[time-nuts] Freestanding mast
Hal Murray
hmurray at megapathdsl.net
Tue Sep 7 08:19:38 UTC 2010
sar10538 at gmail.com said:
> The mast could have sunk a bit or even this whole area could have done as I
> live on reclaimed marsh-land. My Mothers 3 year old house looks like it has
> sunk a bit at one and and risen at the other, ie. it looks like it has
> tipped slightly as her house is built on a concrete pontoon.
It's not off scale to move a meter vertically, but I can't find anything that
makes me think it's likely in this case.
If something like that happened due to construction on a marsh, I'd expect
there would be a lot of disruption on the local surface, that is the local
vertical displacement would not be uniform. But you wouldn't see that if a
large corner of a plate moved up or down.
If there was a large vertical displacement, we should be able to find
something in a news report, or maybe some better info will appear in a week
or month after the local geology geeks have collected more data and analyzed
it carefully.
(The data from the Chile quake was very very good, but they had a major data
gathering setup in exactly the right spot.)
This news story at:
http://preview.tinyurl.com/24y8e7a
http://www.dailymail.co.uk/news/worldnews/article-1309194/
New-Zealand-earthquake-moves-Earths-surface-11ft-right.html
says 11 feet horizontal and
Roger Bates, whose dairy farm at Darfield was close to the quake's
epicentre 19 miles west of Christchurch, said the new faultline had ripped up
the surface across his land. `The whole dairy farm is like the sea now, with
real soil waves right across the dairy farm.
`We don't have physical holes (but) where the fault goes through it's been
raised a metre or metre and a half.'
Another URL:
http://preview.tinyurl.com/3xnf43u
http://www.gns.cri.nz/Home/Learning/Science-Topics/Earthquakes/
New-Zealand-Earthquakes/Where-were-NZs-largest-earthquakes
says:
The biggest NZ earthquake - magnitude 8.2 Wairarapa earthquake in 1855.
On an international scale, the 1855 earthquake is of major significance in
terms of the area affected and the amount of fault movement. About 5000km2 of
land was shifted vertically during the quake. The maximum uplift was 6.4m
near Turakirae Head, east of Wellington. The maximum horizontal movement
along the fault was about 18m. This is the largest displacement along a
vertical fault line ever recorded!
Ahh... Here is a URL that says "variable vertical movement of up to 1 m"
http://preview.tinyurl.com/3ysb4ta
http://all-geo.org/highlyallochthonous/2010/09/
tectonics-of-the-m7-earthquake-near-christchurch-new-zealand/
Time sink warning, there are good links on that page. In particular, lots of
good pictures here:
http://www.crashbang.co.nz/quake040910/index.html
For the 1989 Loma Prieta (San Francisco) quake, the local photographers
donated lots of good pictures and they made a couple of picture books.
Profits went to the needy.
--
These are my opinions, not necessarily my employer's. I hate spam.
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