Harsh reminder to be prepared

By Michele McPherson

An earthquake as destructive as the one that hit Christchurch this week could happen in Tauranga.
Warwick Murray, Civil Defence group controller for the Bay of Plenty, said it was certain that a large earthquake would rock the Bay some day.
"It will happen here. I don't know when. It might be tomorrow, it might be in another several hundred years.
"We have to be prepared for it."
Mr Murray said the Bay of Plenty was on the main tectonic fault line between two tectonic plates, in a highly active zone for volcanic and tectonic movement.
"The potential for a large earthquake is there and if we have an earthquake that is of equivalent magnitude to the one that's just happened in Christchurch, that is that close and that shallow to centre of population, then we can expect to have significant damage," Mr Murray said.
GNS vulcanologist Craig Miller said it could not be ruled out that a major quake would hit Tauranga.
There were faults in the Bay of Plenty capable of generating earthquakes of that size, he said.
"We know that with Edgecumbe [1987 earthquake]."
Mr Miller said the Edgecumbe earthquake was of a similar nature to the February 22 Christchurch quake.
Although the damage in Edgecumbe was far less than the devastation seen in Christchurch, that could be because "it didn't happen under a city".
"It [Edgecumbe] was fairly destructive, but it was in an area that was predominantly a rural area. The infrastructure was quite severely damaged."
The quake that rocked Christchurch on Tuesday was 6.3 in magnitude and had a shallow depth of 5km.
At its worst, it was 9-10 on the Modified Mercalli (MM) Scale, which measures the intensity of shaking that would be felt.

The MM scale goes from 1 to 12, with 12 being the most severe.
The Edgecumbe quake has similar statistics - it was of 6.6 magnitude, 6km depth, and MM9.
"It was lucky there wasn't a city built on top of it," Mr Miller said.
If a major quake hit the Bay, liquefaction similar to that seen in Christchurch would be an issue.
Liquefaction happens when sandy soil is shaken violently, causing water to rise through its pores.
Scientists compared liquefaction in the September 4 earthquake to jumping on wet sand at the beach, it soon turns to a murky soup.
"The flat-lying parts such as Papamoa and Tauranga that are built on silty and sandy sediments are going to be the ones that could be affected by liquefaction," Mr Miller said.
The Bay of Plenty Civil Defence Emergency Management Group plan includes a "hazard scenario" of the effect of a magnitude 7.6 earthquake generated by abrupt movement of a fault in the North Island Shear Belt.
Typically, these earthquakes occur 5km to 30km beneath the Earth's surface.
Such an earthquake would see extensive damage in Whakatane and Opotiki, with Western Bay areas including Tauranga and Te Puke damaged to a lesser degree.
All lifeline infrastructure, generators, phone and power, would be disrupted to varying degrees.
Whakatane would be worst hit, with estimations of 30 deaths and many injuries in the commercial area.
Mr Murray said the Christchurch quake was a reminder to be prepared.
"It's one of these classic human situations where we don't really want to entertain the possibility, and we kind of put it out of our mind when things are quiet, so it's kind of hard to get people to think about it and get prepared for it.
"It's really only when we get tragedies like this happen so close to home it forces us to think it could happen."
Mr Murray said some Christchurch residents who did not have emergency kits would be suffering. "In the Christchurch situation, a large amount of energy and effort is going into rescues. The reality is there an awful lot of people we are not hearing about who are struggling on a day-to-day basis."
Mr Murray said it was necessary to be prepared to survive for several days without a water supply and electricity.
"You have to think about how you would cope in these first few days after a major earthquake."
Tauranga's high-rise hotels and second harbour bridge have been built to withstand the impact of a large earthquake.
Mr Miller said buildings constructed to modern earthquake standards had "actually survived pretty well" in Christchurch.
For more information on how to get prepared, see this website.

- Bay of Plenty Times

© Copyright 2014, APN New Zealand Limited

Assembled by: (static) on production apcf03 at 20 Dec 2014 03:23:24 Processing Time: 547ms