From NASA’s Jet Propulsion Lab: The March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day and shifted its axis. But don’t worry-you won’t notice the difference.
Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake-the fifth largest since 1900-affected Earth’s rotation. His calculations indicate that by changing the distribution of Earth’s mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).
The calculations also show the Japan quake should have shifted the position of Earth’s figure axis (the axis about which Earth’s mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth’s figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth’s figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth’s axis in space-only external forces such as the gravitational attraction of the sun, moon and planets can do that.
Both calculations will likely change as data on the quake are further refined.
In comparison, following last year’s magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth’s figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth’s figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth’s rotation depends on its size (magnitude), location and the details of how the fault slipped.
Gross said that, in theory, anything that redistributes Earth’s mass will change Earth’s rotation.
“Earth’s rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents,” he said. “Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake. The position of Earth’s figure axis also changes all the time, by about 1 meter (3.3 feet) over the course of a year, or about six times more than the change that should have been caused by the Japan quake.”
Gross said that while we can measure the effects of the atmosphere and ocean on Earth’s rotation, the effects of earthquakes, at least up until now, have been too small to measure. The computed change in the length of day caused by earthquakes is much smaller than the accuracy with which scientists can currently measure changes in the length of the day. However, since the position of the figure axis can be measured to an accuracy of about 5 centimeters (2 inches), the estimated 17-centimeter shift in the figure axis from the Japan quake may actually be large enough to observe if scientists can adequately remove the larger effects of the atmosphere and ocean from the Earth rotation measurements. He and other scientists will be investigating this as more data become available.
Gross said the changes in Earth’s rotation and figure axis caused by earthquakes should not have any impacts on our daily lives. “These changes in Earth’s rotation are perfectly natural and happen all the time,” he said. “People shouldn’t worry about them.”
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Re: Bill Illis
…And compare with global seismicity (Centennial Earthquake Catalog) – and rate of change of solar wind speed and rate of change of neutron count rates (proxy for cosmic ray flux). Nonrandom relations — but those who ignore the spatial dimension (and just run temporal spectral analyses) will draw fundamentally flawed conclusions. Spatial phase reversals are being misinterpreted as temporal features. The phase of interannual NPI, for example, can be observed to fit the phase of rate of change of the above-mentioned solar indices if one simply realizes the effect of spatial windowing parameters on summaries. The mainstream has fallen victim to the spatiotemporal version of Simpson’s Paradox.
Pamela Gray wrote, “However, I trust climate scientists to eventually splice together a graph that shows it does, theoretically.”
There’s a roughly monotonic trend in decadal extent AAM & LOD power at both semi-annual & annual grain (but since the vast majority of the mainstream ignores extent, this will likely remain unnoticed).
I’ve been wondering how long it might take some enterprising AGW alarmist to attempt to capitalize empirically upon the preceding.
Paul Vaughan says:
March 17, 2011 at 8:13 pm
…And compare with global seismicity (Centennial Earthquake Catalog) – and rate of change of solar wind speed and rate of change of neutron count rates (proxy for cosmic ray flux). Nonrandom relations
My analysis http://www.leif.org/research/Earthquake-Activity.png is conclusive. There is no hint of any increase in earthquake activity following geomagnetic storms, because if they did, there would be a larger number of earthquakes on the day of the storm [or the next day], and there isn’t. The solar wind speed is organized by sector boundaries, but passage of these also have no signal in global seismicity.
Re: Leif Svalgaard
You have misunderstood what I wrote (or perhaps simply seized what appeared as an opportunity to denounce the claims of others?)
Paul Vaughan says:
March 17, 2011 at 9:32 pm
You have misunderstood what I wrote
Perhaps be less opaque, then.
One articale about the impact of the pole shift on tectonic plates:
http://www.earth-issues.com/2011/03/geomagnetic-pole-shift-triggering-massive-superquakes-2/
This is not a technical paper . I’m not sure who the author is.
On the external influences to earth’s magnetic field, an earthquake due to a magnetic storm would not be immediate. The lag factor would at least depend on the existing pressure built up of the plates and the size of the CME.
JudyW says:
March 18, 2011 at 7:17 am
On the external influences to earth’s magnetic field, an earthquake due to a magnetic storm would not be immediate. The lag factor would at least depend on the existing pressure built up of the plates and the size of the CME.
Examining ALL such storms over the last 100 years shows that there is no such increase in the number of earthquakes on the day of the storm [or on any other day up to a hundred days after the storm for that matter]. As simple as that: http://www.leif.org/research/Earthquake-Activity.png which shows the number of earthquakes on the day of the storm at 0, one day after the storm at 1, etc.
The blue and the red points are from two different Earthquake Catalogs [the red going to slightly lower energy 5.5 Richter than the blue 6, hence the higher number].
Leif, you’re missing some fundamentals about the effect of integration across spatiotemporal harmonics.
Paul Vaughan says:
March 18, 2011 at 7:21 pm
Leif, you’re missing some fundamentals about the effect of integration across spatiotemporal harmonics.
No less opaque.
Paul Vaughan says:
March 18, 2011 at 7:21 pm
Leif, you’re missing some fundamentals about the effect of integration across spatiotemporal harmonics.
the quantities you were mentioning are hardly ‘spatiotemporal’ except in the trivial sense that everything exists in space and time [or even spacetime]. The ‘harmonics’ bit is extraneous as these quantities are not oscillators. But in solar physics we do have genuine spatiotemporal variables and we do know how to deal with them. No ‘fundamentals’ are missing. Here is a good example: http://soi.stanford.edu/results/td.html
Note how [last figure] data is plotted against both space [abscissa] and time [ordinate].
Leif, the issue is with sampling intervals (and the effect on statistical summaries of pattern). In layman’s terms, I am raising issues with apples and you are commenting about oranges. My commentary is deliberately brief to save time, so I accept responsibility for misunderstandings arising due to lack of elaboration. To clarify, the “apples” include not only NPI & global seismicity, but also SOI, SAM, AAO, AO, NAO, PDO’, AMO’, HadSST’, PWP, VEI, IVI2, SAOT, MSI, DVI, CO2′, LOD’, AAM, QBO, & others. Many analysts are misinterpreting spatial phase reversals as temporal features [due to a fundamental lack of awareness of (a) the effect of windowing parameters on statistical summaries of pattern and (b) the effect on pattern of integration across spatiotemporal harmonics]. Since related misunderstandings arising in the mainstream are so fundamental, I estimate that it could take decades to correct the widespread misinterpretations. The required teachings are challenging even for talented educators and the pool of citizens capable of grasping the concepts is limited.
Paul Vaughan says:
March 20, 2011 at 9:10 am
Leif, the issue is with sampling intervals (and the effect on statistical summaries of pattern). In layman’s terms, I am raising issues with apples and you are commenting about oranges.
The sampling intervals are irrelevant. When comparing, once always uses the same sampling interval for both [or all] quantities. Understanding of what a ‘sampling’ interval is may be sorely lacking. For example, the solar wind speed may be in reality sampled every few seconds. From such fine-grained data it is customary to form, say, hourly of daily averages. This is legitimate because there is a very high degree of autocorrelation [or to use the older word: positive conservation] in the data, i.e. the solar wind speed from one second to the next is almost the same.
Many analysts are misinterpreting spatial phase reversals as temporal features
Most of these quantities don’t have spatial phase reversals, e.g. the global temperature or TSI. Explain what spatial phase reversals are appropriate for those.
Leif, I apologize as I’ve limited time, so I’ll just list some of the things on my mind as I’ve commented:
EXTENT (not just grain),
SPATIAL sampling interval (not just temporal!) …and shape matters too, not just area,
multiscale spatial heterogeneity,
depth & altitude (“global” isn’t just a skin),
leverage (on statistical summaries by outliers, such as high amplitude regions…) – e.g. weighting (for example by specific heat – e.g. continental vs. maritime – e.g. why AMO’ relates more closely than SOI to HadSST’…)
The preceding’s not exhaustive – just suggestive.
I’ll elaborate briefly:
Plant ecologists throw down quadrats to measure pattern. If they change the quadrat size they measure a different pattern (particularly if there is clustering at some scale or another, etc.) IT’S NOT ENOUGH TO JUST PICK ONE SIZE AND STICK WITH IT; plenty of scolding articles, lectures, & presentations have been painstakingly made to emphasize (like thunder) this ABSOLUTELY CRUCIAL point. One EASILY finds paradoxes, scale discontinuites, etc. Take the word ‘paradox’ literally – (a good example to which lay-people can easily relate is the redrawing of electoral boundaries to favor a party). [Note: Some physical geographers refer to this as the “modifiable areal unit problem”, sometimes abbreviated MAUP.]
I trust that you get the essence without need for protracted exchange. My comments are most strongly influenced by the following subset of variables: NPI, AO, NAO, NAM, SAM, AAO, COWL, & SOI. Perhaps there will be time to elaborate further some less busy day (for example as to why simple linear methods canNOT handle this job). In the meantime I encourage you to have a look at some (not necessarily all) of what Tomas Milanovic has been saying over at Climate Etc. While I disagree fundamentally with him on some issues, I appreciate that he is aware of many of the windowing issues which I have described here; Milanovic is one of very few engaged in the online climate discussion possessing (& expressing explicitly) this awareness.
Climate science has itself tied in a knot by the spatiotemporal version of Simpson’s Paradox. With patience, freedom from the tangled bind is achievable.
Best Regards to All.
Paul Vaughan says:
March 21, 2011 at 10:28 pm
EXTENT (not just grain), grain????
SPATIAL sampling interval (not just temporal!) …and shape matters too, not just area,
Many analysts are misinterpreting spatial phase reversals as temporal features
Most of these quantities don’t have spatial phase reversals, e.g. the global temperature or TSI. Explain what spatial phase reversals are appropriate for those.