Mapping the Moho with GOCE

Mar 09, 2012

The first global high-resolution map of the boundary between Earth's crust and mantle – the Moho – has been produced based on data from ESA's GOCE gravity satellite. Understanding the Moho will offer new clues into the dynamics of Earth's interior.

Earth's crust is the outermost solid shell of our planet. Even though it makes up less than 1% of the volume of the planet, the crust is exceptionally important not just because we live on it, but because is the place where all our geological resources like natural gas, oil and minerals come from. The crust and upper mantle is also the place where most geological processes of great importance occur, such as earthquakes, volcanism and orogeny.

Until just a century ago, we didn't know has a crust. In 1909, Croatian seismologist Andrija Mohorovičić found that at about 50 km underground there is a sudden change in seismic speed.

Ever since, that boundary between Earth's crust and underlying mantle has been known as the Mohorovičić discontinuity, or Moho.

Even today, almost all we know about Earth's deep layers comes from two methods: seismic and gravimetric.

Seismic methods are based on observing changes in the propagation velocity of seismic waves between the crust and mantle.

Gravimetry looks at the gravitational effect due to the density difference caused by the changing composition of crust and mantle.

But the Moho models based on seismic or gravity data are usually limited by poor data coverage or data being only available along single profiles.

The GOCE Exploitation for Moho Modelling and Applications project – or GEMMA – has now generated the first global high-resolution map of the boundary between Earth's crust and based on data from the GOCE satellite.

GOCE measures the gravity field and models the geoid with unprecedented accuracy to advance our knowledge of ocean circulation, which plays a crucial role in energy exchanges around the globe, sea-level change and Earth interior processes.

GEMMA's Moho is based on the inversion of homogenous well-distributed gravimetric data.

For the first time, it is possible to estimate the Moho depth worldwide with unprecedented resolution, as well as in areas where ground data are not available. This will offer new clues for understanding the dynamics of Earth's interior, unmasking the gravitational signal produced by unknown and irregular subsurface density distribution.

GEMMA is being carried out by Italian scientist Daniele Sampietro, and is funded by the Politecnico di Milano and ESA's Support To Science Element under the Changing Earth Science Network initiative.

This initiative supports young scientists at post-doctoral level in ESA Member States to advance our knowledge in Earth system science by exploiting the observational capacity of ESA missions.

Explore further: Thousands of intense earthquakes rock Iceland

add to favorites email to friend print save as pdf

Related Stories

Hot Fluids and Deep Earthquakes

May 08, 2007

Fluids in the Earth's lower crust are an underlying force in shaking things up where continental plates slip under each other, according to a study recently published in Nature. Donna Eberhart-Phillips, a UC Davis researcher ...

Recommended for you

NASA sees Depression 12-E become Tropical Storm Lowell

15 hours ago

In less than 24 hours after Tropical Depression 12-E was born in the eastern Pacific Ocean it strengthened into Tropical Storm Lowell. NOAA's GOES-West and NASA's Aqua satellite captured infrared images of ...

Why global warming is taking a break

16 hours ago

The average temperature on Earth has barely risen over the past 16 years. ETH researchers have now found out why. And they believe that global warming is likely to continue again soon.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

GreyLensman
5 / 5 (2) Mar 09, 2012
Great. An article abouot a map, with no map. Kudos.
yyz
not rated yet Mar 09, 2012
"An article abouot a map, with no map"

A link to GOCE's Moho maps: http://www.esa.in...x_1.html