Kiwi quake monitoring goes modern

Kiwi quake monitoring goes modern

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Tourists who climb Tongariro, New Zealand, a crumbled mountain at the heart of New Zealand’s volcanic plateau, can see the remnants of past eruptions everywhere. The trek, billed as New Zealand’s greatest one-day walk, allows hikers to walk beside emerald green lakes, down steaming hillsides and across vast craters. In New Zealand, you really know you and the earth below are alive.

“The beauty and the spectacle is part of the deal,” says Hugh Cowan, the scientist in charge of a new project to monitor New Zealand’s seismic activity. “The flip side is we need to know what we are living with.”

What they are living with are earthquakes, volcanoes, landslides, tsunamis and geothermal activity.

But despite New Zealand’s geological hazards, the equipment that monitors the country’s natural phenomenon is rundown and out of date. The backbone of New Zealand’s seismographic network has been diligent farmers who have looked after the magnetic tape cartridges that record the country’s seismic activity.

“Land owners around the country faithfully change these cartridges every week and mail them to us in the post and we read these tapes and integrate that data. It therefore takes … literally six to nine weeks to build up and reconstruct the pattern of shaking associated with any large event,” Cowan said.

But now GeoNet, a 10-year program costing $40 million, is upgrading the equipment that monitors earthquakes and volcanoes in New Zealand. The program links seismic monitoring stations to two round-the-clock data centres. The farmers will still have stations on their land but, says Cowan, “they won’t have to do anything because the signal will come to us automatically.”

So far, GeoNet has implemented 40 percent of the upgraded seismographic network infrastructure and has installed 85 percent of a new strong motion network. Mobile communications, satellites and landlines will transmit the data to the scientists. It is New Zealand’s largest commitment to scientific equipment in decades.

For New Zealanders, GeoNet will offer practical help when the big one hits. The new network means the scientists will be able to tell just how big the earthquake was; previously, instruments would be saturated by anything over a magnitude of 7.

GeoNet will also be using a GPS to monitor tiny movements in the Earth, such as the swelling that can precede volcanic eruptions. Other quake-prone areas, such as California and Japan, have already installed the sort of seismic equipment that New Zealand will be progressively installing over the next few years. But New Zealand has distinguished its program by combining five disciplines — seismology, volcanology, geochemistry, engineering geology and geodesy — into one operation.