Earthquakes

[LilAmy]

OK got to share this one with you all.

Last Friday I experienced my first proper Earth Quake since arriving here.

We were sat at work then all of a sudden there was this jolt, the office wall moved, my desk and PC swayed and I moved on my work chair about an inch. I was all surprised and excited when I found out what it was.

Everyone else in work just acted all normal but cos it was my first I was straight on email and phone telling everyone.

The quake was actually in the South Island but was felt all over Wellie and the suburbs. My poor mum nearly had kittens when I emailed her telling her about it all :)

[Glenda]

How exciting!!!

We don't get anything like that up here, nothing of any shake-value since the 1960's. Apparently we had some just 30km north of us but they missed any rattle of the crockery (my kids make more vibration running round the house).

Think you can definitely expect more. Have you plenty of blue tack to stop your fragile things jumping about, and screwed your bookcases to the walls?

You will have to explain to your mum that the buildings here are earthquake-proof. [smiley=eusa_whistle.gif] [smiley=eusa_pray.gif] My mum did panic a bit, though, when there was that threat of a tsunami after the Fiji earthquake. Had to explain we lived well above sea-level. ::)

:)

[MotherBear]

You'll know when you're a seasoned NZer, Amy. You'll be like the others and continue working without batting an eyelid whenever there's an earthquake. Exciting to experience it and something to share with those back home (except Mums, of course ).

Three-day tsunami hits NZ coast
23 November 2006
By KENT ATKINSON

New Zealand has been hit by a tsunami travelling at the speed of a jetplane - but few people noticed despite the wave bouncing around the coast for three days. The tsunami - triggered by a big earthquake in the Kuril Islands in Russia's Far East - hit on Thursday last week, and was still affecting parts of New Zealand on Saturday.

The magnitude 8.3 earthquake, at 11.14pm on November 15 (NZST) was on a subduction zone where one tectonic plate overrides another between Japan and Russia's Kamchatka Peninsula.

The journey of more than 9600km for the initial wave took just over 14 hours to reach the Bay of Plenty and Chatham Islands - an average speed of about 685kmh - but a bit longer for the South Island, said Rob Bell, principal scientist at the nation's National Institute for Water and Atmospheric Research (Niwa).

Waves more than half a metre high were recorded by two of the seven sea level gauges on the east coast of the South Island and the Chatham Islands ? the rest of the gauges were 35cm or less.

Dr Bell said the tsunami then bounced off undersea ridges and moved to and fro along indented sections of coastline. "This explains why the highest waves ... occurred just over 40 hours after the first wave arrived in New Zealand waters," he said in a statement.

The tsunami waves were recorded by several sea level gauges including those at Timaru, Lyttelton, Sumner Head (Christchurch), Kaikoura, and on the Chatham Islands. The gauges are operated by Niwa, Port of Timaru and the Port of Lyttelton. The largest wave heights were 56cm at the Chatham Islands on November 16, and 58cm at Timaru on November 18.

Dr Bell said New Zealand was never in any real danger even though the earthquake was large: "The subduction zone in the Kuril Islands is orientated to beam more directly at Hawaii, US Pacific coast, and Central America."

The tsunami impact was greatest at Crescent City in northern California, where a peak wave height of 1.76m caused strong surging currents, resulting in more than $US1 million ($NZ1.17 million) in damage to docks, slipways, floats and electrical equipment.

- NZPA

[alifox]

:-X Have only just been discussing NZ's history of earthquakes etc with a friend who is also thinking about NZ as a place to settle. I didn't know about THIS tsunami, but explained that a big one had been predicted, as have other natural events, like volcanic erruptions. Think that Iv'e scared her off the prospect a little, but Ive tried to explain that contingency proceedures are in place in case of " A BIG ONE", and that most of the in-land areas should be alright. Does make you wonder whether you are crazy to consider such a potentially unstable place for a home :-/ I know the quakes are generally quite mild, it does definately make you more cautious in deciding for NZ. Will still probably go for it, as it cant be as bad as UK's congestion/ rat-race lifestyle/ inflated economy etc! ;)

[selchie]

Having lived in earthquake country all my life, I must say that a specific area rarely experiences many disastrous quakes. I think that the fear of them is usually worse than the reality. Yes, I've been at the edges of quakes that have been disastrous closer to the epicenter, but I've only experienced the loss of one wine glass in 46 years. That quake was frightening, but really not that bad damage-wise.

Lil Amy's report reminded me of one quake I experienced. I was in a cafe with friends when the ground began to do the shim-sham. Many of us made remarks like "oh, wow", wondering how big it would be. After it subsided, a waiter stood up from behind the counter where he had been doing something, and asked what we were all fussing about. We told him about the quake, and he was quite disappointed. He had recently moved to California, and just missed feeling his first earthquake.

[Glenda]

:-X Have only just been discussing NZ's history of earthquakes etc with a friend who is also thinking about NZ as a place to settle. I didn't know about THIS tsunami, but explained that a big one had been predicted, as have other natural events, like volcanic erruptions. Think that Iv'e scared her off the prospect a little, but Ive tried to explain that contingency proceedures are in place in case of " A BIG ONE", and that most of the in-land areas should be alright. Does make you wonder whether you are crazy to consider such a potentially unstable place for a home :-/ I know the quakes are generally quite mild, it does definately make you more cautious in deciding for NZ. Will still probably go for it, as it cant be as bad as UK's congestion/ rat-race lifestyle/ inflated economy etc! ;)

Earth Sciences is a pet interest of mine and I worry that what I find interesting is scary for someone else. ?Hence I often wonder if I should keep quiet. ? :-X

I have four children who are reliant on me and I certainly would not put them at risk by moving to an unstable and dangerous country. ?As you say, it cannot be as bad as the UK's congestion/rat-race etc.! ::)

You could mention to your friend that big earthquakes have happened in the past in the UK, though rare. ?Would definitely not want to be there if another happened. Quite a few European countries often have them (like the 90,000 who died in Portugal in 1755 from an earthquake and tsunami). ?Italy and Greece have volcanos thrown into the equation too - and these have not been a disadvantage to their history. ?Japan has also lived with both risks for many thousands of years. ?

As you know, millions of people live in such areas around the world, and they accept the risk as the chances of experiencing a 'big one' is remote. ?Some of these people live in poor areas and build unsafe stone or concrete houses. ? New Zealand is, however, actually one of the safest countries to be in during such activity as not only is there considerable monitoring of the earth's movements here and around the Pacific for tsunamis, but the buildings are generally earthquake-proof and the population (to a degree) ready for such an event. ?

Earthquakes, small and large, will occur in many parts of New Zealand but in the areas more prone you are talking at least 100-200 years between the larger ones. ?Some parts of the country rarely experience earthquakes - Northland for example can expect an earthquake 'felt by everyone' every 1,000 years and ones causing slight structural damage every 7,000 years; the Dunedin area is similar. ?Places like Wellington would expect these two intensities every 9 and 42 years. ?

The 'big one' they regularly talk about in the media usually means a big one in Wellington, or one in the South Island where the two plates which slide alongside each other in the Alps have been 'locked' together for so long that they expect a jolt at any time to release the stress they expect there. ?There was a big earthquake near Wellington in 1855, which was a wake-up call for the new settlers, and there have been other ones in nearby areas (like Malborough) which have caused damage in Wellington. ?The threat of a 'big one' has not discouraged the government of New Zealand being based in Wellington, though. ? Considering the time scales involved, these earthquakes might not happen in either yours or your children's lifetimes! ?(I emphasise the 'might not' !!! ?::)) ?

Because of earthquakes around New Zealand and countries as far away as the other side of the Pacific, tsunamis have happened in the past - from just an slight increase in sea-level to tsunamis several metres in height. ?You won't hear much about them as the last one of any note was in 1960 after a massive earthquake in Chile, and that only affected some coastal areas. ?Fortunately, we are part of the Pacific Tsunami Warning Centre and hoped to be warned in advance of any tsunami, though the warning will not be quick enough in the event of a large local quake. ?Although we quite often visit beaches, I personally would not feel comfortable living at sea-level along a coast. ? ? ? ?

Volcanic action is quite probable every five years or so, but more predictable than earthquakes, so more warning given. ?The volcanoes that have a recent history of erupting are conveniently placed in the centre of the North Island around Taupo and Rotorua. ?Another that supposedly erupted in the 1700's is Taranaki. ?White Island in the Bay of Plenty is permanently active but of little concern - because of it's activity. ?No one is put off living in or visiting these areas ... you can visit the craters, climb or ski on the volcanoes' slopes. ?

There is the occasional story in the media about Auckland's (and Northland's) volcanic histories. ? Auckland has about 49 extinct volcanoes and it is quite possible another will be added to the list. ?The last to pop up was Rangitoto some 600 years ago. ?As you can gather, it could be another, say, 500 years or more before such an event ever happens again but, if it does, the eruption will most probably be predictable, small and short-lived ... a tourist attaction. ?::)

I think the people here have been brought up with their geophysical history and almost look forward to something happening(!). ?Most of the time much doesn't happen at all. ?Hope I've given you some useful info and ammunition!
:)

[MotherBear]

Hope everyone's OK in BOP and all your fragile ornaments and nicknacks are still intact.

Sharp earthquake shakes Bay of Plenty
9.25am Tuesday December 5, 2006

An earthquake measuring 5.1 on the Richter scale was felt sharply in eastern Bay of Plenty this morning.

The quake, just before 8am, was centred 30km southeast of Opotiki at a depth of 40km and felt as far as Gisborne, according to a preliminary report from GNS Science.

An Opotiki police spokeswoman said the quake had been a strong jolt, but no reports of damage had come through by 9am.

It was preceded early this morning by a smaller earthquake felt in the Pongakawa Valley.

The 2.3 quake, at 4.44am, was centred about 20km northwest of Kawerau, at a depth of only 2km.

- NZPA

Strewth, I thought they meant in the last day or two. :o They could have phrased it a bit better.

Seven eruptions have covered Auckland in ash
Saturday January 13, 2007

Auckland has had seven volcanic eruptions which have buried the area now occupied by the city under more than 10cm of ash, research has revealed.

"That amount of ash would cause chaos in Auckland," said GNS Science volcanologist Graham Leonard. "From a hazard point of view, that is pretty significant".

The research - which casts new light on volcanic threats to the area - springs from a drilling programme in the area.

More here .

Strewth, I thought they meant in the last day or two. :o They could have phrased it a bit better.

No kidding.

Four earthquakes shake east coast
NZPA | Monday, 22 January 2007

The North Island's east coast has been hit by four earthquakes measuring 4 or more on the Richter scale in the past two days. All the quakes were located in the same place - 30km east of Ruatoria at a depth of 12km.

The latest two shook the region within a minute of each other this morning but there were no immediate reports of any damage. ?The quakes, measuring 4 and 4.1, struck at 11.12am and 11.13am.

Two other earthquakes, two minutes apart, shook the region on Saturday. The first recorded by GNS Science measured 4.2 and struck at 3.28pm. The second, measuring 4.3, came at 3.30pm.

GNS Science said there were no reports of damage.

From here .