Big Earthquakes Create Global-Scale GPS Errors
2013 05 28

By Becky Oskin | LiveScience

Thirteen years of supersized earthquakes, such as today’s (May 24) magnitude-8.3 in Russia, have contaminated GPS sites around the world, a new study finds.

The Global Positioning System is a network of satellites and ground stations that provide location information anywhere on Earth. Except for spots in Australia, western Europe and the eastern tip of Canada, every GPS site on the ground underwent small but important shifts since 2000 because of big earthquakes, according to a study published May 6 in the Journal of Geophysical Research: Solid Earth.

The research confirms that great earthquakes, those bigger than magnitude 8.0, can have far-reaching effects on the Earth’s crust. And because GPS is critical for everything from calculating satellite orbits to sea level rise to earthquake hazards, scientists can’t ignore these tiny zigs and zags, the researchers conclude.

"We have to find a way to deal with it," said Paul Tregoning, lead study author and a geophysicist at Australia National University in Canberra. "The community needs to work out how to find all the offsets, estimate them accurately and get everyone to agree on how to correct them," he told LiveScience.


Deformation from earthquakes bigger than magnitude 8.0 since 2000. The blue squares are GPS reference sites, and the red arrows are deformation from big earthquakes.

Tregoning and his colleagues modeled the sudden jolts in Earth’s crust from each of the 15 biggest earthquakes since 2000. They discovered that crust thousands of miles away from the faults had moved horizontally by as much as a tenth of an inch (a few millimeters). The model was checked against a few spots around the planet. On average, the earthquakes deformed the crust by a hundredth of an inch every year (0.4 millimeters a year) — about the width of the lead in a mechanical pencil.

"It’s quite amazing to us that we can see this and detect this," Tregoning said.

These tiny effects won’t make a difference to the GPS in cars or phones, or the tough little units carried by hikers and mountaineers. But scientists who need precise measurements to calculate sea level rise or satellite orbits should be concerned, Tregoning said.

The changing Earth

Here’s why these seemingly small changes matter. Scientists who rely on GPS need to compare one place to another. There are a handful of stable spots around the world, usually in the interior of continents, called the terrestrial reference frame. For example, a geologist measuring the speed of the Pacific plate would compare it with the North American reference frame. But Tregoning’s study shows these stable spots were shifted by the massive earthquakes.

Disturbing the reference frame will introduce errors into GPS measurements, Tregoning said. It could also throw off calculations of satellite orbits. "If the coordinates of the tracking stations are wrong, then the orbit isn’t right either," he said.

[...]

Read the full article at: livescience.com




Related Articles
U.S. weather-watcher satellite fails just before hurricane season
Big Earthquakes Might Calm the Earth
Ripples From Japan Earthquake Felt In Space
Earthquakes turn water into gold
Stunning Map Reveals World’s Earthquakes Since 1898
Earthquakes have a bigger health toll than other disasters
US Government Takes Down HAARP Website to Conceal Evidence of US Weather Modification and Earthquake Inducing Warfare
HAARP Creates Artificial Aurora, Lights Up The Sky


Latest News from our Front Page

Norway Joins the Race to Develop Killer Robots
2014 10 24
Norway is a large exporter of weapons, which makes the resolution of the debate about creating killer robots an important issue for everyone.  One could debate the overall merits or failings of robotic systems, but an area that clearly has become a point for concern on all sides is the emergence of "killer robots." According to robotics pioneer, David Hanson, ...
Gene That Once Aided Survival in the Arctic Found to Have Negative Impact on Health Today
2014 10 23
In individuals living in the Arctic, researchers have discovered a gene variant that arose thousands of years ago and most likely provided an evolutionary advantage for processing high-fat diets or for surviving in a cold environment; however, the variant also seems to increase the risk of hypoglycemia, or low blood sugar, and infant mortality in today’s northern populations. {snip} “Our work ...
The Ebola hoax: questions, answers, and the false belief in the “One It”
2014 10 23
“The Reality Manufacturing Company doesn’t just sell ‘fake paintings’ that are easy to spot. No. They also sell images that are geared to mesh with people’s deeply held instincts and thereby produce rigid false beliefs. People are sure that if they gave up such beliefs, their world would fall apart and blow away in the wind.” ...
New Controversial Theory Suggests "Hobbits" Were Not Human - Who Were These Mysterious Beings?
2014 10 23
The origin of the Hobbit species remains a challenging subject to scientists. The Hobbit’s discovery confirmed the view that the Earth was once populated by many species of human, but new research the Hobbit’s were not human at all! So, who were these mysterious beings? Where did they come from? The idea that our species, Homo sapiens, was the only species of human on ...
Right into enemy hands? ISIS shows off new weapons allegedly airdropped by US (VIDEO)
2014 10 23
Islamic State has published a new video in which a jihadist shows off brand-new American hardware, which was purportedly intended for the Kurds they are fighting in the Syrian border town of Kobani. The undated video, posted by the unofficial IS mouthpiece “a3maq news”, sees a jihadist showing several boxes of munitions with English-language markings, with a parachute spread out on ...
More News »