Wednesday, July 06, 2011

Earthquakes in New Zealand

Yesterday there was much fun in Melbourne yesterday as the city got a little jolt from an earthquake.

Meanwhile a larger earthquake hit New Zealand yesterday - a 6.5 up near lake Taupo.

A better way to put these events in perspective is to look at the respective geo-science resources. Australian and regional earthquakes are mapped by Geoscience Australia. The map (done for the region showing all earthquakes in the last month) is most remarkable for the very few dots over Australia and the small size of them.

For some reason the Taupo earthquake isn't showing on the Australian map. But the NZ equivalent resource lists recent earthquakes. The one I'm talking about is reference number 3540736. The number of quakes they have this will be off their recent list soon.

The reality was this was a big quake, but it was very deep and a long way away from built up areas. But New Zealanders are being reminded of the risks.

As the story notes;

At 150km deep and 30km west of Taupo, the damage from the latest big earthquake to hit New Zealand was minimal....A major movement on the Wellington Fault - which does happen every 100 years or so - is likely to result in an earthquake measuring about 7.5 with surface rupture of over 50km. Compare this with the September 4 Darfield quake which caused a 29km rupture that was mainly across rural Canterbury land.

To these risks we should add the risks of volcanic action in New Zealand - far greater than the risk reported today of an Aussie volcanic eruption.

While the warning about risk management was to Kiwis, major volcanic or earthquake activity in Australia will be felt by us just as if the Kiwis hadn't made their big mistake of 1900 and not joined the Federation.

Australia's disaster planning needs to cover both the direct and indirect effects of one of these New Zealand disasters. It is not a matter of if, but when. Despite the comments of scientists and others about periodicity we cannot know when - it could still be hundreds of years away - or it could be tomorrow.

Novae Meridianae Demetae Dexter delenda est

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