NASA Details Earthquake Effects on the Earth
January 10, 2005

NASA scientists using data from the Indonesian earthquake calculated it affected Earth's rotation, decreased the length of day, slightly changed the planet's shape, and shifted the North Pole by centimeters. The earthquake that created the huge tsunami also changed the Earth's rotation.

Dr. Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Dr. Benjamin Fong Chao, of NASA's Goddard Space Flight Center, Greenbelt, Md., said all earthquakes have some affect on Earth's rotation. It's just they are usually barely noticeable.

"Any worldly event that involves the movement of mass affects the Earth's rotation, from seasonal weather down to driving a car," Chao said.

Gross and Chao have been routinely calculating earthquakes' effects in changing the Earth's rotation in both length-of- day as well as changes in Earth's gravitational field. They also study changes in polar motion that is shifting the North Pole. The "mean North pole" was shifted by about 2.5 centimeters (1 inch) in the direction of 145 degrees East Longitude. This shift east is continuing a long-term seismic trend identified in previous studies.

They also found the earthquake decreased the length of day by 2.68 microseconds. Physically this is like a spinning skater drawing arms closer to the body resulting in a faster spin. The quake also affected the Earth's shape. They found Earth's oblateness (flattening on the top and bulging at the equator) decreased by a small amount. It decreased about one part in 10 billion, continuing the trend of earthquakes making Earth less oblate.

To make a comparison about the mass that was shifted as a result of the earthquake, and how it affected the Earth, Chao compares it to the great Three-Gorge reservoir of China. If filled, the gorge would hold 40 cubic kilometers (10 trillion gallons) of water. That shift of mass would increase the length of day by only 0.06 microseconds and make the Earth only very slightly more round in the middle and flat on the top. It would shift the pole position by about two centimeters (0.8 inch).

The researchers concluded the Sumatra earthquake caused a length of day change too small to detect, but it can be calculated. It also caused an oblateness change barely detectable, and a pole shift large enough to be possibly identified. They hope to detect the length of day signal and pole shift when Earth rotation data from ground based and space-borne position sensors are reviewed.

The researchers used data from the Harvard University Centroid Moment Tensor database that catalogs large earthquakes. The data is calculated in a set of formulas, and the results are reported and updated on a NASA Web site.

The massive earthquake off the west coast of Indonesia on December 26, 2004, registered a magnitude of nine on the new "moment" scale (modified Richter scale) that indicates the size of earthquakes. It was the fourth largest earthquake in one hundred years and largest since the 1964 Prince William Sound, Alaska earthquake.

The devastating mega thrust earthquake occurred as a result of the India and Burma plates coming together. It was caused by the release of stresses that developed as the India plate slid beneath the overriding Burma plate. The fault dislocation, or earthquake, consisted of a downward sliding of one plate relative to the overlying plate. The net effect was a slightly more compact Earth. The India plate began its descent into the mantle at the Sunda trench that lies west of the earthquake's epicenter. For information and images on the Web, visit:

The Sun Does a Flip
NASA scientists who monitor the Sun say that our star's awesome magnetic field is flipping -- a sure sign that solar maximum is here.
 
 

Listen to this story (requires RealPlayer)

February 15, 2001 -- You can't tell by looking, but scientists say the Sun has just undergone an important change. Our star's magnetic field has flipped.

The Sun's magnetic north pole, which was in the northern hemisphere just a few months ago, now points south. It's a topsy-turvy situation, but not an unexpected one.

"This always happens around the time of solar maximum," says David Hathaway, a solar physicist at the Marshall Space Flight Center. "The magnetic poles exchange places at the peak of the sunspot cycle. In fact, it's a good indication that Solar Max is really here."

 

Sign up for EXPRESS SCIENCE NEWS delivery
Above: Sunspot counts, plotted here against an x-ray image of the Sun, are nearing their maximum for the current solar cycle. [more information]

The Sun's magnetic poles will remain as they are now, with the north magnetic pole pointing through the Sun's southern hemisphere, until the year 2012 when they will reverse again. This transition happens, as far as we know, at the peak of every 11-year sunspot cycle -- like clockwork.

Earth’s magnetic field also flips, but with less regularity. Consecutive reversals are spaced 5 thousand years to 50 million years apart. The last reversal happened 740,000 years ago. Some researchers think our planet is overdue for another one, but nobody knows exactly when the next reversal might occur.

Although solar and terrestrial magnetic fields behave differently, they do have something in common: their shape. During solar minimum the Sun's field, like Earth's, resembles that of an iron bar magnet, with great closed loops near the equator and open field lines near the poles. Scientists call such a field a "dipole." The Sun's dipolar field is about as strong as a refrigerator magnet, or 50 gauss (a unit of magnetic intensity). Earth's magnetic field is 100 times weaker.

Below: The Sun's basic magnetic field, like Earth's, resembles that of a bar magnet.

When solar maximum arrives and sunspots pepper the face of the Sun, our star's magnetic field begins to change. Sunspots are places where intense magnetic loops -- hundreds of times stronger than the ambient dipole field -- poke through the photosphere.

"Meridional flows on the Sun's surface carry magnetic fields from mid-latitude sunspots to the Sun's poles," explains Hathaway. "The poles end up flipping because these flows transport south-pointing magnetic flux to the north magnetic pole, and north-pointing flux to the south magnetic pole." The dipole field steadily weakens as oppositely-directed flux accumulates at the Sun's poles until, at the height of solar maximum, the magnetic poles change polarity and begin to grow in a new direction.

Hathaway noticed the latest polar reversal in a "magnetic butterfly diagram." Using data collected by astronomers at the U.S. National Solar Observatory on Kitt Peak, he plotted the Sun's average magnetic field, day by day, as a function of solar latitude and time from 1975 through the present. The result is a sort of strip chart recording that reveals evolving magnetic patterns on the Sun's surface. "We call it a butterfly diagram," he says, "because sunspots make a pattern in this plot that looks like the wings of a butterfly."

In the butterfly diagram, pictured below, the Sun's polar fields appear as strips of uniform color near 90 degrees latitude. When the colors change (in this case from blue to yellow or vice versa) it means the polar fields have switched signs.

 

Above: In this "magnetic butterfly diagram," yellow regions are occupied by south-pointing magnetic fields; blue denotes north. At mid-latitudes the diagram is dominated by intense magnetic fields above sunspots. During the sunspot cycle, sunspots drift, on average, toward the equator -- hence the butterfly wings. The uniform blue and yellow regions near the poles reveal the orientation of the Sun's underlying dipole magnetic field. [more information]

The ongoing changes are not confined to the space immediately around our star, Hathaway added. The Sun's magnetic field envelops the entire solar system in a bubble that scientists call the "heliosphere." The heliosphere extends 50 to 100 astronomical units (AU) beyond the orbit of Pluto. Inside it is the solar system -- outside is interstellar space.

"Changes in the Sun's magnetic field are carried outward through the heliosphere by the solar wind," explains Steve Suess, another solar physicist at the Marshall Space Flight Center. "It takes about a year for disturbances to propagate all the way from the Sun to the outer bounds of the heliosphere."

Because the Sun rotates (once every 27 days) solar magnetic fields corkscrew outwards in the shape of an Archimedian spiral. Far above the poles the magnetic fields twist around like a child's Slinky toy.

Left: Steve Suess (NASA/MSFC) prepared this figure, which shows the Sun's spiraling magnetic fields from a vantage point ~100 AU from the Sun.

Because of all the twists and turns, "the impact of the field reversal on the heliosphere is complicated," says Hathaway. Sunspots are sources of intense magnetic knots that spiral outwards even as the dipole field vanishes. The heliosphere doesn't simply wink out of existence when the poles flip -- there are plenty of complex magnetic structures to fill the void.

Or so the theory goes.... Researchers have never seen the magnetic flip happen from the best possible point of view -- that is, from the top down.

But now, the unique Ulysses spacecraft may give scientists a reality check. Ulysses, an international joint venture of the European Space Agency and NASA, was launched in 1990 to observe the solar system from very high solar latitudes. Every six years the spacecraft flies 2.2 AU over the Sun's poles. No other probe travels so far above the orbital plane of the planets.

"Ulysses just passed under the Sun's south pole," says Suess, a mission co-Investigator. "Now it will loop back and fly over the north pole in the fall."

Right: Following an encounter with Jupiter in 1992, the Ulysses spacecraft went into a high polar orbit. It's maximum solar latitude is 80.2 degrees south. [more]

"This is the most important part of our mission," he says. Ulysses last flew over the Sun's poles in 1994 and 1996, during solar minimum, and the craft made several important discoveries about cosmic rays, the solar wind, and more. "Now we get to see the Sun's poles during the other extreme: Solar Max. Our data will cover a complete solar cycle."

To learn more about the Sun's changing magnetic field and how it is generated, please visit "The Solar Dynamo," a web page prepared by the NASA/Marshall solar research group. Updates from the Ulysses spacecraft may be found on the Internet from JPL at http://ulysses.jpl.nasa.gov.

Magnetic Pole Shift & Climate Change
In the past, there has been a lot of hype about the earth’s pole shift, but recently discussions on this topic have quieted.  It’s a topic that has more relevance today than ever before.  Accelerating movement in earth’s magnetic pole may be contributing to climate change here on earth.  Other bodies in our solar system may be experiencing this as well.

 

NASA illustration of earth’s magnetic field.

The last pole shift on earth is believed to have occurred 780,000 year ago.  The estimates are based on the alignment of magnetic particles within sedimentary layers and in earth’s ancient lava flows.  The effects of previous shifts on the creatures of the planet are lost to the ages.   It does appear that magnetic reversals may have been associated with major extinction events of the past.

There are several current NASA missions exploring the impact of the sun on our planet.  One interesting mission is called AIM.  It’s investigating, among other things, the cause of the changes to noctilucent clouds, the highest in our atmosphere, at our poles.  One possible cause could be our changing magnetic field.  Another mission is called, perhaps fittingly, CLUSTER, it is a joint mission with ESA aimed at better mapping our rapidly changing magnetosphere.  There are many other missions focusing on this topic of great concern.

There is evidence that poles are shifting on other bodies within our solar system which may indicate that pole shifts are a concerted event.  No one knows for sure, but it may even be a galaxy wide event caused by a change at the core of our galaxy.  Our suns poles reverse every solar cycle, the next is due, coincidentally in 2012.

 

Europa - Cassini

The effects of this shift in our magnetic field may also account for the recent changes observed in insect and bird populations.  Whether or not these animals use the magnetic field for navigation is still a hotly debated topic.  These animals do have the ability to sense and possibly even see our magnetic field and would most likely be affected to some degree by changes.

Our magnetic field protects us from the full onslaught of solar radiation.  When the magnetic field is in its normal orientation, the poles are the least protected areas.  Since the poles do not point at the sun, we remain safe.  As the poles shift, the exposed areas of the magnetic field moves closer to range of more direct solar radiation.  This has the effect of increasing the amount of solar radiation that reaches the surface.  Some have even suggested that the sun’s rays will roast us as the poles flip.

 

 

Solar Flare - NASA - TRACE

As the normally protected areas become exposed to solar radiation, it has the effect of heating different areas of the planet and altering our normal weather patterns.  We are seeing the effects of this now, some areas of the planet are warming and some are cooling.  Record highs and lows are being broken across the surface of the earth.

Government or governments aware of this cause and effect could use this information to their advantage.  Recently it was learned that our government is contemplating the creation of yet another agency, a climate change agency.  Our government is currently assigning the cause of climate change to us and our cars.  As time goes by, the effects of increasing solar radiation through our weakened magnetic field will cause more climate change.  This will reinforce the position held by the government that our climate will worsen and that we are the cause.

 

NOAA - Storm

It will get worse and there is no way to stop it.  As the poles shift not only does is expose areas of the earth that are normally protected, it also weakens the entire magnetic field exposing more of the planet to sun’s wrath.  Of course this will have a dramatic effect on our weather and the impact on us is going to get worse, much worse.  You can park your car and ride the bus and it will have very little effect.

The sad ending to it all is the fact that there really is nothing we can do about it.  We can only brace for what may indeed be a wild ride.  We can hope that the effects are manageable, allowing us to survive the shift.  Perhaps we can take steps to prepare for the worst by having a plan to escape from the effects.  There is no amount of new government, laws or taxes that can stop our magnetic poles from shifting.  In the end we are at the mercy of our planet and our sun.

Something beneath the surface is changing Earth's protective magnetic field, which may leave satellites and other space assets vulnerable to high-energy radiation.

The gradual weakening of the overall magnetic field can take hundreds and even thousands of years. But smaller, more rapid fluctuations within months may leave satellites unprotected and catch scientists off guard, new research finds.

A new model uses satellite data from the past nine years to show how sudden fluid motions within the Earth's core can alter the magnetic envelope around our planet. This represents the first time that researchers have been able to detect such rapid magnetic field changes taking place over just a few months.

"There are these changes in the South Atlantic, an area where the magnetic field has the smallest envelope at one third [of what is] normal," said Mioara Mandea, a geophysicist at the GFZ German Research Center for Geosciences in Potsdam, Germany.

Even before the newly detected changes, the South Atlantic Anomaly represented a weak spot in the magnetic field — a dent in Earth's protective bubble.

Bubble bobble

The Earth's magnetic field extends about 36,000 miles (58,000 km) into space, generated from the spinning effect of the electrically-conductive core that acts something like a giant electromagnet. The field creates a tear-drop shaped bubble that has constantly shielded life on Earth against much of the high-energy radiation flowing from the sun.

The last major change in the field took place some 780,000 years ago during a magnetic reversal, although such reversals seem to occur more often on average. A flip in the north and south poles typically involves a weakening in the magnetic field, followed by a period of rapid recovery and reorganization of opposite polarity.

Some studies in recent years have suggested the next reversal might be imminent, but the jury is out on that question.

Measuring interactions between the magnetic field and the molten iron core 1,864 miles (3,000 km) down has proven difficult in the past, but the constant observations of satellites such as CHAMP and Orsted have begun to bring the picture into focus.

Electric storm

Mandea worked with Nils Olsen, a geophysicist at the University of Copenhagen in Denmark, to create a model of the fluid core that fits with the magnetic field changes detected by the satellites.

However, the rapid weakening of the magnetic field in the South Atlantic Anomaly region could signal future troubles for such satellites. Radiation storms from the sun could fry electronic equipment on satellites that suddenly lacked the protective cover of a rapidly changing magnetic field.

"For satellites, this could be a problem," Mandea told SPACE.com. "If there are magnetic storms and high-energy particles coming from the sun, the satellites could be affected and their connections could be lost."

The constant radiation bombardment from the sun blows with the solar wind to Earth, where it flows against and around the magnetic field. The effect creates the tear-drop shaped magnetosphere bubble, but even the powerful field cannot keep out all the high-energy particles.

Topsy-turvy history

A large sunspot set off a major radiation storm in 2006 that temporarily blinded some sun-watching satellites. Astronauts on the International Space Station retreated to a protected area as a precaution to avoid unnecessary radiation exposure.

The Earth's overall magnetic field has weakened at least 10 percent over the past 150 years, which could also point to an upcoming field reversal.