18 Palert seismic monitoring system units will be installed at nine locations between Maketu and Waihi Beach.
18 Palert seismic monitoring system units will be installed at nine locations between Maketu and Waihi Beach.
An earthquake early warning system that provides a precious cushion of reaction time before the destructive shaking arrives is being trialled in the Western Bay of Plenty.
The Western Bay District Council has commenced installing the Palert seismic monitoring system that measured an earthquake's P wave - the wave thathit shortly before the S wave which everyone felt.
Kelvin Hill, the council's utilities manager, said 18 units were being installed at nine locations between Waihi Beach and Maketu.
The Palert seismic switch unit.
The $2500 units were being fitted to key infrastructure such as water and wastewater pump stations and triggered automatic shut-off valves before the destructive shaking began.
Mr Hill said the system also allowed the council to build a quick snapshot of which areas would be hit hardest by a major quake, given it was unlikely that the whole of the Western Bay would be impacted equally.
"It is a bit of advance warning, but if it's a decent earthquake, you will soon know about it," he said.
The Palert seismic switch unit.
Keith Swasbrook, the business development manager for the Palert seismic switch, said the system could accurately determine the magnitude of an earthquake, its direction and how far away the S wave was.
Although it was still early days in New Zealand, the switches could eventually provide an early warning to protect people and infrastructure throughout the country.
He explained that the P wave from an earthquake centred 200km off the Bay of Plenty would be detected 37 seconds before the destructive S wave arrived, with the alert time shortening or lengthening according to distance from the epicentre. The P wave moved nearly twice as fast as the S wave.
Councils with half-dozen strategically spaced Palerts could triangulate the readings to calculate the distance from the epicentre of an earthquake.
The ultimate goal was a nationwide early warning system via large numbers of units linked to centralised computer servers, but so far only Wellington, Whakatane and the Western Bay of Plenty were installing the units.
He said the system had operated for nearly 10 years in Taiwan, especially in schools. Taiwan's early warning system meant that even a short 10-second alert was enough time for office workers to perform essential survival tasks like wedging open a door, turning off gas and electricity and crawling under a table.
Data from Palert sensors could also be linked to transport systems so trains automatically slowed down.
However, the system could not predict whether an earthquake would generate a tsunami.
Tauranga councillor Steve Morris said the Palert system was not what he was looking for to buy more time for Tauranga's coastal residents to escape a tsunami. Palert was more about giving warning to get under a table, whereas his campaign was to dramatically reduce the one hour it took to activate a tsunami alert because of the "decision-making tree" followed by Civil Defence.
Cr Morris said the Bay's Civil Defence Emergency Management Group will meet early next year to consider his request for an improved response system, including $250,000 monitoring buoys capable of delivering a much earlier warning of the size of a tsunami generated close to New Zealand.
"Palert is a good idea but it is not a priority for us."
