsunami Warning Centre in the early hours of 4 May that year led to an unprecedented misinformation frenzy.
Having established a tsunami had in fact not been generated, Civil Defence did not proactively inform the local populace of the situation at that time. However, panicked phone calls made by friends and family viewing incorrect overseas media reports ultimately led to hundreds of East Coast North Island residents fleeing to the hills.
Improvements to the system
Civil Defence public information manager Vince Cholewa says the range of improvements recently introduced by the organisation mean this situation should not be repeated. “We now have Civil Defence staff in the Northern Communications Centre 24 hours per day – not just on call,” he says.
“They receive information from the Pacific Tsunami Warning Centre, GNS Science, MetService, NIWA and a whole range of agencies and organisations. They work through decision-making criteria. Information comes in, for example, about an earthquake and a series of questions – magnitude and location etc – go through to decision points.” Parallel to this operation, Civil Defence has a duty team in Wellington which is also on 24-hour call.
“Some of those decision points involve contacting the duty manager,” Mr Cholewa explains. “Others involve immediate actions, which include issuing warnings or advisories that go to about 400 addresses. The very first initial statement – which could be there is a tsunami risk, no tsunami risk or there is a potential tsunami – must be issued within 15 minutes. The duty team must also activate the National Crisis Management Centre within half an hour.”
Overall, Mr Cholewa says the National Warning System itself is now better manned, faster, has improved IT facilities, and significantly better linkages to science agencies, including the capability to convene the Tsunami Expert Panel virtually immediately.
Doing something about it
Furthermore, he says the Civil Defence Emergency Management Act has prompted local city and district councils to develop a range of tsunami alerting, signage, evacuation and mapping systems based on their areas’ particular needs.
While acknowledging the improvements made in this area by Civil Defence, Wellington Harbourmaster Mike Pryce points out the biggest local potential tsunami risk would be from a nearby event. “Warnings from distant events are, as before, issued from the Pacific Tsunami Warning Centre,” he says.
“Any local earthquake would produce effects too quickly for adequate warning, and a severe local earthquake should be warning enough that a local tsunami might be formed. It is a very inexact science, but there seems to be a public/political expectation of wanting to be seen to ‘be able to do something about it’!”
Port companies around the country contacted by FTD confirmed they have active tsunami response plans which would be activated by the National Warning System.
Tsunami gauges
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| Tsunami monitoring stations: Locations of the 20 pressure sensing gauges that will form a national tsunami monitoring network. The network is designed to measure wave heights and it is not, on its own, a tsunami warning system. It will be fully installed by 2010. |
In a related development, Land Information New Zealand (LINZ) and GNS Science are in the throes of installing sea-level tsunami gauges at five offshore locations and 15 coastal sites throughout the country. Sensors inside the gauges, which will be fully installed by 2010, measure changes in water pressure which relate directly to the wave height above them.
The offshore installations will specifically provide information about the size and possible arrival times of incoming tsunamis from distance sources, whereas the coastal gauges will detect the first landfall of tsunami waves.
The latter will also enable an ‘all clear’ to be signalled if a large undersea earthquake has not produced a tsunami, or if a near-shore earthquake has generated only a small wave.
With data continuously relayed to GNS Science in Lower Hutt, wave height information will be freely available through the GeoNet website. In the event of a tsunami reaching the coast, information from the network will be promptly relayed to civil defence agencies to enable their response to be focused on the most affected areas.
Contributing to the international tsunami monitoring network, data from the sea-level gauges will also be shared in real time with tsunami warning centres around the Pacific.
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