Japan Quake May Have Shortened Earth Days, Moved Axis
14 March 2011
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."
Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Chile Earthquake May Have Shortened Days on Earth
by SPACE.com Staff
Date: 02 March 2010
The massive 8.8 earthquake that struck Chile may have changed the entire Earth's rotation and shortened the length of days on our planet, a NASA scientist said Monday.
The quake, the seventh strongest earthquake in recorded history, hit Chile Saturday and should have shortened the length of an Earth day by 1.26 microseconds, according to research scientist Richard Gross at NASA's Jet Propulsion Laboratory in Pasadena, Calif. One microsecond is one-millionth of a second long.
Alarming NOAA data, Rapid Pole Shift
Submitted by: Ken
January 15, 2011
The NOAA National Geophysical Data Center maintains a data set of annual magnetic north pole coordinates going back to the year 1590, derived from early measurements from ships logs to modern day techniques.
Noting that there has been lots of reporting of pole shift lately, to the point where the phenomenon is actually causing real-world issues such as temporary airport closures, a deeper investigation was in order.
After transferring 420 years of north pole position data from the NOAA Geo Data Center, configuring it to fit in an Excel spreadsheet, adding a complicated formula to determine exact distance between 2 sets of latitude-longitude coordinates, applying the formula to each data point in the series, and then finally plotting it all in a visual graph, it is alarming to discover the amount of magnetic pole shift – just over the past 10 to 20 years.
Here is one very interesting fact…
Since 1860, the magnetic pole shift has more than doubled every 50 years. That is pretty significant. In geological terms, that seems to be pretty ‘rapid’.
Here is another very interesting fact…
During the past 150 years, the pole shift has been in the same direction.
The following fact is even more astonishing…
During the past 10 years, the magnetic north pole has shifted nearly half of the total distance of the past 50 years! In other words, the pole shift has apparently sped up substantially.
Pole Shift has more than doubled each of the last 50 years
The present rate of magnetic north pole shift is about 55 kilometers per year. According to the data set, during the year 2000 the magnetic north pole actually shifted more than 70 kilometers.
The issue now is, since the pole shift has been at 400 year record high rates during the past 10 to 20 years, the cumulative effect is now beginning to cause real-world issues.
Will the effects affect us noticeably or in a bad way? Time will tell I suppose, but at the current rate there will no doubt be direct effects on many systems in the years ahead, many of them nuisance issues such as documentation changes while others will likely be more serious.
It is not known if the shift will speed up or slow down in the years ahead. Some say that a pole reversal is overdue, and this phenomenon may be indicators of the beginnings of that process.
Note that the earth’s magnetic field is what protects us from radiation. Without it, we would not survive. Could a pole reversal cause a period of time in-between flip-flop such that we would be exposed to deadly radiation? Stay tuned…
Graph of annual magnetic north pole shift during the past 420 years
At the current direction, the magnetic north pole is heading directly towards Russia. The following image shows the dramatic acceleration while pointing out the past 50 years versus the past 10 years of movement.
Update: March, 2012 – NOAA has just changed (massaged?) their data of the past decade.
Why is the north magnetic pole racing toward Siberia?
By John Matson
December 24, 2010
Finding Santa Claus‘s home at the North Pole is easy on a globe—just look for the point on top where all the lines of longitude meet. But that is just the "geographic" North Pole; there are several other definitions for the poles, all useful in different scientific or navigational contexts. Among the many north poles, let us rejoice that Santa Claus did not choose the magnetic pole for his home, for he would have to spend as much time moving as delivering presents.
The north magnetic pole (NMP), also known as the dip pole, is the point on Earth where the planet’s magnetic field points straight down into the ground. Scottish explorer James Clark Ross first located the NMP in 1831 on the Boothia Peninsula in what is now northern Canada, and with the planting of a flag claimed it for Great Britain.
But the NMP drifts from year to year as geophysical processes within Earth change. For more than 150 years after Ross’s measurement its movement was gradual, generally less than 15 kilometers per year. But then, in the 1990s, it picked up speed in a big way, bolting north–northwest into the Arctic Ocean at more than 55 kilometers per year. If it keeps going it could pass the geographic north pole in a decade or so and carry on toward Siberia. But why?
One compelling explanation appears in the December 21 Eos, the weekly transactions of the American Geophysical Union. In their Eos article (subscription required), and in a longer paper published earlier in 2010 in the Journal of Geophysical Research–Solid Earth, Arnaud Chulliat of the Institute of Earth Physics of Paris and his colleagues venture that a twisting molten plume beneath the Artic could be the cause:
According to some recent models, plumes of less dense fluid form at the inner core boundary and subsequently rise within [a cylinder] whose central axis is the Earth’s rotation axis. Such plumes undergo a strong helical motion due to the Earth’s rapid rotation, a phenomenon also observed in laboratory experiments with water. In the core, helical plumes advect and twist the magnetic field lines, forming what scientists call "polar magnetic upwellings."
Those upwellings, unloaded into the Arctic mantle, could produce intense patches of magnetic activity on the sort of decade-long timescales needed to explain the NMP’s sudden acceleration. (The authors compare these patches to a kind of terrestrial version of sunspots.) And magnetic field measurements show dramatic shifts near the New Siberian Islands that seem to fit the bill.
"What happened under the New Siberian Islands at the core surface is that the rate of change of the magnetic field changed by a large amount during the 1990s," Chulliat says. That activity, he and his colleagues have found, could account for a large portion of the NMP’s acceleration. But whether magnetic field changes under the New Siberian Islands and the speeding north magnetic pole ultimately arise from a twisted plume of fluid rising through the core remains unproved, Chulliat and his co-authors note. A resolution of the mystery will await better modeling, along with more data from satellites monitoring the Arctic’s magnetic environment. The necessity of satellites, interestingly enough, is a consequence of the pole’s recent movement—as the NMP drifts farther out to sea, it becomes harder and harder to reach the region with magnetometer-equipped aircraft.
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