
7.1 magnitude earthquake hits Japan - ssclafani
http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc0002ksa.php
======
powertower
A 7.1 is 1.5 megatons of TNT Seismic Energy Yield.

A 9.2 is 2.5 gigatons.

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whyenot
The 6.9 Loma Prieta earthquake killed 63 people and left thousands homeless in
California in 1989.

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TomOfTTB
What made that quake significant was the duration (it went on for 15 seconds).
That's a factor that supersedes the strength of the quake to an extent.
Because a weaker quake will cause more damage over a long period of time.

Put it this way: Hit a wall with a hammer and you might cause a dent.
Continually hit that wall with a hammer for 15 seconds and you'll probably
break through.

~~~
lappet
The 2001 earthquake in Gujarat lasted for more than 2 minutes and killed
around 20,000 people. The quake struck early in the morning during India's
Republic day celebrations. The authorities said that the long duration caused
more damage <http://en.wikipedia.org/wiki/2001_Gujarat_earthquake>

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wiredfool
I wish I could downvote this as -1, duplicate.

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raganwald
Mentioning it's a duplicate is good, thank you. Next time this happens, a link
to the original post would be very helpful.

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flyosity
He meant as a duplicate of the earthquake that already devastated Japan. He
wished he could downvote it as a duplicate, that is, that it hadn't happened
again.

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michaelty
Hope all the HNers in Japan are safe.

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jonny_eh
I hope everyone else is safe too.

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ozziegooen
I appreciate that comment, but don't like how many up-votes it got. From my
experience with Hacker News, the comments with the highest rankings are
usually those that point out another post as stupid, instead of those that
give valid information.

~~~
quacker
Nothing "stupid" was pointed out. It's a perfectly reasonable correction,
although the original poster probably only phrased it that way since only
"HNers" would see his post.

And I know what you mean, but I hope you at least realize the inherent
hypocrisy in making a post only to complain about posts not yielding valid
information.

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nickolai
Page has been updated to 7.1

(EDIT : I see you updated the title. Also always good to see an earthquake
magnitude overestimated)

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z92
So what was the magnitude before being corrected?

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noodle
7.4

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acconrad
Here's (unfortunately) another reminder to donate to the relief fund via
RedCross:
[https://american.redcross.org/site/Donation2?5052.donation=f...](https://american.redcross.org/site/Donation2?5052.donation=form1&df_id=5052&idb=0)

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natural219
Sorry if I'm being insensitive, but is this big news? I didn't think 7.1 was
that powerful.

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geoffw8
Nah, 7.1 is pretty big.

Its especially big news when you consider the events of the last 30 days.

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antirez
Yep, Messina, Sicily, and the tsunami caused a lot of deaths in that case if I
remember correctly. Btw full details here ->
<http://en.wikipedia.org/wiki/1908_Messina_earthquake>

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aphexairlines
Parts of Iwate lost power?
<http://twitter.com/#!/daiwaka/status/56008913857949696>

~~~
electromagnetic
Likely they did, but probably no more than would have happened anywhere in
high-winds.

I know here in the Greater Toronto Area can get hit by blackouts frequently
because of tree falls. Having moved here from the UK I don't get the idiotic
notion of letting trees grow through your power lines because inevitably a
branch or the whole tree will fall and knock out power. I've seen a few trees
that are so big that no matter what way they fall, they'll knock out power to
both sides of the street.

It's surely caused by the earthquake, but it's hard to tell if it would only
be cause by the earthquake. You've got to draw a line between "act of god" and
an "act of man" for being stupid enough to let an earthquake, windstorm or
snowstorm knock your power out.

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shawnee_
Holy cow, this is an active day for semi-large earthquakes all over the
planet:

    
    
      7.1 2011/04/07 14:32:42 NEAR THE EAST COAST OF HONSHU, JAPAN
      5.8  	2011/04/07 20:41:54  NORTH OF HONDURAS
      6.5  	2011/04/07 13:11:25  VERACRUZ, MEXICO
      

source: <http://quakes.globalincidentmap.com/>

~~~
ars
There are earthquakes of magnitude 6 or larger quite often, probably every
week. And under 6 (like the 5.8) are even more common.

~~~
shawnee_
_There are earthquakes of magnitude 6 or larger quite often, probably every
week. And under 6 (like the 5.8) are even more common._

I'll hold my assertion that it seems to be a more active week than normal in
the seismological world.

Your comment adds nothing here and is not backed up by any evidence; "probably
every week" does not count as evidence. The majority of the number that the
USGS counts includes quakes below the ocean.
[http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqsta...](http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php)

The USGS calls anything 6+ "large". A magnitude 6 earthquake can be deadly.
Even magnitude 5 < can be deadly. There are factors at work depth of the quake
as well as other factors, like location where it hits.

[http://en.wikipedia.org/wiki/List_of_deadly_earthquakes_sinc...](http://en.wikipedia.org/wiki/List_of_deadly_earthquakes_since_1900)

~~~
ars
Did you really say "not backed up by any evidence", and in the very next
sentence provide the actual evidence??

If you look at that handy evidence you provided: Magnitude 6 or larger quakes
happen 150 times a year. That's about 2 or 3 a week.

And regarding 5.8 magnitude one you mentioned: earthquakes in that range
happen about 10 times a day!

Are you really surprised that events that occur this often happen to cluster
up on one day?

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orblivion
Is this just an aftershock?

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bluedanieru
I'd hesitate to say 'just', and there is a rigorous definition of aftershock
that this may or may not fit, but it's very close to the big one last month
and certainly related to it.

So I'd go with 'yeah, basically' in the absence of a seismologist telling me
otherwise.

~~~
rbonvall
In January there was a 6.9 quake here in Chile, and seismologists said it was
an aftershock of the big earthquake of one year earlier. For what I recall,
any earthquakes within a couple of years of the big one are most probably
aftershocks.

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harshpotatoes
So, this brings the number of >6.5 mag earthquakes off the cost of japan in
the past month up to like 12 I believe?*

Surely there is a geologist in the midst who can explain whether this is
normal/expected?

*<http://neic.usgs.gov/neis/qed/>

~~~
pchristensen
IANAG but IIRC quakes often happen in bunches like this as the earth's crust
settles into a semi-stable state.

~~~
harshpotatoes
Yeah. I guess. And doing some more looking on the internet and possibly
answering my own question, maybe:
<http://en.wikipedia.org/wiki/Earthquake_swarm>

It's hard to find useful information on line about this. But I guess that the
lack of information in itself probably means that geologists aren't
particularly worried about it.

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aphexairlines
Saw some posts on twitter that nhk switched to a documentary about cranes
about 40mins ago, but channel 1 here was still showing coverage until a couple
minutes ago. Don't people mean NHK G when they mention NHK?

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rodmiranda13
Will radioactive water be spread?

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JshWright
Tsunamis (and waves in general) don't actually move the water they're
traveling through over any significant distance. It's the wave's energy that's
moving, not the water itself.

~~~
5h
this is only true until the sea meets land.

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phlux
Exactly. The water level is raised, and then water "falls" along the path of
least resistance, in the case of shore - it will certainly flow onto land.

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aphexairlines
english feed: [http://twitter.com/#!/list/TheTokyoPost/japan-earthquake-
cov...](http://twitter.com/#!/list/TheTokyoPost/japan-earthquake-coverage)

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dami
Very sad news, I hope everyone there is safe.

~~~
Tichy
I think this was probably a "normal" earthquake which Japan is built to
withstand without many problems.

~~~
allwein
True, but I imagine that Japanese infrastructure may have been compromised by
the earlier earthquake, making this one more dangerous than it would be
otherwise.

Much like the Flu is usually no big deal, but can easily kill people with any
sort of immuno-deficiency.

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iM8t
Any live stream up already?

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bluedanieru
There was some pretty strong shaking in Tokyo, warning of tsunami up to 2m in
Miyagi, 1m elsewhere along the east coast down to Chiba. The tsunami will have
arrived in Miyagi by now.

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mkramlich
I've flagged this for being off-topic for HN. Hopefully others will join me.

~~~
bad_user
There's offtopic and then there's offtopic.

I think this one is OK -- and personally if I see another article about how
awesome or evil or dickish (or whatever) Facebook/Twitter/Microsoft/Google
are, or about how shitty News Corp handled Myspace, or simply showbiz/yellow
journalism junk (i.e. pictures of Jobs meeting with Schmidt) I think I'm going
to puke.

But there's lots of offtopic articles (i.e. not related to startups or
hacking) everyday -- complaining about it just adds more noise and is
completely pointless.

~~~
mkramlich
I didn't complain. Simply took action to help fight noise and hoped to rally
others to do the same. I consider a report of Yet Another Earthquake in Japan
to be off-topic. We have mainstream news sources for that. And if it's truly
important, that sort of news will find us. Through other channels.

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steevdave
How is this pertinent to HN but the Israel attacks on Gaza not?

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nyellin
An earthquake in Japan is not controversial and might have business
implications for some people on HN.

Edit: Removed pro-Israel defense. This is not the place for a political
discussion.

~~~
HelloBeautiful
>> This is not the place for a political discussion.

Your post is still politically loaded. Israel attacks on Gaza are as
'controversial' as evolution, global warming and tobacco causing cancer.

~~~
nir
It is controversial when you define it "Israel attacks on Gaza". The attacks
go both ways - eg, Hamas rocket hit an Israeli school bus this morning.

(This stuff might have had a place here once, but as it is now the HN thread
won't be any more intelligent than the Reddit one)

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HelloBeautiful
The pro-Israel online lobby is soooo annoying ...

Lets move the discution to the definition of some word. Lets call everyone
with a different opinion stupid. Lets put out your opinion and try to close
the thread ...

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nir
See?

~~~
HelloBeautiful
No.

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aphexairlines
This sucks. Earthquakes used to be interesting but now when that alert goes
off on phones + tv and the shockwave hits it's internal panic time.

