‘Speed gun’ for Earth’s insides developed

Thursday, October 28, 2010

LONDON - University of Bristol’s scientists have claimed that they have developed a seismological ’speed gun’ for the inside of the Earth and this technique will enable them to measure the way the Earth’s deep interior slowly moves around.

The mantle motion is what controls the location of our continents and oceans, and where the tectonic plates collide to shake the surface we live on.

For 2,900 km beneath our feet, the Earth is made of the rocky mantle. Although solid, it is so hot that it can flow like putty over millions of years. It is heated from below, so that it circulates like water on a stove.

While geophysicists know something about how the material moves by the time it reaches the top of the mantle, what goes on at the bottom is still a puzzle.

“The only way to measure the inside of the Earth at such huge depths is with seismic waves. When a large earthquake occurs and waves travel through the Earth, they are affected in different ways, and we can examine their properties to work out what is happening thousands of miles beneath our feet, a region where we can never go,” said Andy Nowacki from the School of Earth Sciences at Bristol University.

“This study focusses on a mysterious layer where the mantle meets the core, a sphere of iron at the centre of the Earth 7,000 km across. This part just above the core has curious properties which we can measure using seismic waves that pass through it,” he added.

Professor Mike Kendall added that, “this part of the Earth is incredibly important. The lowermost mantle is where two colossal, churning engines-the mantle and the core-meet and interact. The core is moving very quickly and creates our magnetic field, which protects us from the Sun’s rays. The mantle above is sluggish, but drives the motion of the plates on the Earth’s surface, which builds mountains, feed volcanoes and cause earthquakes. Measuring the flow in the lowermost mantle is vital to understanding the long term evolution of the Earth.”

The study has been published in the journal Nature. (ANI)

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