Straddling the equator and engaged in a titanic clash
of great tectonic plates, South America is home to some of
the world’s most scenic landscapes. Yet this same proximity
to the equator, with its frequent tropical cloud cover, has
also made it difficult to obtain traditional satellite
imagery of this vast land.

Thanks to cloud-penetrating radar flown on NASA’s Shuttle
Radar Topography Mission (SRTM), Feb. 11 – 22, 2000, more
than 340 million residents of the fourth largest continent
have access to the same level of high-resolution topographic
data North America and much of Europe have taken for
granted. A just released topographic data set sheds fresh
light on the diverse characteristics of South America and
paves the way for a wide variety of scientific
investigations and commercial applications.

“These data, and previously released data, continue to
demonstrate the extraordinary value space-based radar can
provide for better understanding and protecting our home
planet,” said Dr. Ghassem Asrar, Associate Administrator for
Earth Sciences, NASA Headquarters, Washington. “This
information has scientific and commercial value that will
help to improve life here, and provides new understanding of
how South America has evolved through time.”

“These new data highlight the tremendous diversity of South
America’s geology as never before,” said Dr. Michael
Kobrick, SRTM project scientist at NASA’s Jet Propulsion
Laboratory (JPL), Pasadena, Calif. “The improved resolution
of this data set will make a tangible difference in the
lives of people throughout the continent in many ways. For
example, governments may be better able to prepare for
natural hazards such as earthquakes, volcanic eruptions,
landslides and floods; aviation safety in mountainous
regions may be improved; and land use planners will be able
to make better decisions regarding the development of
critical infrastructure such as roads, reservoirs, aqueducts
and communications,” Kobrick said.

At 17,819,000 square kilometers (6,879,954 square miles),
South America accounts for approximately 12 percent of
Earth’s land mass. Its topography is dominated by the Andes
Mountains, which extend along the Pacific Coast. The Andes
were created primarily by the convergence of the Nazca and
South American tectonic plates. The Nazca Plate, which
underlies the eastern Pacific Ocean, slides under western
South America, resulting in crustal thickening, uplift and
volcanism. Another convergence zone is found along the
continent’s northwestern coast, where the Caribbean Plate
also slides under the South American Plate, forming the
northeastern extension of the Andes.

East of the Andes, much of northern South America drains
into the Amazon River, the world’s largest river in terms of
both watershed area and flow volume. Topographic relief is
very low in much of the Amazon Basin, but the new data
provide a detailed look at the basin’s 3-Dimensional
drainage pattern. North of the Amazon, the Guiana Highlands
stands in sharp contrast to the surrounding lowlands. South
of the Amazon, the Brazilian Highlands show a mix of
landforms. Fractures paralleling the east coast are likely
related to the opening of the Atlantic Ocean as South
America drifted away from Africa, starting about 130 million
years ago.

Two visualization methods were combined to produce the main
South America image: shading and color coding of topographic
height. The shade image was derived by computing topographic
slope in the northwest-southeast direction, so northwest
slopes appear bright and southeast slopes appear dark.
Color-coding depicts the lowest elevations in green, rising
through yellow and tan, to white at the highest elevations.

The SRTM made 3-D measurements of more than 80 percent of
Earth’s landmass, located between 60 degrees north and 56
degrees south of the equator. The mission is a cooperative
project of NASA, the National Imagery and Mapping Agency of
the U.S. Department of Defense, the German and Italian space
agencies. The mission continues to fulfill NASA’s mission to
understand and protect our home planet.

Selected images created from the data set are available on
the JPL Planetary Photojournal:

Information about SRTM is available on the Internet at:
http://www.jpl.nasa.gov/srtm/

Information about NASA is available on the Internet at:
http://www.nasa.gov