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View Full Version : Gravitational pull 'has role in quakes'? How mainstream is this journal?



LookingSkyward
2016-Sep-13, 05:09 PM
I seem to recall seeing this discussed here on the forums before, and I am not advocating any position.
My question is 'How mainstream is this journal'? That is, is this a generally respected journal, or more sketchy?


from the news article:
"The gravitational forces responsible for high tides may also play a role in triggering major earthquakes, a study suggests.

The researchers led by Satoshi Ide, from the University of Tokyo, have published their findings in the journal Nature Geoscience."


Link to the news article:
http://www.bbc.com/news/science-environment-37350839

WaxRubiks
2016-Sep-13, 05:19 PM
I think I read the Earth's surface rises and falls each day..a meter or so, I can't remember.....that might put some pressure on faults, some think.

CJSF
2016-Sep-13, 06:48 PM
It's fairly mainstream, from what I've seen cross my Twitter feed (from bonafide geoscientists). But the meat of the paper puts constraints on how much influence it has, and there's nothing really unexpected about it. The tidal strain on the crust may "tip" a fault into action, given other factors, but any predictive power is low.

CJSF

grapes
2016-Sep-13, 06:53 PM
I seem to recall seeing this discussed here on the forums before, and I am not advocating any position.
My question is 'How mainstream is this journal'? That is, is this a generally respected journal, or more sketchy?


from the news article:
"The gravitational forces responsible for high tides may also play a role in triggering major earthquakes, a study suggests.

The researchers led by Satoshi Ide, from the University of Tokyo, have published their findings in the journal Nature Geoscience."


Link to the news article:
http://www.bbc.com/news/science-environment-37350839
It's Nature Geoscience, of Nature, one of the most respected journals.

In general, studies have seldom shown any correlation between earthquakes and seismicity. I'll take some time and read the article: http://www.nature.com/articles/ngeo2796.epdf

ETA: Weird. When I click on that link, I get a copy of the article that has the 2nd and following pages obscured. When I click on the link in LookingSkyward's article, I seem to be able to read the entire thing. Pay sites...

EETA: And even then, the "Methods" portion of the article seems to be behind the pay wall.

Squink
2016-Sep-14, 02:46 PM
Earth tide (https://en.wikipedia.org/wiki/Earth_tide)
Its main component has meter-level amplitude at periods of about 12 hours and longer.
Tidal triggering of earthquakes (https://en.wikipedia.org/wiki/Tidal_triggering_of_earthquakes) has refs back to the 60's. I was taught about the effect in Geology 101 back in the mid 70's.

CJSF
2016-Sep-14, 05:48 PM
The effect has long been theorized, but it's my understanding that this is the first research that actually shows it and characterizes it.

CJSF

grapes
2016-Sep-14, 06:33 PM
Earth tide (https://en.wikipedia.org/wiki/Earth_tide)
Tidal triggering of earthquakes (https://en.wikipedia.org/wiki/Tidal_triggering_of_earthquakes) has refs back to the 60's. I was taught about the effect in Geology 101 back in the mid 70's.
Yahbut, the small correlations found don't seem useful in predicting earthquakes. For instance, any region with a tidal-stress-induced earthquake has probably experienced very nearly the same stress just a half day earlier.

WaxRubiks
2016-Sep-14, 06:41 PM
earthquakes are perhaps like bombs with different length fuses.....so the thing that lights the fuse won't correlate very strongly with the earthquake.

01101001
2016-Sep-14, 10:47 PM
Somebody needs to mention Jim Berkland. There, I just did. Wikipedia: Jim Berkland (https://en.wikipedia.org/wiki/Jim_Berkland)


In 2006 Berkland's method was described as the "Three Double G" system: 1) "the gravity gradient, or the forces exacted on the earth by the gravitational pull of the Sun and the Moon." 2) "Gone Gatos" (missing cats) as indicated by advertisements in several newspapers. 3) "Geyser Gaps", seen as irregularities in the behavior of a geyser in the Napa Valley. Berkland's method has been said to also involve "a hodge-podge of factors".

There was a lot of pseudoscience to his methods and predictions. File under blind-pig acorn.

nota
2016-Sep-22, 08:38 PM
I think I read the Earth's surface rises and falls each day..a meter or so, I can't remember.....that might put some pressure on faults, some think.

NO
or GPS elevations would also vary by a meter daily
and as a land surveyor no level run would ever check flat
and they do NOT and are repeatable to 0.1 meter if not scrambled by GPS
and to under 0.001 by me on a survey level instrument

CJSF
2016-Sep-22, 09:16 PM
NO
or GPS elevations would also vary by a meter daily
and as a land surveyor no level run would ever check flat
and they do NOT and are repeatable to 0.1 meter if not scrambled by GPS
and to under 0.001 by me on a survey level instrument

https://en.wikipedia.org/wiki/Earth_tide

I know I know, it's Wikipedia. But it has references, and I remember learning about Earth tides in both undergrad and grad school Geography. I'm not sure how that jibes with surveying, but it seems to be a well studied and documented affect.

This seems interesting too:
http://onlinelibrary.wiley.com/doi/10.1002/jgrb.50159/abstract

CJSF

WaxRubiks
2016-Sep-22, 09:21 PM
the meter high bulge is spread over thousands of miles, so I don't think it would really affect surveying, and the flatness of the land...?

nota
2016-Sep-24, 08:07 PM
the meter high bulge is spread over thousands of miles, so I don't think it would really affect surveying, and the flatness of the land...?

on the level run no if the starting and ending bench marks both move an equal amount
but doing stuff takes time and 1 meter per 12 + hours is a LOT of movement
I have done level runs taking 6 hours to complete a circuit withOUT seeing any such effect
on GPS yes it would be eazy to see
as GPS level is measured directly from the sat to the ground surface at that instant
and NO I have never seen near that much change

level runs over 0.03 of a foot of error = about 0.01 meter are rejected and redone

WaxRubiks
2016-Sep-24, 08:09 PM
on the level run no if the starting and ending bench marks both move an equal amount
but doing stuff takes time and 1 meter per 12 + hours is a LOT of movement
I have done level runs taking 6 hours to complete a circuit withOUT seeing any such effect
on GPS yes it would be eazy to see
as GPS level is measured directly from the sat to the ground surface at that instant
and NO I have never seen near that much change

level runs over 0.03 of a foot of error = about 0.01 meter are rejected and redone


maybe the sat system adjusts for it? I don't know.

WaxRubiks
2016-Sep-24, 08:39 PM
21774
https://forum.cosmoquest.org/attachment.php?attachmentid=21774&d=1474749573
https://books.google.co.uk/books?id=SBiJCgAAQBAJ&pg=PA527&lpg=PA527&dq=does+sat+nav+adjust+for+%22earth+tide%22&source=bl&ots=W5IP-tVeao&sig=y2des8MHzze2epiSMLBr0iiVzpY&hl=en&sa=X&ved=0ahUKEwiS-Lzs7KjPAhXKAcAKHeiSDVoQ6AEIKDAC#v=onepage&q=does%20sat%20nav%20adjust%20for%20%22earth%20tid e%22&f=false

nota
2016-Sep-24, 08:55 PM
from your link

''based on our error assessments, we assert that the accuracy in our GPS displacement estimates is better than 0.12 mm (horizontal) and 0.24 mm (vertical) for the lunar-only constituents (M2, N2, O1 and Q1), at 0.69 mm (horizontal) and 1.29 mm (vertical) for S2 and P1, and somewhat poorer for K2 and K1 due to inherent errors in satellite orbit modeling and multipath effects. We note that ambiguity resolution in the GPS data processing improves the precision, especially for the four solar-related constituents, S2, K2, K1, and P1.''
I am unsure if the 0.24mm lunar is added to the 1.29 mm (vertical) for S2 and P1, solar max values
but total movement is under 2mm in that case NOT 1m as sited in the post I disputed for land crust movements
and that value should not effect a survey level run unlike a 1m max change value sited

WaxRubiks
2016-Sep-24, 08:59 PM
I presume some more accurate satnavs will adjust for that 1meter vertical tide...ie the earth surface will rise and fall by half a meter and the satnav will adjust so that the reading will stay the same, for the same coordinates.

slang
2016-Sep-27, 07:54 PM
There was a thread on tides and earthquakes (https://forum.cosmoquest.org/showthread.php?113846-Earthquakes-more-common-at-high-tide) in Q&A a few years ago. If the BBC article is an accurate description of the research I find it peculiar that they do find a correlation for large quakes, but not small ones. Especially if earlier studies did find some correlation for smaller quakes of certain types.