A thin 'soft' layer, made from partially molten rocks, has been discovered within the Earth's mantle, more extensive than previously thought.
This sort of bearing that could play a crucial role in plate movements was identified by a research team led by Junlin Hua, of the University of Texas at Austin, and published in Nature Geoscience.
“With a great approximation we can think of the outermost layers of the planet as blocks of ice, the plates, which rest and slide on a layer of water.
Obviously it is not water but rock, and the 'liquid' layer is not actually liquid but the same rock material but slightly more fluid”, explained the Head of the Center for Monitoring Subsoil Activities of the National Institute of geophysics and volcanology (Ingv), Andrea Morelli.
It has long been believed that in the mantle, the layer immediately under the earth's crust, there is the so-called asthenosphere, i.e. a sort of 'soft' cushion on which large portions of the planet's 'clods' rest and whose slow movements are then the origin of the more superficial movements.
But the existence of this soft layer, called the asthenosphere,
it was hitherto limited to a few areas and it had not so far been possible to recognize the signs of its presence in deeper areas.
Now, by analyzing the transmission of seismic waves across the planet and combining these data with models on the characteristics of the rocks at the very high temperatures and pressures generated on the planet, it has been possible to recognize the presence of the asthenosphere even at depths between 100 and 200 kilometers from the surface.
“It is an interesting work – added Morelli – because it brings together many different types of observations and makes an important contribution to understanding the dynamics of the depths of the planet.
There are still many uncertainties as to why the mantle assumes those viscosity characteristics under certain conditions, but we certainly now have important new data".
Now, by analyzing the transmission of seismic waves across the planet and combining these data with models on the characteristics of the rocks at the very high temperatures and pressures generated on the planet, it has been possible to recognize the presence of the asthenosphere even at depths between 100 and 200 kilometers from the surface.
“It is an interesting work – added Morelli – because it brings together many different types of observations and makes an important contribution to understanding the dynamics of the depths of the planet.
There are still many uncertainties as to why the mantle assumes those viscosity characteristics under certain conditions, but we certainly now have important new data".
Now, by analyzing the transmission of seismic waves across the planet and combining these data with models on the characteristics of the rocks at the very high temperatures and pressures generated on the planet, it has been possible to recognize the presence of the asthenosphere even at depths between 100 and 200 kilometers from the surface.
“It is an interesting work – added Morelli – because it brings together many different types of observations and makes an important contribution to understanding the dynamics of the depths of the planet.
There are still many uncertainties as to why the mantle assumes those viscosity characteristics under certain conditions, but we certainly now have important new data".
analyzing the transmission of seismic waves across the planet and combining these data with models on the characteristics of the rocks at the very high temperatures and pressures generated on the planet, it was possible to recognize the presence of the asthenosphere even at depths between 100 and 200 kilometers from the surface .
“It is an interesting work – added Morelli – because it brings together many different types of observations and makes an important contribution to understanding the dynamics of the depths of the planet.
There are still many uncertainties as to why the mantle assumes those viscosity characteristics under certain conditions, but we certainly now have important new data".
analyzing the transmission of seismic waves across the planet and combining these data with models on the characteristics of the rocks at the very high temperatures and pressures generated on the planet, it was possible to recognize the presence of the asthenosphere even at depths between 100 and 200 kilometers from the surface .
“It is an interesting work – added Morelli – because it brings together many different types of observations and makes an important contribution to understanding the dynamics of the depths of the planet.
There are still many uncertainties as to why the mantle assumes those viscosity characteristics under certain conditions, but we certainly now have important new data".
it was possible to recognize the presence of the asthenosphere even at depths between 100 and 200 kilometers from the surface.
“It is an interesting work – added Morelli – because it brings together many different types of observations and makes an important contribution to understanding the dynamics of the depths of the planet.
There are still many uncertainties as to why the mantle assumes those viscosity characteristics under certain conditions, but we certainly now have important new data".
it was possible to recognize the presence of the asthenosphere even at depths between 100 and 200 kilometers from the surface.
“It is an interesting work – added Morelli – because it brings together many different types of observations and makes an important contribution to understanding the dynamics of the depths of the planet.
There are still many uncertainties as to why the mantle assumes those viscosity characteristics under certain conditions, but we certainly now have important new data".