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big-will

The general 'Japan earthquake' topic

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Not really - earthquakes can't be predicted as to where and when they will occur, only the general vicinity of where one may occur.

 

Earthquakes can occur anywhere between the Earth's surface and about 700 kilometers below the surface. For scientific purposes, this earthquake depth range of 0 - 700 km is divided into three zones: shallow, intermediate, and deep.

Shallow earthquakes are between 0 and 70 km deep; intermediate earthquakes, 70 - 300 km deep; and deep earthquakes, 300 - 700 km deep. In general, the term "deep-focus earthquakes" is applied to earthquakes deeper than 70 km. All earthquakes deeper than 70 km are localized within great slabs of shallow lithosphere that are sinking into the Earth's mantle.

The evidence for deep-focus earthquakes was discovered in 1922 by H.H. Turner of Oxford, England. Previously, all earthquakes were considered to have shallow focal depths. The existence of deep-focus earthquakes was confirmed in 1931 from studies of the seismograms of several earthquakes, which in turn led to the construction of travel-time curves for intermediate and deep earthquakes.

The most obvious indication on a seismogram that a large earthquake has a deep focus is the small amplitude, or height, of the recorded surface waves and the uncomplicated character of the P and S waves. Although the surface-wave pattern does generally indicate that an earthquake is either shallow or may have some depth, the most accurate method of determining the focal depth of an earthquake is to read a depth phase recorded on the seismogram. The depth phase is the characteristic phase pP-a P wave reflected from the surface of the Earth at a point relatively near the hypocenter. At distant seismograph stations, the pP follows the P wave by a time interval that changes slowly with distance but rapidly with depth. This time interval, pP-P (pP minus P), is used to compute depth-of-focus tables. Using the time difference of pP-P as read from the seismogram and the distance between the epicenter and the seismograph station, the depth of the earthquake can be determined from published travel-time curves or depth tables.

Another seismic wave used to determine focal depth is the sP phase - an S wave reflected as a P wave from the Earth's surface at a point near the epicenter. This wave is recorded after the pP by about one-half of the pP-P time interval. The depth of an earthquake can be determined from the sP phase in the same manner as the pP phase by using the appropriate travel-time curves or depth tables for sP.

If the pP and sP waves can be identified on the seismogram, an accurate focal depth can be determined.

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Do you guys like having that earthquake warning thing on your phones switched to On or Off?

 

I would rather not know. Those TV warnings that come up get my heartbeat pumping, I'm not sure I want to know!

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I would rather know, but sometimes there isn't much point to it as it may only come a second before.

Heck, sometimes comes after...

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I have mine on, but they don't always come before the quake and sometimes they don't come at all! I do have it set for just the bigger quakes!

When you hear the sound it is a bit disturbing though!

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I reckon I wouldbe thankful for even 5 seconds warning... You may be about to do something or in the middle of something super dangerous and be able to alter an outcome. Even just enough time to grab a child so they are with you if things start going badly would be appreciated.

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Sounds good, but in the actual situation I have found myself pretty much always just standing up, frozen, crapping myself and really not actually being able to do much.

I can see how it is good if you are doing things like cooking on the stove etc or as you say with children, yes.

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Sounds good, but in the actual situation I have found myself pretty much always just standing up, frozen, crapping myself and really not actually being able to do much.

I can see how it is good if you are doing things like cooking on the stove etc or as you say with children, yes.

 

Most gas devices now turn off automatically when an earthquake happens. And with kids, they are taught from a very young age, to dive under tables. So much so, that when I used to teach at a kindergarten, they would leave me for dust as soon as the building started shaking.

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My card is a 4 pin card......I've never heard of 6-pin ATM cards.

 

Yeah MiJ, my mates heating turned off after the quake on Saturday.....it took him a while to realise why he was so cold :lol:

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Do you guys like having that earthquake warning thing on your phones switched to On or Off?

 

I would rather not know. Those TV warnings that come up get my heartbeat pumping, I'm not sure I want to know!

 

I don't have that on my phone. My feeling is that if it is anything to worry about, you'll know soon enough. And the warnings are wrong more then 50% of the time.

 

On 3.11 the alarms on everybody else's phones were going off like crazy after the main event, making me wonder if that no-s$%&-Sherlock uselessness was contributing to eating up all the bandwidth and preventing useful phone calls from getting through.

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Lots of the news programs last night had that earthquake news on and discussing the "70% within 4 years" thing.

 

I know nothing about the science, but makes you wonder how much they would let on if some real signs of something big coming happened (?)

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There's a fair bit of concern being expressed down here on the Izu penninsula. But then again, there always has been.

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There's a fair bit of concern being expressed down here on the Izu penninsula. But then again, there always has been.

 

 

It'll probably break off and become it's own country. ;)

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70% is more than twice as likely to happen as not happen :veryshocked:

 

Let's hope AC are working on some better adverts.The last ones were SHITE! ;)

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There sure are a lot of "lets get scared" stories at the moment.

 

Here's another from today

 

東日本大震災の地震発生がきっかけになり、東北地方沖の太平洋プレートの深い部分で、岩盤同士が押し合っていた力が、引っ張り合う力に転じていたことを、海洋研究開発機構などの研究グループが突き止めた。

l1x1-0d3a1fb758df89fe76286575fa2fbffc9ae83d03.gif

 引っ張る力がプレート内でより強く働くようになり、マグニチュード(M)8・1の昭和三陸地震と同じタイプの大規模地震が起きやすくなっていることを示す成果。31日付の米物理学会誌に掲載される。

 東日本大震災の本震は陸側のプレートの下に、太平洋プレートが沈み込む「プレート境界」で起きた。この太平洋プレートの浅い部分では岩盤を引っ張る力、深い部分では押し合う力が働いているが、巨大地震の発生で、このバランスがどう変わったかはわかっていなかった。

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The same in native English:

 

Earthquake occurrence of east Japanese large earthquake disaster becomes opportunity, in the part where the Pacific Ocean plate of the northeast local open sea is deep, the power where the base rock has jostled, the fact that it changed to the power to pull was pinpointed, the research group of oceanic research and development mechanism and the like.  The result which shows the fact that it reaches the point where the power which pulls works more strongly inside the plate, magnitude (M) large-scale earthquake of the same type as 8.1 Showa Aomori, Iwate, and Miyagi Prefectures earthquakes to occur it becomes easy. It is published to the American physics periodical of 31 dates.  Main shock of east Japanese large earthquake disaster the Pacific Ocean plate sinks under the plate of shore and, is packed it occurred with “plate boundary”. In the part where this Pacific Ocean plate is shallow the power which pulls the base rock, in the deep part the power which jostles works, but you did not know with occurrence of enormous earthquake, this balance how changed.

 

;)

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According to the Japan TImes' style guide, that should read "enormous tremblor" at the end. Other than that, its ready for the presses!

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What I think that is all about is that they are saying now that there's 'a chance' of a M8 aftershock.

It'll probs be on the tv news tonight.

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What I think that is all about is that they are saying now that there's 'a chance' of a M8 aftershock.

It'll probs be on the tv news tonight.

 

And so it was. M8 more likely now due to Pacific Plate surface that was in compression before 3.11 now being pulled apart. Which could create a large tsunami, but since the epicenter would be further from land, it may only be a shindo 5 or less on land, so people may not take the tsunami risk seriously.

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Let's hope AC are working on some better adverts.The last ones were SHITE! ;)

 

if the people involved in making the AC adverts after a crazy disaster are reading, then I request, hot naked young ladies gratuitously showing their wares on the screen......no A-SHEEEEEE jingle, if you have to have music then some 70's soft porn music would add comedy value and set everyone at ease. When you constantly played those shite ads, I wanted to rip my face off and kill someone

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How many of us here have some sort of preparation going on?

 

Like a few torches around the house, some food or pack near the genkan in case an escape is needed etc?

 

I have the torches going on. I have a few of my cupboards attached to walls as well.

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I have some torches around the house, some candles, and some supplies in a bag in the genkan. I think they call it a 'grab-bag'.

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