Big Earthquakes Create Global-Scale GPS Errors
2013-05-28 0:00

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

Facebook completes first drone flight above UK, Mark Zuckerberg confirms
2015-03-28 3:15
Solar powered drones which provide internet access to rural and remote areas have been trialled in UK for first time by Facebook. They “have a wingspan greater than a Boeing 737 but will weigh less than a car”, according to the social network's chief Mark Zuckerberg. The drones, developed by Somerset-based company Ascenta which Facebook bought last March, will beam down laser-guided ...
300 Young English Girls (and a few Boys) Groomed and Assaulted by Oxfordshire "Gangs," Report Finds
2015-03-28 2:04
Editor's note: This story is a few days old now but the echoes of Rotherham just keeps coming. A few weeks ago there was Halifax, now Britain proudly can add Oxfordshire to their line up of diversity success stories. Below is the story from the telegraph: Serious case review finds failings by police and social services as it identifies hundreds of victims A ...
British POW describes the horror of the bombing of Dresden
2015-03-28 0:33
Partial Transcript of Interview with Victor Gregg, WW2 British solder and POW: Interviewer: "Tell us how it was that you were in Dresden at that time." Victor Gregg: "It was evil....thousands of firebombs dropping all over the place, heat, fire, people screaming, people burning, people alight. After about half an hour it started developing into something that was really bad....It was ...
Rape of 285,000 German Women at the End of WWII Trigger Damage Control by Mainstream Media
2015-03-27 20:25
Is Exposing Allied War Crimes an honorable act? No, it’s slandering heroes according to Daily Mail A recent article from the Daily Mail that pretends to look at the post WWII crimes and rapes of the Allies against the German people is actually damage control. It’s really an attempt to divert away from the true horrors that was visited upon Germany ...
Minister of Migration attacked by asylum seeker with fire extinguisher
2015-03-27 2:12
Sweden’s Minister of Justice & Migration also known as Morgan “only 1%” Johansson, has been attacked with a fire extinguisher when he visited an asylum home for future Swedes. Regional newspaper, Kristiandstadsbladet reported that a man who had been living at the home for a couple of weeks grabbed a fire extinguisher and sprayed foam all over the minister who didn’t ...
More News »