
Entire Japan coast shifted 2.4 metres, earth axis moves ten inches - kevruger
http://www.vancouversun.com/news/Japan+earthquake+factbox+Entire+Japan+coast+shifted+metres+earth+axis+moves+inches/4425617/story.html
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tokenadult
For someone who has lived through a massive earthquake (as I did in Taiwan in
1989), the disturbing thing, even for someone who has lived in earthquake
zones for years, is the aftershocks. They build up to a doubt about whether
the earth can ever be counted on to lie still. Now after more than a decade of
living somewhere where earthquakes are unknown, I largely am back to counting
on the earth beneath my feet to lie still. (The danger here, and it is a
considerable danger, is slipping and falling on ice. That paralyzed my dad for
the last six years of his life.) The earthquake news from Japan brings back a
lot of memories from the Ring of Fire. Many people there will be wondering
over the next few weeks if the term "solid ground" has any meaning at all.

~~~
X-Istence
I lived in Phoenix when there was an Earthquake somewhere down south in Mexico
and I felt it. The earth was moving back and forth, the blinds on my window
moved back and forth and not ever having felt an Earthquake it was the
weirdest feeling in the world.

I can't imagine a strong earthquake or what it would feel like, but Phoenix
which is definitely not known for its earthquakes moving underneath my feet
made me more wary about what I am walking on than ever before.

~~~
gnaritas
When was this? I've been in Phoenix for 20 years have never heard of anyone
here saying such a thing.

~~~
X-Istence
Last year, sometime around April if I remember correctly... let me check my
Facebook backup. (Yay for searching a big huge HTML document)

April 4, 2010 is when it happened, sometime late in the morning, afternoon. I
just remember just waking up and trying to decide if I should go take a shower
or not, and thus lying in bed.

[http://earthquake.usgs.gov/earthquakes/eqarchives/poster/201...](http://earthquake.usgs.gov/earthquakes/eqarchives/poster/2010/20100404.php)

[http://www.examiner.com/supernatural-christianity-in-
phoenix...](http://www.examiner.com/supernatural-christianity-in-
phoenix/phoenix-area-feels-easter-sunday-earthquake)

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jevinskie
Does this affect the orbit of satellites? Do satellite location services like
GPS need recalibration?

~~~
jerf
It will not greatly affect the orbit of any satellite, because the Earth's
center of gravity can't be shifted by any action internal to the Earth itself
by conservation of momentum, excepting somehow raising some part of Earth
above the relevant orbits which no earthquake is going to do. Otherwise to
change the trajectory of Earth's center of gravity requires an external force
of some sort. Some small effect from a different mass distribution will be
caused and it will have to be taken into effect, but when you care about these
effects as far as I know you have to measure them empirically anyhow, because
if you care at that level of detail it turns out there's a lot of noise as the
Earth warms and cools and has various flows within it and as water moves
hither and yon and so on. So while it will have some effect it is merely one
of very many such things.

Technically speaking, it won't require any recalibration either, because when
the satellites tell you that you are 2.4 meters away from where you were
yesterday when standing in the "same location", _they're right_. (Assuming
this number is reliable.) GPS doesn't really tell you where you are "on the
surface", they tell you where you are within the sphere they encompass and
from there we map that back to the surface location with other knowledge our
systems have. If Madagascar took it upon itself to go dock with Australia
tomorrow, the GPS satellite system itself would not need to be updated. All
the things that _use_ GPS and have some reason to expect Madagascar to be in a
certain location would need to be updated.

~~~
Rexxar
> It will not greatly affect the orbit of any satellite, because the Earth's
> center of gravity can't be shifted ...

Even if the center of gravity is not moved, there is an impact on
trajectories. We are used to use a simplification that consider only the
gravity center (using this theorem
<http://en.wikipedia.org/wiki/Shell_theorem>) but this theorem doesn't apply
if we want to be really precise.

~~~
jerf
Is it the case that you might explain such a thing with words that look
something like "Some small effect from a different mass distribution will be
caused and it will have to be taken into effect, but when you care about these
effects as far as I know you have to measure them empirically anyhow, because
if you care at that level of detail it turns out there's a lot of noise as the
Earth warms and cools and has various flows within it and as water moves
hither and yon and so on. So while it will have some effect it is merely one
of very many such things."? If only I had thought to add such words to my
original post. Alas.

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silentbicycle
I've felt a distant earthquake once, in _Michigan_ (not exactly an earthquake
zone) - it was deeply unnerving, particularly in an office on the fifth floor
of an old factory building. I can't imagine being trapped amidst suddenly
collapsing buildings, or knowing that it could potentially happen any time. I
hope the worst is over and people have reconnecting with their families by
now.

Also, I don't want to trivialize what the Japanese are going through, but why
does Japan move in metric while the Earth moves in imperial units? Sheesh.

~~~
athom
How long ago was that? I felt one from Michigan myself a few years back, that
originated down in southern Indiana. That was around 3 or 4AM, though, so
unless you were working late or living in your office...

The American midwest may not be earthquake central, but it has its faults. New
Madrid, in particular:

<http://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone>

I remember the noise around Iben Browning's 1989/90 prediction, but it looks
like nothing major has happened there since. Yet.

~~~
silentbicycle
It was this one, last June:
<http://en.wikipedia.org/wiki/2010_Central_Canada_earthquake> .

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seigenblues
somewhere in Japan, someone has hardcoded GPS locations into their autonomous
dishwashing robot, and is now wondering why it can't find the sink...

(btw, another version of the story with citations, attributed quotes is here:
[http://edition.cnn.com/2011/WORLD/asiapcf/03/12/japan.earthq...](http://edition.cnn.com/2011/WORLD/asiapcf/03/12/japan.earthquake.tsunami.earth/index.html))

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angus77
Now, isn't that _so_ Canadian? The headline mixes metric _and_ imperial.

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hysterix
The power of the northridge earthquake was indescribable. To think that this
quake in Japan was more powerful blows me away. During the northridge quake,
it literally felt like the entire world was coming to an end.

~~~
Bud
The Japan quake (8.9) was over 900 times more powerful than Northridge (6.7).

Each point on the Richter scale is a 30x increase in energy.

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Pyrodogg
Contains some bullet points with nothing to back them or the headline up. Has
some videos though if you haven't caught them elsewhere.

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spoiledtechie
The U.S. military is planning an excursion and training exercise later this
year on the Madrid Fault. My company is planning on demoing some new tech
there. <http://pubs.usgs.gov/fs/2003/fs017-03/images/madrid.jpg>.

Last time it hit, the bells range in Massachusetts around 1890. If one were to
hit today expected loss of life is in the 1000's. They would expect a total
loss of infrastructure for stuff that has been built over 100 years ago. They
have no earthquake building codes so imagine something that would destroy
buildings just like the one did in Japan. Happily only several hundred were
lost compared to what is expect of the Madrid fault.

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arrogant
I live in Florida, and I'll take the risk of hurricanes and tornadoes any day
over earthquakes. Just the sudden and unavoidable nature of earthquakes makes
them seem orders of magnitude worse to me.

~~~
codex
How do you feel about the risk that most of Florida will be underwater in a
few decades?

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arrogant
Let the whole state go under. I'll be long gone by then. (All kidding aside, I
haven't really heard anything about that, and it isn't a pleasant thought. Any
particular articles on the subject that you've seen?)

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codex
I'm only half-joking. The sealevel rise estimates are all over the map (no pun
intended). For one estimation on the effect on Florida, see:
[http://www.globalwarmingart.com/sealevel?lat=30.487&lng=...](http://www.globalwarmingart.com/sealevel?lat=30.487&lng=-84.375&zoom=5)

For one estimate of +2m, see: [http://www.reportingclimatescience.com/news-
stories/article/...](http://www.reportingclimatescience.com/news-
stories/article/global-warming-may-cause-2m-sea-level-rise-this-century-say-
experts.html)

Again, I don't know how likely this is, but Florida is one of the most
vulnerable states in the US. The prize probably goes to Louisiana with North
Carolina in the top 3.

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maayank
a. does it mean that the velocity of earth's rotation changed? b. and thus, by
virtue of relativity, time (for us earth people)?

~~~
brazzy
If the rotation speed of earth changed (and this is definitely possible), then
by a really, really tiny amount (something like a day getting a thousandth of
a second longer or shorter)

