Posted on 08/18/2003 10:13:11 AM PDT by blam
Week of Aug. 9, 2003; Vol. 164, No. 6
Large lake floods scoured New Zealand Sid Perkins
From Reno, Nevada, at a meeting of the International Union for Quaternary Research
Portions of New Zealand's North Island, like many volcanic regions, have experienced immense floods when lakes filling the craters of dormant volcanoes burst through the craters' rims. Now, scientists analyzing signs of erosion in the area have estimated the size of some of those powerful deluges.
Some of the largest such floods originated in Lake Taupo, says Vern Manville, a geologist with the Institute of Geological and Nuclear Sciences in Taupo, New Zealand. That 616-square-kilometer lake occupies the hole left when a volcano erupted about 1,800 years ago. In the decade or so just after that eruption, the surface of the lake rose to an altitude about 34 meters higher than today's level, says Manville. When the water eventually breached a large dam of ash along the crater rim, about 20 km3 of water rushed out and down the crater's slopes. In just a few weeks, the torrent—estimated to have carried up to 30,000 m3 of water per second—chewed a 12-km-long spillway and deposited layers of wet ash up to 17 m thick on the surrounding floodplain.
A similar but even larger flood occurred after an eruption 26,500 years ago, when about 60 km3 of water spilled from the lake, says Manville. That deluge ripped large boulders out of solid rock about 80 km downstream and carried them several kilometers further, suggesting a peak flow rate above 100,000 m3/s.
Today, the crater of nearby Mount Ruapehu, which last erupted in 1996, holds a rising lake. At current rates of water accumulation, the lake could breach the crater rim by 2007 and release a flood of up to 1.5 million m3 onto populated areas. But such a catastrophe need not occur if engineers stop the rise by constructing an erosion-resistant spillway in the natural dam, notes Manville. In 2002, engineers in the Philippines did just that at the lake accumulating inside the crater of Mount Pinatubo, which erupted in 1991.
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Go figure.
Fractionally before midnight at a place called Tangiwai, south of Taupo, a lahar from Mt Ruapehu's crater lake ripped through that area and whipped the train off a bridge over the river. It was New Zealand's worst rail disaster.
Ruapehu's crater lake is building up again. Sophisticated monitoring equipment won't stop another disaster but it will give sufficient lead time for people to get out of the area.
She wasn't the one who lost her fiancee to the disaster, was she?
,,, no, she wasn't. She met my dad in 1955, they married in 1957 and adopted me in October 1958. She died in 1972 from cancer.
Another notable New Zealand transport disaster occured in 1979 when an Air New Zealand DC-10 flew into the side of Mt Erebus, Antarctica.
That wasn't the one that was following a UFO light was it?
I do remember that crash; were they off course, or what ?
The Erebus disaster was in 1979. My dad and I were sitting watching something on TV after dinner when the programme was interrupted with an announcement about the DC-10 having lost contact. Everyone knew immediately it would result in confirmation of the worst with the next update. The info programmed into the flightdeck computer was incorrect.
As for the UFO light you mentioned, that was quite a story... a SAFEAIR Argosy was heading down the east coast of the South Island, near Kaikoura one night. I can't recall whether this was before or after the DC-10 disaster but around the same time.
Anyway, a cameraman named Crockett was on board by chance and he noticed bright lights out the window of the plane. He was amazed at the speed at which they were shifting. He started filming.
Air traffic control in Wellington had objects on their screens and were similarly astonished - they'd never seen anything like it and some operators immediately suspected faulty equipment. The pilot ran a dialogue with control to confirm what they were monitoring.
Within the next 24 hours if anyone in the developed world had never heard of New Zealand, that problem was solved. Crockett's film was whisked off to the US for thermographic processing/analysis and the whole thing was explained away to refraction of light from Japanese squid boats! You should see some of the wonderful sunsets we pick up on radar down here [LOL!]
On evening flights from Auckland thru Wellington I've seen squid boats working miles and miles out from New Plymouth - I'm talking way out. Squid boats don't work close to the coast.
I've never been to New Zealand,but I hope to make the Southern tour someday as I have fiends in Argebtina, Sri lanka, and New Zealand.
I have a good file system in my head...having friends of various origins helps to keep me alert to news from all over, I think.
,,, you're right. Try this for news... Disaters-R-us!
RUN! (or swim) FOR DEAR LIFE! :)
If I were you I'd be posting from Australia.
FReegards, FRiend.
Best wishes to you too LibKill.
Beats being drowned. Or Flamed. (ouch!)
Or you could move to Texas, but the heat at this time of the year is brutal. Even the Indian students at my school think it's a bit too much.
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