YOU ARE HERE: Home > News & Press > News archive > News 2007 > RAS PN 07/47 (forwarded): Hills and valleys in Earth's largest 'salt flat'

I want information on:

Information for:


RAS PN 07/47 (forwarded): Hills and valleys in Earth's largest 'salt flat'

Last Updated on Wednesday, 07 April 2010 13:46
Published on Thursday, 29 November 2007 00:00
A team of scientists have found that Earth's largest salt 'flat', the salar de Uyuni in Bolivia, is rougher than expected...

Date:  29 November 2007           For Immediate Release
Ref.: PN 07/47 (forwarded)
Issued by RAS Press Officer:
Dr Robert Massey
Tel: +44 (0)20 7734 4582      
Mobile: +44 (0)794 124 8035
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

RAS website:


Using a new twist on standard Global Positioning System (GPS) technology, a team of scientists has found that Earth’s largest salt flat is rougher than expected, according to a new report led by Adrian Borsa of Scripps Institution of Oceanography at UC San Diego and published in Geophysical Journal International.

Borsa and his team studied the salar de Uyuni in southwestern Bolivia, which is both a popular tourist destination and a potential calibration site for Earth-orbiting scientific instruments. It had never before been surveyed on this scale using modern techniques.  Although the salar appears to be perfectly flat to the eye, by applying an innovative method of error correction to their data, the team was able to identify broad features ranging in height from a few centimeters to half a meter and extending over distances of tens of kilometers or more.

Earlier maps do not show any surface relief on the salar de Uyuni.  By mapping the surface to the accuracy of a few centimeters, the research team uncovered previously hidden features -- hills, ridges and valleys -- and opened the salar for use as a ground reference site for highly accurate satellite-based ranging instruments.  “We had no idea these features existed,” said Dr. Borsa, “but they matter to anyone who uses the salt flat to calibrate satellite altimeters.” 

The scientists' most unexpected finding was that the broadest topographic features on the salar correlate well with the increase in the strength of gravity at the surface that results from dense rock buried underneath salar sediments.  Just as the ocean surface rises over denser seamounts, the salar surface also rises and falls to reflect the subsurface density variations. This effect has never before been observed on land.


Maps, images and PDFs of the full article are available from

Samantha Holford
9600 Garsington Road
Oxford OX4 2DQ
Tel: +44 (0)1865 476269
Fax: +44 (0)1865 471269
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.


The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy and geophysics nationally and internationally. Its more than 3000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

Published jointly by the RAS and the Deutsche Geophyiskalische Gesellschaft, Geophysical Journal International is one of the world's leading primary research journals in geophysics.