Earthquake and Volcano Safety

Charming. :-/

That can sound really scary to many immigrants. Living here feels a bit different, though - maybe there will be a big disaster soon but we've heard it so many times. There is also a feeling of "we'll be fine" and that there is no benefit in worrying oneself sick about it. It is a bit like using the London Underground - everyone knows it could be hit by terrorism but it doesn't put people off ... life has goes on.
:)

Volcanic earthquakes mystery to scientists
27 October 2006
By MIKE WATSON

A series of small volcanic earthquakes on Mount Ruapehu and Mount Ngauruhoe has scientists baffled as to what may be brewing underneath the peaks.

Several small volcanic earthquakes have been recorded on both mountains in past months and scientists are unsure if they are a prelude to something bigger. Both mountains are at alert level one, which means there are signs of activity.

Geological and Nuclear Sciences duty vulcanologist Ken Gledhill said three small volcanic earthquakes were recorded on Mt Ruapehu earlier this week.

The earthquakes measured around magnitude two and were smaller than the 2.8 magnitude earthquake which had caused the lahar early warning system near the crater to be activated on October 4, he said. "The signs are there that the mountain is doing something, and it is possible it is returning to the behaviour noticed before the 1995-96 eruptions."

Mr Gledhill said Mt Ruapehu had a history of erupting with very little warning. The crater lake temperature had been fluctuating, which did not necessarily indicate another big eruption was imminent.

Conservation Department readings yesterday at the crater showed the lake level and temperatures had risen significantly in the past fortnight because of hydrothermal activity.

"The signs are slightly different from a few months ago and we are keeping an eye on lake temperature, seismology and visual observations. When you get magma and a geothermal system with a crater lake on top it becomes complicated.

"There's a lot of energy involved heating and cooling the lake and there will probably be activity carrying on."

There had been signs of small volcanic earthquakes on Mt Ngauruhoe since May. The mountain last erupted in 1974 and steam from fumeroles at the crater rim had been increasing since last year.

- The Dominion Post

Oooh, how exciting!

This link has been on before, but anyone who wants to see whatever action is about, go to http://www.geonet.org.nz/volcanocam.html

Unfortunately you can't see much at this very particular moment - just lots of low cloud obscuring the volcanoes. The seismic drums don't even show much activity. Still ... could change.

:)

Head south for some action. Has the earth moved for you yet, Nick?  

South Islanders warned earthquakes on the way
21 November 2006
By PAUL GORMAN

South Islanders could be shaken by more earthquakes over the next week or two, but geologists say they are unlikely to be major. Four tremors in three days have rocked the top half of the South Island, two in the outer Marlborough Sounds and two in North Canterbury.

Picton residents were jolted awake at 3.38am on Saturday by a tremor measuring 5.5 on the Richter Scale and centred 40km north-east of Picton, 70km deep. That followed a quake in the same location on Friday morning, 50km deep and with magnitude 4.6.

In North Canterbury, a 3.5 magnitude tremor 30km deep near Rangiora shook parts of the region at 8.06pm on Saturday, while another tremor of 4.3 located further inland, about 40km east of Arthurs Pass, and only 7km below the surface, was recorded at 3.47am on Sunday.

The three weekend quakes were all felt in Christchurch.

GNS Science duty seismologist Bryan Field said small earthquakes often occurred in clusters.

"You can expect maybe a few more, it's very possible, but I don't think they would be too much bigger. It's fairly unusual to have three felt in Christchurch in as many days, but I wouldn't get too alarmed about it."

Field said GNS was not aware of any reports of damage. However, he said the Crown research institute had received nearly 600 reports from people who had felt the Picton earthquake, from Raurimu in the North Island to Lyttelton.

There were 91 reports of the Saturday evening event, felt from Rangiora to Charteris Bay, and 19 reports of the Sunday morning tremor, felt from Reefton to Cashmere.

Associate Professor Jarg Pettinga, of the University of Canterbury's geological sciences department, said much of North Canterbury was underlain by faultlines.

"It's a reminder that we are in a seismically active region and that these sorts of events are to be expected on an annual basis."

- The Press

Looking for a new pet, anyone? ? :o

Head-banging snakes may predict China quakes

BEIJING: China has come up with an earthquake prediction system which relies on the behaviour of snakes, state media has said, two days after two quakes struck off neighbouring Taiwan.

The earthquake bureau in Nanning, capital of the Guangxi autonomous region in southern China, had developed its system using a combination of natural instinct and modern technology, the China Daily newspaper said.

Experts at the bureau monitor snakes at local snake farms via video cameras linked to a broadband Internet connection. The video feed runs 24 hours per day.

"Of all the creatures on Earth, snakes are perhaps the most sensitive to earthquakes," bureau director Jiang Weisong was quoted as saying.

Jiang said snakes, a popular restaurant dish in the south in the winter, could sense an earthquake from 120km away, three to five days before it happens. They respond by behaving strangely.

"When an earthquake is about to occur, snakes will move out of their nests, even in the cold of winter," Jiang was quoted as saying.

"If the earthquake is a big one, the snakes will even smash into walls while trying to escape."

China is struck by frequent earthquakes, with most hitting remote rural areas.

Two people were killed and 42 injured on Tuesday when three buildings collapsed in earthquakes that shook southern Taiwan.

While a tsunami warning came to nothing, the quake damaged undersea telecommunication cables, affecting users across Asia.


:)

Editorial: A totally predictable mishap
Thursday January 04, 2007

For the past couple of years, the world's volcanologists must have watched developments on Mt Ruapehu with a high degree of interest and no little puzzlement. It is not often they have the opportunity to scrutinise a totally predictable mishap.

But, with the mountain's crater lake now only 2.8m below the top of a dam of ash and rocks formed by the 1995-96 eruptions, there is a strong possibility that, some time in the next few weeks, it will burst and one million cubic metres will sweep down the Whangaehu Valley. That would be a lahar almost twice the size of the one that caused the Tangiwai disaster in 1953 in which 151 people on an overnight train died - enough to capture anybody's attention.

The volcanologists' bemusement relates to what New Zealand has done, or, more precisely, not done, to prepare for this inevitability. In 2003, it was suggested the mudflow could be controlled if bulldozers were to dig a 100m trench, thereby allowing the lake water to drain harmlessly. This apparently straightforward $200,000 job was rejected by the Minister of Conservation, Chris Carter, on the grounds that it would be dangerous for those who did the work.

Maybe so, but the minister did not say it would not work. More likely, he was swayed by the opposition of local iwi, who maintain crude cuts in the mountain's summit would be an affront to their spiritual values.

The world's volcanologists have, therefore, watched as a cultural hurdle to a piece of engineering that would avert a potentially devastating lahar has produced a decision based on political factors. It must surely have made no sense to them, and it will make no sense to those whose livelihood and, possibly, lives are threatened when the inevitable happens. A channel should have been dug in 2003-04, when it could have gone through solid older lava. Now, it would have to pierce the much weaker dam dumped by the 1995-96 eruptions. But that should not be ruled out if the burst does not occur this summer, delivering a probable year's reprieve.

Instead of taking the logical course, the Government has concentrated on bolstering safety measures. These include strengthening bridges and installing an alarm system that warns a lahar is on the way. Response plans have been prepared to evacuate the area and close all at-risk bridges, roads and railway lines, and a 300m-long stopbank has been built to stop the lahar spilling into Lake Taupo's catchment.

This is all well and good. But nature specialises in confounding such planning. It never acts quite as expected. If the lahar occurs as predicted, there may, indeed, be minimal damage and no loss of life. But what if it were triggered by a major earthquake that also disrupted the early warning system? At best, such systems provide only a limited warning - 90 minutes in the case of a mudflow rushing towards the Tangiwai bridges. They do not stop infrastructural damage, or organise the evacuation of an area that is often thickly populated with trampers, canoeists and skiers.

Local authorities in the area have long doubted the chances of an effective evacuation. They were strong advocates of a trench. They have complained about cultural concerns being given a higher priority than the risk to life. It is they who will have to pick up the pieces after the lahar has done its work. Having had their advice rejected, they will have good reason for seeking multimillion-dollar support from the Government.

Scientists, for their part, will get the rare opportunity to observe a natural process unhindered by human hand. Doubtless, they will be grateful for the opportunity. At the same time, they can marvel at the eccentric thinking that allowed this to happen.

- NZ Herald

For anyone who's keeping a wary eye on the happenings on Mt. Ruapehu here's an updating site that explains what's happening.

Hi MB,

That link to Mt. Ruapehu doesn't work.

:)

Sorry Glenda. I ended up with 2 links for this, one that worked and one that didn't. Must have put the wrong one in ::) . Having a(nother) bad PC day today. ::)

Hope the link will work now.

Mt Ruapehu lahar now tipped for April
11:05AM Friday March 02, 2007

The much-anticipated lahar at Mt Ruapehu appears to have been delayed.

The Department of Conservation says water levels in the crater lake have dropped slightly over the past month due to a prolonged fine spell during February.

A DoC spokesman said the water seepage through the tephra dam has not picked up speed and it is now thought the lahar could happen later this month or possibly in April.

- NEWSTALK ZB

From here .