Sunday, 20 May 2007

Moving plates bending, stretching NZ

is in warp time – and it’s shaking us up.
No, we haven’t stopped the clock or begun scorching through worm holes in space. Instead, our landmass is slowly distorting.
It’s because we living on the edge, says GeoNet project director Ken Gledhill.
“We live on the boundary between the Pacific and Australian (tectonic) plates,” he says.
Global Positioning Systems show how our island nation is being pushed and pulled by these underground forces (pictured).
“It’s like a scissor action,” he says. “Us in Wellington are getting crushed and the people in the Bay of Plenty are being pulled apart.”
He is of course talking of our body of land, not our human frames.
“Where I’m sitting the plates are pushing together 5cm a year,” he says.
“The main effects on the upper surface are earthquakes.”
The GeoNet website explains. “The Earth’s entire outer surface is like a hard shell, which is made up of smaller pieces called ‘plates’. Under New Zealand, two of these plates are colliding with huge force causing one to slowly grind under the other; this ongoing process causes our earthquakes.”
Since May 1, there have been more than 30 decent shakes in New Zealand – four of which have been in Taranaki.
The strongest local shudder was 4.2 on the Richter Scale, recorded at 6.43pm on May 13. It was a short, sharp shock centred 10km south-west of New Plymouth, was 10km deep and felt like a truck passing by.
Nationwide, the biggest tremor was more than 10 times stronger than the New Plymouth jolt. It hit Nelson in small hours of May 14, measuring 5.4 on the scale and was 90km deep.

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