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# Earthquakes

edited September 2017

Here's a preview of a new book on earthquakes and earthquake prediction:

«1

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1.
edited September 2017

And this is a good survey paper on tsunami detection and how it relates to tidal prediction.

S. Consoli, D. R. Recupero, and V. Zavarella, “A survey on tidal analysis and forecasting methods for Tsunami detection,” J. Tsunami Soc. Int. 33 (1), 1–56.

The question is whether we can one use knowledge of tides to deconvolute a tsunami signal from the underlying tidal signal.

This paper cites the one above

Percival, Donald B., et al. "Detiding DART® buoy data for real-time extraction of source coefficients for operational tsunami forecasting." Pure and Applied Geophysics 172.6 (2015): 1653-1678.

This is what the raw buoy signal looks like, with the tsunami at the end:

After removing the tidal signals, the isolated tsunami impulse response (due to the 2011 Japan quake) looks like:

Comment Source:And this is a good survey paper on tsunami detection and how it relates to tidal prediction. S. Consoli, D. R. Recupero, and V. Zavarella, [“A survey on tidal analysis and forecasting methods for Tsunami detection,”](https://t.co/99oJArTzdo) J. Tsunami Soc. Int. 33 (1), 1–56. The question is whether we can one use knowledge of tides to deconvolute a tsunami signal from the underlying tidal signal. This paper cites the one above Percival, Donald B., et al. ["Detiding DART® buoy data for real-time extraction of source coefficients for operational tsunami forecasting."](https://arxiv.org/pdf/1403.0528) Pure and Applied Geophysics 172.6 (2015): 1653-1678. This is what the raw buoy signal looks like, with the tsunami at the end: ![](http://imageshack.com/a/img923/8262/HxJK3w.png) After removing the tidal signals, the isolated tsunami impulse response (due to the 2011 Japan quake) looks like: ![](http://imageshack.com/a/img924/2434/knQssD.png) 
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2.

The above analysis was done with 6 constituent tidal parameters.

I have a home grown spreadsheet that uses a solver plugin that can fit to these tidal patterns.

This is one I did on the same waveform (after digitizing the plot) with 4 major tidal parameters and 4 minor parameters:

The yellow region is training which reached almost a 0.99 correlation coefficient, with the validation region reaching 0.92

This is the complex Fourier spectrum:

I've been wanting to try this for awhile -- to see if the solver setup that I've been using for fitting to ENSO would work for conventional tidal analysis.

Sure enough, if you give it the recommended tidal parameters, the solver will grind away and eventually find the best fitting amplitudes and phases for each parameter.

That's how easy it is to do tsumani detection from buoy data; have about 15 days worth of leading tidal buoy data and continuously update it, comparing it to a model and look for any discrepancies in the sea-level height.

Comment Source:The above analysis was done with 6 constituent tidal parameters. I have a home grown spreadsheet that uses a solver plugin that can fit to these tidal patterns. This is one I did on the same waveform (after digitizing the plot) with 4 major tidal parameters and 4 minor parameters: ![q](http://imageshack.com/a/img923/7308/kqLPyD.png) The yellow region is training which reached almost a 0.99 correlation coefficient, with the validation region reaching 0.92 This is the complex Fourier spectrum: ![qf](http://imageshack.com/a/img924/5681/95yDo3.png) I've been wanting to try this for awhile -- to see if the solver setup that I've been using for fitting to ENSO would work for conventional tidal analysis. Sure enough, if you give it the recommended tidal parameters, the solver will grind away and eventually find the best fitting amplitudes and phases for each parameter. That's how easy it is to do tsumani detection from buoy data; have about 15 days worth of leading tidal buoy data and continuously update it, comparing it to a model and look for any discrepancies in the sea-level height. 
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3.

The wikipedia page gives references for the terms of the predictability debate.

https://en.m.wikipedia.org/wiki/Earthquake_prediction#1990:New_Madrid.2C_U.S..28Browning.29


"Despite the confident announcement four decades ago that seismology was "on the verge" of making reliable predictions,[247] there may yet be an underestimation of the difficulties. As early as 1978 it was reported that earthquake rupture might be complicated by "heterogeneous distribution of mechanical properties along the fault",[248] and in 1986 that geometrical irregularities in the fault surface "appear to exert major controls on the starting and stopping of ruptures".[249] Another study attributed significant differences in fault behavior to the maturity of the fault.[250] These kinds of complexities are not reflected in current prediction methods.[251]

Seismology may even yet lack an adequate grasp of its most central concept, elastic rebound theory. A simulation that explored assumptions regarding the distribution of slip found results "not in agreement with the classical view of the elastic rebound theory". (This was attributed to details of fault heterogeneity not accounted for in the theory.[252])

Earthquake prediction may be intrinsically impossible. It has been argued that the Earth is in a state of self-organized criticality "where any small earthquake has some probability of cascading into a large event".[253] It has also been argued on decision-theoretic grounds that "prediction of major earthquakes is, in any practical sense, impossible."[254]

That earthquake prediction might be intrinsically impossible has been strongly disputed[255] But the best disproof of impossibility – effective earthquake prediction – has yet to be demonstrated.[256]"

[253] Geller, Robert J.; Jackson, David D.; Kagan, Yan Y.; Mulargia, Francesco (14 March 1997), "Earthquakes Cannot Be Predicted", Science, 275 (5306): 1616, doi:10.1126/science.275.5306.1616.

[254] Matthews, Robert A. J. (December 1997), "Decision-theoretic limits on earthquake prediction", Geophysical Journal International, 131 (3): 526–529, Bibcode:1997GeoJI.131..526M, doi:10.1111/j.1365-246X.1997.tb06596.x.](http://web.csulb.edu/~rodrigue/quake/geller.html).

[255] Sykes, Lynn R.; Shaw, Bruce E.; Scholz, Christopher H. (1999), "Rethinking Earthquake Prediction" Pure and Applied Geophysics, 155 (2–4): 207–232, Bibcode:1999PApGe.155..207S, doi:10.1007/s000240050263.

[255] Evison, Frank (October 1999), "On the existence of earthquake precursors", Annali di Geofisica, 42 (5): 763–770.

Comment Source:The wikipedia page gives references for the terms of the predictability debate. https://en.m.wikipedia.org/wiki/Earthquake_prediction#1990:New_Madrid.2C_U.S..28Browning.29 "Despite the confident announcement four decades ago that seismology was "on the verge" of making reliable predictions,[247] there may yet be an underestimation of the difficulties. As early as 1978 it was reported that earthquake rupture might be complicated by "heterogeneous distribution of mechanical properties along the fault",[248] and in 1986 that geometrical irregularities in the fault surface "appear to exert major controls on the starting and stopping of ruptures".[249] Another study attributed significant differences in fault behavior to the maturity of the fault.[250] These kinds of complexities are not reflected in current prediction methods.[251] Seismology may even yet lack an adequate grasp of its most central concept, elastic rebound theory. A simulation that explored assumptions regarding the distribution of slip found results "not in agreement with the classical view of the elastic rebound theory". (This was attributed to details of fault heterogeneity not accounted for in the theory.[252]) Earthquake prediction may be intrinsically impossible. It has been argued that the Earth is in a state of self-organized criticality "where any small earthquake has some probability of cascading into a large event".[253] It has also been argued on decision-theoretic grounds that "prediction of major earthquakes is, in any practical sense, impossible."[254] That earthquake prediction might be intrinsically impossible has been strongly disputed[255] But the best disproof of impossibility – effective earthquake prediction – has yet to be demonstrated.[256]" I had to dig out working links to the refs. [253] Geller, Robert J.; Jackson, David D.; Kagan, Yan Y.; Mulargia, Francesco (14 March 1997), "Earthquakes Cannot Be Predicted", Science, 275 (5306): 1616, doi:10.1126/science.275.5306.1616. [254] Matthews, Robert A. J. (December 1997), "Decision-theoretic limits on earthquake prediction", Geophysical Journal International, 131 (3): 526–529, Bibcode:1997GeoJI.131..526M, doi:10.1111/j.1365-246X.1997.tb06596.x.](http://web.csulb.edu/~rodrigue/quake/geller.html). [255] Sykes, Lynn R.; Shaw, Bruce E.; Scholz, Christopher H. (1999), "Rethinking Earthquake Prediction" Pure and Applied Geophysics, 155 (2–4): 207–232, Bibcode:1999PApGe.155..207S, doi:10.1007/s000240050263. [255] Evison, Frank (October 1999), "On the existence of earthquake precursors", Annali di Geofisica, 42 (5): 763–770. 
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4.

I agree with the difficulty of predicting a single earthquake. But for an ensemble, the triggering point must be Boltzmann or Arrhenius-like with an associated activation energy. If a swept lunisolar forcing provides the extra delta in energy to trigger, that will be observed in the spatio-temporal statistics.

Comment Source:I agree with the difficulty of predicting a single earthquake. But for an ensemble, the triggering point must be Boltzmann or Arrhenius-like with an associated activation energy. If a swept lunisolar forcing provides the extra delta in energy to trigger, that will be observed in the spatio-temporal statistics. 
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5.

"TULSA, Okla. (AP) — Oklahoma's former lead seismologist says he felt pressured by a University of Oklahoma official to not link the state's surge in earthquakes to oil and gas production."

https://www.usnews.com/news/best-states/oklahoma/articles/2017-11-15/former-oklahoma-seismologist-testifies-in-earthquake-lawsuit

"Holland also detailed a meeting that allegedly took place with Boren and Harold Hamm, a billionaire oilman who has given millions of dollars to the university. Holland said he was called into Boren's office after he wrote the paper.

Holland said Boren "expressed to me that I had complete academic freedom, but that as part of being an employee of the state survey, I also have a need to listen to, you know, the people within the oil and gas industry."

Holland testified that Hamm told him "to be careful of the way in which I say things, that hydraulic fracturing is critical to the state's economy in Oklahoma, and that me publicly stating that earthquakes can be caused by hydraulic fracturing was — you know, could be misleading, and that he was nervous about the war on fossil fuels at the time."

Comment Source:> "TULSA, Okla. (AP) — Oklahoma's former lead seismologist says he felt pressured by a University of Oklahoma official to not link the state's surge in earthquakes to oil and gas production." https://www.usnews.com/news/best-states/oklahoma/articles/2017-11-15/former-oklahoma-seismologist-testifies-in-earthquake-lawsuit > "Holland also detailed a meeting that allegedly took place with Boren and Harold Hamm, a billionaire oilman who has given millions of dollars to the university. Holland said he was called into Boren's office after he wrote the paper. >Holland said Boren "expressed to me that I had complete academic freedom, but that as part of being an employee of the state survey, I also have a need to listen to, you know, the people within the oil and gas industry." >Holland testified that Hamm told him "to be careful of the way in which I say things, that hydraulic fracturing is critical to the state's economy in Oklahoma, and that me publicly stating that earthquakes can be caused by hydraulic fracturing was — you know, could be misleading, and that he was nervous about the war on fossil fuels at the time." 
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edited November 2017

BBC R4 'Inside Science' reports on a study from the University of Colorado which claims that the frequencies of magnitude >7M earthquakes goes up with reduction of equatorial dimension correlating with millisecond differences in LOD.

"What might the length of the day have to do with the likelihood of destructive earthquakes around the world? According to Professors Rebecca Bendick and Roger Bilham, there's a correlation between changes in the rate at which the Earth rotates and the incidence of earthquakes of Magnitude 7 and above. The rotation speed of the planet increases and decreases over periods of years and decades. From their research, the earth scientists say that there's an substantial increase in the number of powerful earthquakes around the world five years after the Earth attains a peak in its spin speed and enters a period of slow down. The difference in day length is tiny but it is enough, say the researchers, to trigger already stressed faults in the crust to move sooner than later."

Comment Source:BBC R4 'Inside Science' reports on a study from the University of Colorado which claims that the frequencies of magnitude >7M earthquakes goes up with reduction of equatorial dimension correlating with millisecond differences in LOD. "What might the length of the day have to do with the likelihood of destructive earthquakes around the world? According to Professors Rebecca Bendick and Roger Bilham, there's a correlation between changes in the rate at which the Earth rotates and the incidence of earthquakes of Magnitude 7 and above. The rotation speed of the planet increases and decreases over periods of years and decades. From their research, the earth scientists say that there's an substantial increase in the number of powerful earthquakes around the world five years after the Earth attains a peak in its spin speed and enters a period of slow down. The difference in day length is tiny but it is enough, say the researchers, to trigger already stressed faults in the crust to move sooner than later." * http://www.bbc.co.uk/programmes/b09drjmh
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7.

Interesting study. There are several timescales involved in LOD changes.

The shortest time-scale is directly related to diurnal and semidiurnal lunisolar tides. This one also impacts earthquakes as per the recent USGS and Japan research

The intermediate time-scale is empirically related to ENSO, but I think this transitively relates to lunar forcing, which is discussed over on the ENSO threads. In other words, lunar forces ENSO, which then contributes to the LOD changes.

The longest time-scale is most puzzling to me, as the change is so gradual, but is thought to be due to mantle changes:

Here they are on Chao's chart:

That long one is the focus of the program

Comment Source:Interesting study. There are several timescales involved in LOD changes. The shortest time-scale is directly related to diurnal and semidiurnal lunisolar tides. This one also impacts earthquakes as per the recent USGS and Japan research The intermediate time-scale is empirically related to ENSO, but I think this transitively relates to lunar forcing, which is discussed over on the ENSO threads. In other words, lunar forces ENSO, which then contributes to the LOD changes. The longest time-scale is most puzzling to me, as the change is so gradual, but is thought to be due to mantle changes: Here they are on Chao's chart: ![lod](https://i2.wp.com/imagizer.imageshack.us/a/img513/3263/ci3s.png) That long one is the focus of the program 
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8.

In the first alledged zoom out of this diagramm from a "Chao paper" (whatever you mean by that) the LOD changes in the range of 1 millisecond but in the first image in the range of 2 milliseconds.

Comment Source:In the first alledged zoom out of this diagramm from a "Chao paper" (whatever you mean by that) the LOD changes in the range of 1 millisecond but in the first image in the range of 2 milliseconds. 
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9.
edited November 2017

I disagree. The longer term LOD variation was removed in in the inset, thus reducing the fluctuation extremes from 2 to 1. This is the paper by Chao cited in the figure: http://ivs.nict.go.jp/mirror/publications/gm2004/chao/

Here is another from Chao, showing the wavelet decompostion of LOD signal

B. F. Chao, W. Chung, Z. Shih, and Y. Hsieh, “Earth’s rotation variations: a wavelet analysis,” Terra Nova, vol. 26, no. 4, pp. 260–264, 2014.

Comment Source:I disagree. The longer term LOD variation was removed in in the inset, thus reducing the fluctuation extremes from 2 to 1. This is the paper by Chao cited in the figure: http://ivs.nict.go.jp/mirror/publications/gm2004/chao/ Here is another from Chao, showing the wavelet decompostion of LOD signal ![wavelet](https://i2.wp.com/imageshack.com/a/img922/5931/dmd8IH.png) B. F. Chao, W. Chung, Z. Shih, and Y. Hsieh, “Earth’s rotation variations: a wavelet analysis,” Terra Nova, vol. 26, no. 4, pp. 260–264, 2014. 
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10.
edited November 2017

I disagree. The longer term LOD variation was removed in in the inset, thus reducing the fluctuation extremes from 2 to 1.

OK on the image you showed it is not indicated that something had been taken away, the diagram header (Excess Length-of-day (LOD)) is exactly the same for the top as for the middle panel.

In the paper you cited it is written:

One sees that the interannul LOD variation is mainly caused by the anomalous mass transport (mostly in the east-west wind field) of the Southern Oscillation in the tropical Pacific-Indian Ocean.

Here the author writes about interannual LOD but nothing indicates that data been taken away. It is in this paper: http://www.earth.sinica.edu.tw/~bfchao/publication/eng/2003-Chao-EOS-Geodesy is not just for static measurements any more.pdf

where it is finally written:

the blue curve is VLBI measurement, after removal of the seasonal terms due to mass transports of meteorological origin and tidal forces;

So it is rather the short-term data (the annual) that had been taken away). Anyways do you know where he has the long-term LOD data from? The figure 1 caption just says:

The blue curve is the entire ∆LOD data set that human kind ever acquired (the post-1960 densification of data resulted from the advent of the atomic clock);

There is currently a discussion on https://plus.google.com/+TimothyGowers0/posts/GNdRfNqcZw9 about a paper, where nobody seems to know were the long-term LOD is coming from.

Comment Source:> I disagree. The longer term LOD variation was removed in in the inset, thus reducing the fluctuation extremes from 2 to 1. OK on the image you showed it is not indicated that something had been taken away, the diagram header (Excess Length-of-day (LOD)) is exactly the same for the top as for the middle panel. In the paper you cited it is written: >One sees that the interannul LOD variation is mainly caused by the anomalous mass transport (mostly in the east-west wind field) of the Southern Oscillation in the tropical Pacific-Indian Ocean. Here the author writes about interannual LOD but nothing indicates that data been taken away. It is in this paper: http://www.earth.sinica.edu.tw/~bfchao/publication/eng/2003-Chao-EOS-Geodesy%20is%20not%20just%20for%20static%20measurements%20any%20more.pdf where it is finally written: >the blue curve is VLBI measurement, after removal of the seasonal terms due to mass transports of meteorological origin and tidal forces; So it is rather the short-term data (the annual) that had been taken away). Anyways do you know where he has the long-term LOD data from? The figure 1 caption just says: >The blue curve is the entire ∆LOD data set that human kind ever acquired (the post-1960 densification of data resulted from the advent of the atomic clock); There is currently a discussion on https://plus.google.com/+TimothyGowers0/posts/GNdRfNqcZw9 about a paper, where nobody seems to know were the long-term LOD is coming from.
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11.

The long-term LOD seems to be the big mystery, and it also aligns to temperature variations.

Dickey, J.O.; Marcus, S.L.; de Viron, O. Air temperature and anthropogenic forcing: Insights from the solid Earth. J. Clim. 2011, 24, 569–574. http://journals.ametsoc.org/doi/full/10.1175/2010JCLI3500.1

There are some long tidal periodicities that may match according to this paper http://www.mdpi.com/2225-1154/5/4/83

Comment Source:The long-term LOD seems to be the big mystery, and it also aligns to temperature variations. Dickey, J.O.; Marcus, S.L.; de Viron, O. Air temperature and anthropogenic forcing: Insights from the solid Earth. J. Clim. 2011, 24, 569–574. http://journals.ametsoc.org/doi/full/10.1175/2010JCLI3500.1 There are some long tidal periodicities that may match according to this paper http://www.mdpi.com/2225-1154/5/4/83 
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The LOD plots at IERS start in 1992: https://data.iers.org/plottool/publicv2/2dLine.php?reset=true

but I think they have measurements since around 1973/1974: https://datacenter.iers.org/eop/-/somos/5Rgv/plotname/7/FinalsAllIAU1980-LOD-BULA.jpg

I doubt that tidal observations are so precise that you may reconstruct the LOD in milliseconds. It seems that there are some historical records on lunar occlusions or maybe other celestial observations, which are eventually combined with reconstructions of the earth magnetic field, but this seems not easy at least here

"The evolution of the core-surface flow over the last seven thousands years" by I. Wardinski and M. Korte from 2008

it is written:

Recently, Dumberry and Bloxham [2006] sought time–dependent azimuthal flows from an archeomagnetic field model and compared the variations in the core angular momentum computed from these flow solutions to the observed variations deduced from records of historical solar and lunar eclipses [Stephenson and Morrison, 1995]. Their study shows that assumptions made to derive core angular momentum changes on a decadal timescale prove to be invalid for millennia.

Where I sofar didnt manage to find out at what place in history they started to count in seconds and then in milliseconds.

Comment Source: The LOD plots at IERS start in 1992: https://data.iers.org/plottool/publicv2/2dLine.php?reset=true but I think they have measurements since around 1973/1974: https://datacenter.iers.org/eop/-/somos/5Rgv/plotname/7/FinalsAllIAU1980-LOD-BULA.jpg I doubt that tidal observations are so precise that you may reconstruct the LOD in milliseconds. It seems that there are some historical records on lunar occlusions or maybe other celestial observations, which are eventually combined with reconstructions of the earth magnetic field, but this seems not easy at least here <a href="http://onlinelibrary.wiley.com/doi/10.1029/2007JB005024/pdf">"The evolution of the core-surface flow over the last seven thousands years"</a> by I. Wardinski and M. Korte from 2008 it is written: >Recently, Dumberry and Bloxham [2006] sought time–dependent azimuthal flows from an archeomagnetic field model and compared the variations in the core angular momentum computed from these flow solutions to the observed variations deduced from records of historical solar and lunar eclipses [Stephenson and Morrison, 1995]. Their study shows that assumptions made to derive core angular momentum changes on a decadal timescale prove to be invalid for millennia. Where I sofar didnt manage to find out at what place in history they started to count in seconds and then in milliseconds. 
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13.
edited February 2018

Here is a plot from Chao from that same paper showing the contribution of LOD from various spectral sources. These are all defined by a characteristic frequency:

Going from right to left

1. Semi-diurnal tides --> Tidal forcing
2. Diurnal tides --> Tidal forcing
3. Long-period tides --> Tidal forcing
4. 40-60 day oscillation --> (see below)
5. Semi-annual --> Solar + Tidal
6. Annual --> Solar + Tidal
7. Core --> ???
8. ENSO --> Tidal forcing
9. QBO --> Tidal forcing
10. Secular --> ???

As for the 40-60 day oscillation, I was looking at my ENSO model with high resolution SOI data, and it appears to pick up this variation, with likely a slightly different response function than the longer period >1 year cycles that ENSO is known for.

http://contextearth.com/2017/11/24/high-resolution-enso-modeling/

The greater point in all this is that the vast majority of LOD variations is due to the cyclic variation in the lunisolar forcing. All these other behaviors such as ENSO and QBO that contribute to LOD variations are transitively related to lunisolar forcing as well.

I actually don't know what would be so surprising about such a result, in that the forcing that is required to cause LOD changes likely comes from some external force, and there aren't that many forces to choose from.

The only contribution remaining are from core changes in the mantle of the earth. I suppose that the earth's highly viscous mantle (with a liquid outer core that is much less viscous than the mantle) spinning at the rate that it does could also undergo changes that are ultimately tied to lunisolar tidal forcing.

What's left are slight variations in the LOD due to earthquakes, which truly are noise, apart from the fact that even these are transitively related to triggering by lunar forcing.

Comment Source:Here is a plot from Chao from that same paper showing the contribution of LOD from various spectral sources. These are all defined by a characteristic frequency: ![chao](https://imageshack.com/a/img923/3199/VbBoZC.gif) Going from right to left 1. Semi-diurnal tides --> Tidal forcing 2. Diurnal tides --> Tidal forcing 3. Long-period tides --> Tidal forcing 4. 40-60 day oscillation --> (see below) 5. Semi-annual --> Solar + Tidal 6. Annual --> Solar + Tidal 7. Core --> ??? 8. ENSO --> Tidal forcing 9. QBO --> Tidal forcing 10. Secular --> ??? As for the 40-60 day oscillation, I was looking at my ENSO model with high resolution SOI data, and it appears to pick up this variation, with likely a slightly different response function than the longer period >1 year cycles that ENSO is known for. http://contextearth.com/2017/11/24/high-resolution-enso-modeling/ ![soi](https://i0.wp.com/imageshack.com/a/img923/7154/PPfcVP.png) The greater point in all this is that the vast majority of LOD variations is due to the cyclic variation in the lunisolar forcing. All these other behaviors such as ENSO and QBO that contribute to LOD variations are transitively related to lunisolar forcing as well. I actually don't know what would be so surprising about such a result, in that the forcing that is required to cause LOD changes likely comes from some external force, and there aren't that many forces to choose from. The only contribution remaining are from core changes in the mantle of the earth. I suppose that the earth's highly viscous mantle (with a liquid outer core that is much less viscous than the mantle) spinning at the rate that it does could also undergo changes that are ultimately tied to lunisolar tidal forcing. What's left are slight variations in the LOD due to earthquakes, which truly are noise, apart from the fact that even these are transitively related to triggering by lunar forcing. 
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14.

http://arxiv.org/abs/1711.09898

Initiation of Plate Tectonics on Exoplanets with Significant Tidal Stress

J. J. Zanazzi, Amaury Triaud (Submitted on 27 Nov 2017) Plate tectonics is a geophysical process currently unique to Earth, has an important role in regulating the Earth's climate, and may be better understood by identifying rocky planets outside our solar system with tectonic activity. The key criterion for whether or not plate tectonics may occur on a terrestrial planet is if the stress on a planet's lithosphere from mantle convection may overcome the lithosphere's yield stress. Although many rocky exoplanets closely orbiting their host stars have been detected, all studies to date of plate tectonics on exoplanets have neglected tidal stresses in the planet's lithosphere. Modeling a rocky exoplanet as a constant density, homogeneous, incompressible sphere, we show the tidal stress from the host star acting on close-in planets may become comparable to the stress on the lithosphere from mantle convection. We also show that tidal stresses from planet-planet interactions are unlikely to be significant for plate tectonics, but may be strong enough to trigger Earthquakes. Our work may imply planets orbiting close to their host stars are more likely to experience plate tectonics, with implications for exoplanetary geophysics and habitability. We produce a list of detected rocky exoplanets under the most intense stresses. Atmospheric and topographic observations may confirm our predictions in the near future. Investigations of planets with significant tidal stress can not only lead to observable parameters linked to the presence of active plate tectonics, but may also be used as a tool to test theories on the main driving force behind tectonic activity.

Comment Source:http://arxiv.org/abs/1711.09898 >Initiation of Plate Tectonics on Exoplanets with Significant Tidal Stress > >J. J. Zanazzi, Amaury Triaud >(Submitted on 27 Nov 2017) >Plate tectonics is a geophysical process currently unique to Earth, has an important role in regulating the Earth's climate, and may be better understood by identifying rocky planets outside our solar system with tectonic activity. The key criterion for whether or not plate tectonics may occur on a terrestrial planet is if the stress on a planet's lithosphere from mantle convection may overcome the lithosphere's yield stress. Although many rocky exoplanets closely orbiting their host stars have been detected, all studies to date of plate tectonics on exoplanets have neglected tidal stresses in the planet's lithosphere. Modeling a rocky exoplanet as a constant density, homogeneous, incompressible sphere, we show the tidal stress from the host star acting on close-in planets may become comparable to the stress on the lithosphere from mantle convection. We also show that tidal stresses from planet-planet interactions are unlikely to be significant for plate tectonics, but may be strong enough to trigger Earthquakes. Our work may imply planets orbiting close to their host stars are more likely to experience plate tectonics, with implications for exoplanetary geophysics and habitability. We produce a list of detected rocky exoplanets under the most intense stresses. Atmospheric and topographic observations may confirm our predictions in the near future. Investigations of planets with significant tidal stress can not only lead to observable parameters linked to the presence of active plate tectonics, but may also be used as a tool to test theories on the main driving force behind tectonic activity.
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15.

At this week's AGU meeting, at least one of the seismologists was aware of the tidal/earthquake connection and this is a paper that she told me to look into: “Abnormally Strong Daily-Cycle S1 Strain Tide: Observation and Physical Mechanism” — http://onlinelibrary.wiley.com/doi/10.1002/2017JB014383/full

"Tidal signals are analyzed in the Plate Boundary Observatory borehole strainmeters in western North America. While the extracted diurnal strain tidal constituents (except daily-cycle S1) respond to the tidal forces in similar proportion, the S1 strain tide exhibits an abnormally strong amplitude, reaching tens to hundreds times larger than theoretical prediction."

This is a paper that explains : "Influence of Tidal Forces on the Triggering of Seismic Events" -- https://link.springer.com/article/10.1007/s00024-017-1563-5

"Results of calculations prove that stress increases as a function of depth reaching a value around some kPa at the depth of 900–1500 km, well below the zone of deep earthquakes. At the depth of the overwhelming part of seismic energy accumulation (around 50 km) the stresses of lunisolar origin are only (0.0–1.0)·10^3 Pa. Despite the fact that these values are much smaller than the earthquake stress drops (1–30 MPa) (Kanamori in Annu Rev Earth Planet Sci 22:207–237, 1994) this does not exclude the possibility of an impact of tidal forces on outbreak of seismic events. Since the tidal potential and its derivatives are coordinate dependent and the zonal, tesseral and sectorial tides have different distributions from the surface down to the CMB, the lunisolar stress cannot influence the break-out of every seismological event in the same degree. The influencing lunisolar effect of the solid earth tides on earthquake occurrences is connected first of all with stress components acting parallel to the surface of the Earth. The influence of load tides is limited to the loaded area and its immediate vicinity."

So it is possible that the theory is undershooting what the evidence is showing in terms of strain needed to trigger an earthquake.

Comment Source:At this week's AGU meeting, at least one of the seismologists was aware of the tidal/earthquake connection and this is a paper that she told me to look into: “Abnormally Strong Daily-Cycle S1 Strain Tide: Observation and Physical Mechanism” — http://onlinelibrary.wiley.com/doi/10.1002/2017JB014383/full > "Tidal signals are analyzed in the Plate Boundary Observatory borehole strainmeters in western North America. While the extracted diurnal strain tidal constituents (except daily-cycle S1) respond to the tidal forces in similar proportion, the S1 strain tide exhibits an abnormally strong amplitude, **reaching tens to hundreds times larger than theoretical prediction.**" This is a paper that explains : "Influence of Tidal Forces on the Triggering of Seismic Events" -- https://link.springer.com/article/10.1007/s00024-017-1563-5 > "Results of calculations prove that stress increases as a function of depth reaching a value around some kPa at the depth of 900–1500 km, well below the zone of deep earthquakes. At the depth of the overwhelming part of seismic energy accumulation (around 50 km) the **stresses of lunisolar origin are only (0.0–1.0)·10^3 Pa**. Despite the fact that these values are much smaller than the earthquake stress drops (**1–30 MPa**) (Kanamori in Annu Rev Earth Planet Sci 22:207–237, 1994) this does not exclude the possibility of an impact of tidal forces on outbreak of seismic events. Since the tidal potential and its derivatives are coordinate dependent and the zonal, tesseral and sectorial tides have different distributions from the surface down to the CMB, the lunisolar stress cannot influence the break-out of every seismological event in the same degree. The influencing lunisolar effect of the solid earth tides on earthquake occurrences is connected first of all with stress components acting parallel to the surface of the Earth. The influence of load tides is limited to the loaded area and its immediate vicinity." So it is possible that the theory is undershooting what the evidence is showing in terms of strain needed to trigger an earthquake. 
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16.

What's interesting is that a critical review is added:

Without statistical testing, claims of correlating individual earthquakes and something else (in this case LOD) are worthless. LOD changes are not associated with any torques, and the associated accelerations are tiny (the velocity changes are a few micrometers/sec, and the accelerations are 10**-12g). No explanation of "resonance enlargement" is provided. Also, LOD changes are not associated with changes in torque.

Author's response

LOD variations are caused by changing Moon’s and Sun’s declinations by which the Earth is deformed. Resulting velocity changes exerts torques which are not tiny but reaches values stated above exceeding in many cases seismic moments.Tidal resonances are very common in ocean tides and there is no reason not to be in solid tides. Their existence is evident from Fig. 5a where consequently increasing LOD maxima end with Moon’s perigee. Effect of resonances is evident on many large earthquakes as Gorkha 2015, HinduKush 2015, Denali Fault 2002 and others

This is the basis of the critical response, where Agnew was the reviewer: Vidale, John E., et al. "Absence of earthquake correlation with Earth tides: An indication of high preseismic fault stress rate." Journal of Geophysical Research: Solid Earth 103.B10 (1998): 24567-24572.

Comment Source:Paper from 2016 https://www.researchgate.net/publication/303460211_Tides_as_triggers_of_earthquakes_in_Hindu_Kush_Verification_of_tidal_movement_of_plates What's interesting is that a critical review is added: > Without statistical testing, claims of correlating individual earthquakes and something else (in this case LOD) are worthless. LOD changes are not associated with any torques, and the associated accelerations are tiny (the velocity changes are a few micrometers/sec, and the accelerations are 10**-12g). No explanation of "resonance enlargement" is provided. Also, LOD changes are not associated with changes in torque. Author's response > LOD variations are caused by changing Moon’s and Sun’s declinations by which the Earth is deformed. Resulting velocity changes exerts torques which are not tiny but reaches values stated above exceeding in many cases seismic moments.Tidal resonances are very common in ocean tides and there is no reason not to be in solid tides. Their existence is evident from Fig. 5a where consequently increasing LOD maxima end with Moon’s perigee. Effect of resonances is evident on many large earthquakes as Gorkha 2015, HinduKush 2015, Denali Fault 2002 and others This is the basis of the critical response, where Agnew was the reviewer: Vidale, John E., et al. "Absence of earthquake correlation with Earth tides: An indication of high preseismic fault stress rate." Journal of Geophysical Research: Solid Earth 103.B10 (1998): 24567-24572. 
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17.

Skillful prediction of multidecadal variations in volcanic forcing A. Tuel, P. Naveau, C. M. Ammann

"Stratospheric sulfate injections from explosive volcanic eruptions are a primary natural climate forcing. Improved statistical models can now capture and simulate dynamical relationships in temporal variations of binary data. Leveraging these new techniques, the presented analysis clearly indicates that the number of large eruptions in the most recent records of explosive volcanism cannot be considered to be fully random. Including dynamical dependence in our models improves their ability to reproduce the historical record and thus forms a strong basis for skill in statistical prediction. Possible geophysical mechanisms behind the identified multidecadal variations are discussed, including variations in the observed length of day."

Comment Source:[Skillful prediction of multidecadal variations in volcanic forcing](http://onlinelibrary.wiley.com/wol1/doi/10.1002/2016GL072234/abstract) A. Tuel, P. Naveau, C. M. Ammann >"Stratospheric sulfate injections from explosive volcanic eruptions are a primary natural climate forcing. Improved statistical models can now capture and simulate dynamical relationships in temporal variations of binary data. Leveraging these new techniques, the presented analysis clearly indicates that the number of large eruptions in the most recent records of explosive volcanism **cannot be considered to be fully random**. Including dynamical dependence in our models improves their ability to reproduce the historical record and thus forms a strong basis for skill in statistical prediction. Possible geophysical mechanisms behind the identified multidecadal variations are discussed, including **variations in the observed length of day**." 
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18.

A paper from USGS denies connection of large earthquakes to lunisolar forcing: https://phys.org/news/2018-01-great-earthquakes-affected-moon-phases.html

What Hough doesn't acknowledge is the triggering effect. When an earthquake is triggered, it may be influenced by a small nudge due to the vicinity of the lunisolar path. Thus, she is contradicting recent research by her colleagues at the USGS:

van der Elst, Nicholas J., et al. "Fortnightly modulation of San Andreas tremor and low-frequency earthquakes." Proceedings of the National Academy of Sciences (2016): 201524316.

Delorey, Andrew A., Nicholas J. van der Elst, and Paul A. Johnson. "Tidal triggering of earthquakes suggests poroelastic behavior on the San Andreas Fault." Earth and Planetary Science Letters 460 (2017): 164-170.

Comment Source:A paper from USGS denies connection of large earthquakes to lunisolar forcing: https://phys.org/news/2018-01-great-earthquakes-affected-moon-phases.html What Hough doesn't acknowledge is the triggering effect. When an earthquake is triggered, it may be influenced by a small nudge due to the vicinity of the lunisolar path. Thus, she is contradicting recent research by her colleagues at the USGS: van der Elst, Nicholas J., et al. "Fortnightly modulation of San Andreas tremor and low-frequency earthquakes." Proceedings of the National Academy of Sciences (2016): 201524316. Delorey, Andrew A., Nicholas J. van der Elst, and Paul A. Johnson. "Tidal triggering of earthquakes suggests poroelastic behavior on the San Andreas Fault." Earth and Planetary Science Letters 460 (2017): 164-170. 
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19.
edited June 2018

Giant earthquakes: not as random as thought

https://phys.org/news/2018-01-giant-earthquakes-random-thought.html

Larger earthquakes recur more periodically: New insights in the megathrust earthquake cycle from lacustrine turbidite records in south-central Chile

https://www.sciencedirect.com/science/article/pii/S0012821X17305757?via=ihub

A known repeat cycle of anomalistic/draconic/synodic/annual lunisolar periodic variations is 353372 years. Within that span, there is a single maximal gravitational forcing that the moon and sun apply to the earth.

From Keeling Whorf

Tides, and the pull of the moon and sun

Comment Source:>Giant earthquakes: not as random as thought >https://phys.org/news/2018-01-giant-earthquakes-random-thought.html ![](https://imageshack.com/a/img924/6492/rYeg70.gif) >Larger earthquakes recur more periodically: New insights in the megathrust earthquake cycle from lacustrine turbidite records in south-central Chile >https://www.sciencedirect.com/science/article/pii/S0012821X17305757?via%3Dihub A known repeat cycle of anomalistic/draconic/synodic/annual lunisolar periodic variations is <strike>353</strike>372 years. Within that span, there is a single maximal gravitational forcing that the moon and sun apply to the earth. From Keeling Whorf ![kw](https://imageshack.com/a/img923/275/EkQMAG.png) Example: [The Super Blue Blood Moon Wednesday Is Something the US Hasn't Seen Since 1866](https://www.space.com/39532-super-blue-blood-moon-occurs-wednesday.html) [Tides, and the pull of the moon and sun](http://earthsky.org/earth/tides-and-the-pull-of-the-moon-and-sun) ![](http://en.es-static.us/upl/2012/10/spring_tide.gif) 
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20.

A Nature sponsored article written by a scientist at the National Institute of Mental Health

"Bipolar mood cycles and lunar tidal cycles" https://www.nature.com/articles/mp2016263

Other recent articles on tidal forcings applied to plant growth cycles

Comment Source:A Nature sponsored article written by a scientist at the National Institute of Mental Health > "Bipolar mood cycles and lunar tidal cycles" https://www.nature.com/articles/mp2016263 Other recent articles on tidal forcings applied to plant growth cycles > "Control of plant leaf movements by the lunisolar tidal force" https://academic.oup.com/aob/advance-article-abstract/doi/10.1093/aob/mcx214/4823047 > "Are there tides within trees?" https://academic.oup.com/aob/advance-article-abstract/doi/10.1093/aob/mcx215/4823029 
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21.

Tnx. I'll check out the plant papers. A correlation between full moons and increased testosterone levels has been long averred.

Comment Source:Tnx. I'll check out the plant papers. A correlation between full moons and increased testosterone levels has been long averred.
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22.

T'day, 12 years since Lusi started to erupt in Indonesia. 40,000 people lost homes. But Elsevier also publish shockingly imbalanced Special Issue on this https://www.sciencedirect.com/journal/marine-and-petroleum-geology/vol/90 We redress this http://seismo.berkeley.edu/~manga/tingayetal2018.pdf

Abstract

The cause of the Lusi mud eruption remains controversial. The review by Miller and Mazzini (2017) firmly dismisses a role of drilling operations at the adjacent Banjarpanji-1 well and argues that the eruption was triggered by the M6.3 Yogyakarta earthquake some 254 km away. We disagree with these conclusions. We review drilling data and the daily drilling reports, which clearly confirm that the wellbore was not intact and that there was a subsurface blowout. Downhole pressure data from Lusi directly witness the birth of Lusi at the surface on the 29th of May 2006, indicating a direct connection between the well and the eruption.

Comment Source:https://twitter.com/NCLRichard/status/1001466547565670400 > T'day, 12 years since Lusi started to erupt in Indonesia. 40,000 people lost homes. But Elsevier also publish shockingly imbalanced Special Issue on this > https://www.sciencedirect.com/journal/marine-and-petroleum-geology/vol/90 > We redress this >http://seismo.berkeley.edu/~manga/tingayetal2018.pdf Abstract > The cause of the Lusi mud eruption remains controversial. The review by Miller and Mazzini (2017) firmly dismisses a role of drilling operations at the adjacent Banjarpanji-1 well and argues that the eruption was triggered by the M6.3 Yogyakarta earthquake some 254 km away. We disagree with these conclusions. We review drilling data and the daily drilling reports, which clearly confirm that the wellbore was not intact and that there was a subsurface blowout. Downhole pressure data from Lusi directly witness the birth of Lusi at the surface on the 29th of May 2006, indicating a direct connection between the well and the eruption.
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23.

I'd never heard of mud eruptions or thought about drilling and landslides.

Comment Source:I'd never heard of mud eruptions or thought about drilling and landslides. 
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24.

Another article with good evidence of a lunar quake connection

https://www.sciencedirect.com/science/article/pii/S0013794418300687#! Acoustic, electromagnetic, and neutron emissions as seismic precursors: The lunar periodicity of low-magnitude seismic swarms

Comment Source:Another article with good evidence of a lunar quake connection https://www.sciencedirect.com/science/article/pii/S0013794418300687#! Acoustic, electromagnetic, and neutron emissions as seismic precursors: The lunar periodicity of low-magnitude seismic swarms 
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25.
edited February 4

That seems promising, pity it's paywalled. It would be interesting to see their data.

Comment Source:That seems promising, pity it's paywalled. It would be interesting to see their data.
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26.

Jim, Looked somewhat convincing. They are looking at the active zone in the middle of Italy, where they really need advance warnings.

Comment Source:Jim, Looked somewhat convincing. They are looking at the active zone in the middle of Italy, where they really need advance warnings. ![](https://imageshack.com/a/img922/6862/fzo5sc.gif) 
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27.

I don't think they mentioned Italy in the abstract but now I recognised that there was a piece in Nature in the wake of the fortunately unsuccessful attempted prosecution of seismologists.

Comment Source:I don't think they mentioned Italy in the abstract but now I recognised that there was a piece in Nature in the wake of the fortunately unsuccessful attempted prosecution of seismologists. 
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28.

Likely impossible to create a model for predicting magnitude 9 earthquakes -- because they are so rare. But predicting magnitude 6 via models may be a more likely way to make progress, see YouTube

Comment Source:Likely impossible to create a model for predicting magnitude 9 earthquakes -- because they are so rare. But predicting magnitude 6 via models may be a more likely way to make progress, see [YouTube](https://youtu.be/U1PJH6DAsCw?t=1380) https://youtu.be/U1PJH6DAsCw?t=1380 
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29.

Research studying earthquake precursors via analyzing fore-shocks

https://www.nationalgeographic.com/science/2019/08/earthquakes-groundbreaking-catalog-solved-seismic-mystery-foreshocks-southern-california/

This is the important part for analysis

"That’s why the new quake catalog presented such a tantalizing opportunity. Published earlier this year in Science, that colossal effort pinpointed 1.81 million earthquakes that shook Southern California between 2008 and 2017, all the way down to magnitude 0.3."

https://www.nationalgeographic.com/science/2019/04/every-three-minutes-one-earthquake-california/

• Searching for hidden earthquakes in Southern California

https://science.sciencemag.org/content/364/6442/767

"This effort resulted in a catalog with 1.81 million earthquakes, a 10-fold increase, which provides important insights into the geometry of fault zones at depth, foreshock behavior and nucleation processes, and earthquake-triggering mechanisms. The rich detail resolved in this type of catalog will facilitate the next generation of analyses of earthquakes and faults."

Comment Source:Research studying earthquake precursors via analyzing fore-shocks https://www.nationalgeographic.com/science/2019/08/earthquakes-groundbreaking-catalog-solved-seismic-mystery-foreshocks-southern-california/ This is the important part for analysis >"That’s why the new quake catalog presented such a tantalizing opportunity. Published earlier this year in Science, that colossal effort pinpointed 1.81 million earthquakes that shook Southern California between 2008 and 2017, all the way down to magnitude 0.3." https://www.nationalgeographic.com/science/2019/04/every-three-minutes-one-earthquake-california/ - Searching for hidden earthquakes in Southern California https://science.sciencemag.org/content/364/6442/767 > "This effort resulted in a catalog with 1.81 million earthquakes, a 10-fold increase, which provides important insights into the geometry of fault zones at depth, foreshock behavior and nucleation processes, and earthquake-triggering mechanisms. The rich detail resolved in this type of catalog will facilitate the next generation of analyses of earthquakes and faults." 
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30.
edited August 2019

Tnx. I saw the Nat. Geog. April report. Hopefully they'll be able to produce a global catalogue so people in developing countries will be able to get landslide warnings but that won't occur until they've got the sensor networks.

Comment Source:Tnx. I saw the Nat. Geog. April report. Hopefully they'll be able to produce a global catalogue so people in developing countries will be able to get landslide warnings but that won't occur until they've got the sensor networks.
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31.

I am thinking some intrepid amateurs will eventually data mine the catalog for correlations.

Comment Source:I am thinking some intrepid amateurs will eventually data mine the catalog for correlations.
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32.

I had a brief look at reported landslides and had another of my unrealisable fantasy projects of automatic scanning for vulnerable communities using the google earth 3D api.

Comment Source:I had a brief look at reported landslides and had another of my unrealisable fantasy projects of automatic scanning for vulnerable communities using the google earth 3D api.
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33.

Pervasive Foreshock Activity Across Southern California

"Foreshocks have been documented as preceding less than half of all mainshock earthquakes. These observations are difficult to reconcile with laboratory earthquake experiments and theoretical models of earthquake nucleation, which both suggest that foreshock activity should be nearly ubiquitous. Here we use a state‐of‐the‐art, high‐resolution earthquake catalog to study foreshock sequences of magnitude M4 and greater mainshocks in southern California from 2008–2017. This highly complete catalog provides a new opportunity to examine smaller magnitude precursory seismicity. "

Comment Source:[Pervasive Foreshock Activity Across Southern California](https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL083725) > "Foreshocks have been documented as preceding less than half of all mainshock earthquakes. These observations are difficult to reconcile with laboratory earthquake experiments and theoretical models of earthquake nucleation, which both suggest that foreshock activity should be nearly ubiquitous. Here we use a state‐of‐the‐art, high‐resolution earthquake catalog to study foreshock sequences of magnitude M4 and greater mainshocks in southern California from 2008–2017. This highly complete catalog provides a new opportunity to examine smaller magnitude precursory seismicity. " 
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34.

Andrew Ng regularly emails interesting ML news.

Geologists call them slow slips: deep, low-frequency earthquakes that can last a month but have little effect on the surface. A model trained to predict such events could help with forecasting potentially catastrophic quakes. What's new: French and American seismologists trained a model to recognize acoustic patterns associated with slow slips where one tectonic plate slides beneath another. Some seismologists believe that slow slips shift stress from deep in a geological fault up to the Earth's brittle crust, presaging potentially catastrophic quakes. How it works: The authors began by simulating slow slips in the lab using two sheets of synthetic material, like acrylic plastic, separated by a thin layer of a granular, sandy medium. The video above is a microscopic view of the sheets in action.

The researchers recorded the acoustic signals emitted by the sheets and granular layer as they compressed. Then they divided the recording into short segments and fed them into a random forest model.
The model found that the signal’s gradual variance from mean — rather than big, sudden jumps just before a slip — was the best predictor that the sheets were about to experience a laboratory version of a slow slip.
Having ingested seismic data from the tectonic plate that runs from Canada to California between 2007 and 2013, the model predicted four of the five slow slips that occurred between 2013 and 2018.


We’re thinking: Seismologists already provide short-term risk assessments for a given location and time span. This research could lead to long-term forecasts, months or years out, allowing planners to expedite earthquake safety upgrades that otherwise may be delayed due to their cost.

Comment Source:Andrew Ng regularly emails interesting ML news. * [Prelude to a Quake?](https://mail.google.com/mail/u/0/#inbox/FMfcgxwDrbsZwbjTDJqldGzvgLQXghpl) Geologists call them slow slips: deep, low-frequency earthquakes that can last a month but have little effect on the surface. A model trained to predict such events could help with forecasting potentially catastrophic quakes. What's new: French and American seismologists trained a model to recognize acoustic patterns associated with slow slips where one tectonic plate slides beneath another. Some seismologists believe that slow slips shift stress from deep in a geological fault up to the Earth's brittle crust, presaging potentially catastrophic quakes. How it works: The authors began by simulating slow slips in the lab using two sheets of synthetic material, like acrylic plastic, separated by a thin layer of a granular, sandy medium. The video above is a microscopic view of the sheets in action. The researchers recorded the acoustic signals emitted by the sheets and granular layer as they compressed. Then they divided the recording into short segments and fed them into a random forest model. The model found that the signal’s gradual variance from mean — rather than big, sudden jumps just before a slip — was the best predictor that the sheets were about to experience a laboratory version of a slow slip. Having ingested seismic data from the tectonic plate that runs from Canada to California between 2007 and 2013, the model predicted four of the five slow slips that occurred between 2013 and 2018. We’re thinking: Seismologists already provide short-term risk assessments for a given location and time span. This research could lead to long-term forecasts, months or years out, allowing planners to expedite earthquake safety upgrades that otherwise may be delayed due to their cost. * Claudia Hubert et al., [A Silent Build-up in Seismic Energy Precedes Slow Slip Failurein the Cascadia Subduction Zone (2019)](https://arxiv.org/pdf/1909.06787.pdf)
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35.

This study correlates the 6.4 year envelope of Chandler Wobble with magma eruptions on Mt. Etna

https://phys.org/news/2019-12-earth-earthquakes-volcanic-eruptions-mount.html

Lambert, S. & Sottili, G. Is there an influence of the pole tide on volcanism? Insights from Mount Etna recent activity. Geophysical Research Letters (2019) doi:10.1029/2019GL085525.

“The tide from polar motion causes the crust to deform over the span of seasons or years. This distortion is strongest at 45 degrees latitude, where the crust moves by about 1 centimeter (0.4 inches) per year.”

And from earlier in the year, Tamino found this correlation of Chandler Wobble with sea-level rise oscillations at mid-latitudes along the USA east cost:

https://tamino.wordpress.com/2019/01/12/wobbly-sea-level-rise-u-s-east-coast-vi/

Comment Source:This study correlates the 6.4 year envelope of Chandler Wobble with magma eruptions on Mt. Etna https://phys.org/news/2019-12-earth-earthquakes-volcanic-eruptions-mount.html Lambert, S. & Sottili, G. Is there an influence of the pole tide on volcanism? Insights from Mount Etna recent activity. Geophysical Research Letters (2019) doi:10.1029/2019GL085525. > “The tide from polar motion causes the crust to deform over the span of seasons or years. This distortion is strongest at 45 degrees latitude, where the crust moves by about 1 centimeter (0.4 inches) per year.” And from earlier in the year, Tamino found this correlation of Chandler Wobble with sea-level rise oscillations at mid-latitudes along the USA east cost: https://tamino.wordpress.com/2019/01/12/wobbly-sea-level-rise-u-s-east-coast-vi/ 
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36.
edited January 4

Andrew Ng cites cites the California ML paper you referred to:

in his excellent 'The Batch':

Comment Source:Andrew Ng cites cites the California ML paper you referred to: * http://bit.ly/36r16vW in his excellent 'The Batch': * http://bit.ly/37AxBYF
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37.

I believe this kind of ML only uses past information from the time-series. Thus, it can only find natural amplitude/phase responses or resonances that are internal but not identify any external forcing sources. If an ML algorithm could use this info PLUS other sources of data PLUS arbitrary symbolic algebraic transformations, then it might really start to find connections.

Comment Source:I believe this kind of ML only uses past information from the time-series. Thus, it can only find natural amplitude/phase responses or resonances that are internal but not identify any external forcing sources. If an ML algorithm could use this info PLUS other sources of data PLUS arbitrary symbolic algebraic transformations, then it might really start to find connections.
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38.
edited February 7

Interesting that the paper cited in #20 has been retracted by Oxford Academic publishers

This retraction was discovered via my Zoteria citation database, "Control of plant leaf movements by the lunisolar tidal force"

Even though it's apparently self-plagiarization, I never would have been aware of this research if I hadn't run across this paper.

Comment Source:Interesting that the paper cited in [#20](https://forum.azimuthproject.org/discussion/comment/18570/#Comment_18570) has been retracted by Oxford Academic publishers This retraction was discovered via my Zoteria citation database, ["Control of plant leaf movements by the lunisolar tidal force"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6007428/) ![](https://pbs.twimg.com/media/EPoqi2aWoAAMRZz.png) Even though it's apparently self-plagiarization, I never would have been aware of this research if I hadn't run across this paper. 
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39.

This is compelling research from Roma : "Tidal modulation of plate motions" https://www.sciencedirect.com/science/article/pii/S0012825220302257

"The dynamics of a long-lasting effusive eruption modulated by Earth tides" https://www.sciencedirect.com/science/article/abs/pii/S0012821X20300881

Comment Source:This is compelling research from Roma : "Tidal modulation of plate motions" https://www.sciencedirect.com/science/article/pii/S0012825220302257 --- "The dynamics of a long-lasting effusive eruption modulated by Earth tides" https://www.sciencedirect.com/science/article/abs/pii/S0012821X20300881 
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40.

Wow, great memories! I was a seismologist in the USAF 1978 - 1981 at AFTAC monitoring the nuclear test ban treaty. We were probably a decade ahead of anyone else with our unlimited budget.

Comment Source:Wow, great memories! I was a seismologist in the USAF 1978 - 1981 at [AFTAC](https://www.16af.af.mil/Units/AFTAC/) monitoring the nuclear test ban treaty. We were probably a decade ahead of anyone else with our unlimited budget.
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41.

I haven't looked for awhile, but there seems to be more recent papers that connect lunar gravitational triggering to earthquake activity:

• A Myth of Preferred Days of Strong Earthquakes? Vladimir G. Kossobokov; Giuliano F. Panza Seismological Research Letters (2020) 91 (2A): 948–955. https://doi.org/10.1785/02201901

"On the other hand, the same Kuiper test permits the rejection of the null hypotheses of the same chance of occurrence on any JD or MP for strong magnitude M≥6.0 earthquakes, at least for the past four decades of presumably the best‐earthquake determinations and, in particular, for earthquakes in the Northern Hemisphere (with an evident seasonal pattern). The nonparametric two‐sample Kolmogorov–Smirnov test statistics suggest no preferred distances to the Moon at the occurrence of large earthquakes. All of this contributes, to the results of solid statistical testing of hypotheses, for a better understanding of the complex seismic response of the Earth’s lithosphere to periodic gravitational loading."

Hough who apparently is the head of the USGS office in Pasadena gets challenged in this one:

"Correlation of giant earthquakes with the lunar phase in seven Indo-Pacific 2 subduction zones and around Mongolia" => "The most important point of this research is that we divided the earthquakes by their locations. Hough (2018) carried out simple simulations and concluded that the occurrence of MW > 8 earthquakes ~1900 onward had nothing to do with lunar phases. However, her conclusion is inadequate since she analyzed all events at the same time without considering their locations. "

Wow, this is quite a smackdown. Why a geophysicist wouldn't consider that the distance from the moon to the earth varies in both time and geospatial location is perplexing. What do you think @DanielGeisler ?

And regarding seismology, this is an absolute killer study in how the long period lunar tropical tide Mf is strongly detectable at the bottom of the ocean

• Tidal Triggering of the Harmonic Noise in Ocean‐Bottom Seismometers Telluri Ramakrushana Reddy; Pawan Dewangan; Lalit Arya; Pabitra Singha; Kattoju Achuta Kamesh Raju Seismological Research Letters (2020) 91 (2A): 803–813. https://doi.org/10.1785/0220190080

" It is likely that the HN observed in the present study is related to seafloor currents generated by tides."

Comment Source:I haven't looked for awhile, but there seems to be more recent papers that connect lunar gravitational triggering to earthquake activity: * A Myth of Preferred Days of Strong Earthquakes? Vladimir G. Kossobokov; Giuliano F. Panza Seismological Research Letters (2020) 91 (2A): 948–955. https://doi.org/10.1785/02201901 > "On the other hand, the same Kuiper test permits the rejection of the null hypotheses of the same chance of occurrence on any JD or MP for strong magnitude M≥6.0 earthquakes, at least for the past four decades of presumably the best‐earthquake determinations and, in particular, for earthquakes in the Northern Hemisphere (with an evident seasonal pattern). The nonparametric two‐sample Kolmogorov–Smirnov test statistics suggest no preferred distances to the Moon at the occurrence of large earthquakes. All of this contributes, to the results of solid statistical testing of hypotheses, for a better understanding of the complex seismic response of the Earth’s lithosphere to periodic gravitational loading." Hough who [apparently is the head of the USGS office in Pasadena](https://en.wikipedia.org/wiki/Susan_Hough) gets challenged in this one: > "Correlation of giant earthquakes with the lunar phase in seven Indo-Pacific 2 subduction zones and around Mongolia" => "The most important point of this research is that we divided the earthquakes by their locations. Hough (2018) carried out simple simulations and concluded that the occurrence of MW > 8 earthquakes ~1900 onward had nothing to do with lunar phases. However, her conclusion is inadequate since she analyzed all events at the same time **without considering their locations.** " Wow, this is quite a smackdown. Why a geophysicist wouldn't consider that the distance from the moon to the earth varies in both time and geospatial location is perplexing. What do you think @DanielGeisler ? --- And regarding seismology, this is an absolute killer study in how the long period lunar tropical tide **Mf** is strongly detectable at the bottom of the ocean * Tidal Triggering of the Harmonic Noise in Ocean‐Bottom Seismometers Telluri Ramakrushana Reddy; Pawan Dewangan; Lalit Arya; Pabitra Singha; Kattoju Achuta Kamesh Raju Seismological Research Letters (2020) 91 (2A): 803–813. https://doi.org/10.1785/0220190080 ![](https://imagizer.imageshack.com/img922/9657/Y0rXdg.png) > " It is likely that the HN observed in the present study is related to seafloor currents generated by tides." 
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42.

@WebHubTel - I worked with people with a PhD. in Geophysics, but they still thought in the box. So I can easily see someone not considering the full dynamics of the moon. Hopefully we can provide a more mature discussion because of our system's perspective. Let me summarize my understanding of some important points.

1. tidal forces with the moon add to the heating of the climate.

2. tidal forces also induce volcanic action which needs to be factored in to climate change.

3. there are serious problems with not knowing the origin of the climate data set.

4. the dynamics of the moon need to taken into account to fully understand climate change and that this heating is notable when compared with anthropomorphic heating.

• downsizing human activity might not be enough to cool the planet.

• what can be done to manage the tidal impact?

Comment Source:@WebHubTel - I worked with people with a PhD. in Geophysics, but they still thought in the box. So I can easily see someone not considering the full dynamics of the moon. Hopefully we can provide a more mature discussion because of our system's perspective. Let me summarize my understanding of some important points. 1. tidal forces with the moon add to the heating of the climate. 2. tidal forces also induce volcanic action which needs to be factored in to climate change. 3. there are serious problems with not knowing the origin of the climate data set. 4. the dynamics of the moon need to taken into account to fully understand climate change and that this heating is notable when compared with anthropomorphic heating. * downsizing human activity might not be enough to cool the planet. * what can be done to manage the tidal impact?
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43.

"tidal forces with the moon add to the heating of the climate."

I would not take it that far since it could also lead to cooling, functioning in total as a zero-sum effect.

This is assuming the overall dynamics are analogous to sea-level rise -- the rise and fall of ocean tides are also zero-sum.

Comment Source:> "tidal forces with the moon add to the heating of the climate." I would not take it that far since it could also lead to cooling, functioning in total as a zero-sum effect. This is assuming the overall dynamics are analogous to sea-level rise -- the rise and fall of ocean tides are also zero-sum. 
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44.
edited June 20

the dynamics of the moon need to taken into account to fully understand climate change and that this heating is notable when compared with anthropomorphic

How would lunar cycles account for the sharp increase in average global temperatures, over a short recent historical time span -- which is notable for the strong correlation with the production of greenhouse gasses? And it's not just a correlation. Isn't this a causal relation predicted by basic physical theory?

Comment Source:> the dynamics of the moon need to taken into account to fully understand climate change and that this heating is notable when compared with anthropomorphic How would lunar cycles account for the sharp increase in average global temperatures, over a short recent historical time span -- which is notable for the strong correlation with the production of greenhouse gasses? And it's not _just_ a correlation. Isn't this a causal relation predicted by basic physical theory?
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45.
edited June 20

I think I am taking David's side on this -- the best that the lunar forcing modeling can do is provide discrimination of natural zero-sum cyclical changes from the long-term monotonic (often labelled secular) changes due to GHG forcing. I have to be very careful distinguishing the two, as people often assume that the modeling of ENSO I am doing is somehow counter to the prevailing AGW theory, and so also assume that I am an AGW skeptic. Wrong :(

This is a latest chart -- notice that the very long-term tidal terms, corresponding to 18.6 and 8.85 years at the bottom-right inset are not a contributing factor to the ENSO model.

BTW, the correct term is anthropogenic and not anthropomorphic, as the latter applies human characteristics to a phenomena.

Comment Source:I think I am taking David's side on this -- the best that the lunar forcing modeling can do is provide discrimination of natural zero-sum cyclical changes from the long-term monotonic (often labelled secular) changes due to GHG forcing. I have to be very careful distinguishing the two, as people often assume that the modeling of ENSO I am doing is somehow counter to the prevailing AGW theory, and so also assume that I am an AGW skeptic. Wrong :( This is a latest chart -- notice that the very long-term tidal terms, corresponding to 18.6 and 8.85 years at the bottom-right inset are not a contributing factor to the ENSO model. ![](https://imagizer.imageshack.com/img922/3587/kruDds.png) BTW, the correct term is anthropogenic and not anthropomorphic, as the latter applies human characteristics to a phenomena. 
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46.

That's an important clarification. I think that it is worth emphasizing when presenting your work, because without being put into full context, it is easy to give an erroneous interpretation of these results -- and some folks with an agenda would probably like to use it for dishonorable purposes. (I'm not talking about anyone here on this forum!!)

Truth is truth, but some of the truth taken out of context can bolster denial and dishonesty.

Comment Source:That's an important clarification. I think that it is worth emphasizing when presenting your work, because without being put into full context, it is easy to give an erroneous interpretation of these results -- and some folks with an agenda would probably like to use it for dishonorable purposes. (I'm not talking about anyone here on this forum!!) Truth is truth, but some of the truth taken out of context can bolster denial and dishonesty. 
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47.

Here is one possible response, which I would attribute to innocent confusion: since the moon has an effect on temperature, it's out of our hands, so there's no point in worrying about carbon emissions. The fallacy here is to assume that multiple causes do not have to be considered and assessed independently - it's always one thing or another.

Comment Source:Here is one possible response, which I would attribute to innocent confusion: since the moon has an effect on temperature, it's out of our hands, so there's no point in worrying about carbon emissions. The fallacy here is to assume that multiple causes do not have to be considered and assessed independently - it's always one thing or another. 
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48.

More than that, the relative strengths of the factors needs to be quantified!

Comment Source:More than that, the relative strengths of the factors needs to be quantified!
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49.
edited June 21

Paul, do you have a way of quantifying the contributions of tidal vs. greenhouse effects to global warming?

Comment Source:Paul, do you have a way of quantifying the contributions of tidal vs. greenhouse effects to global warming? 
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50.

One thing you indicated is that tidal effects are not biased either towards warming or cooling, so it is conceivable that lately tidal effects have had a cooling effect on the planet.

Comment Source:One thing you indicated is that tidal effects are not biased either towards warming or cooling, so it is conceivable that lately tidal effects have had a _cooling_ effect on the planet.