Did you know that oceans cover two thirds of the planet, but only ~10% has been mapped?

For example, Malaysian airlines flight MH370 was lost in 2014 in the Indian Ocean, west of Australia, where it is almost completely uncharted.

Therefore, a more rapid method of mapping the ocean is needed.

Here, 2 satellites were used to map the ocean floor (CryoSat-2, Jason-1).

They mapped ~5,000 sea-mountains taller than 2 km (about the size of Australia’s tallest mountain Mt. Kosciuszko).

They also discovered a long ridge (800 x 100 km) along the coast of Africa that was paired with a mirror image fault line off the coast of South America.

Mapping the ocean floor is important for understanding plate tectonics, the geological history of Earth, shipping/transport routes, management of fisheries and for understanding ocean currents that influence the climate.

Do you want more information?

Background

Oceans cover two thirds of the planet, but ~90% has not been mapped.

For example, Malaysian airlines flight MH370 was lost in 2014 in the Indian Ocean, west of Australia, where it is almost completely uncharted.

Mapping the ocean floor is usually performed by large research ships using echosounders. Hundreds of ships working for the past 40 years have barely covered ~10% of the ocean floor.

Therefore, a more rapid method is required.

Sediment from the continents can flow hundreds to thousands of kilometres across the ocean floor, making it appear flat and featureless. However, below it, the rock bed can have huge peaks and troughs.

Here, satellites were used to map the ocean floor.

Materials and Methods

A team of scientists from California and the University of NSW (and other places) analysed radar data from 2 satellites (CryoSat-2 and Jason-1) to map the ocean floor. They analysed >70 months of data. They map the ocean floor from the shape of the water surface above it. Water is affected by gravity, so it is pulled into highs above sea-mountains and slumps low over depressions (e.g. trenches), thereby affecting its shape.

Results

The satellites mapped ~5,000 sea-mountains taller than 2 km (about the same size as Australia’s highest peak Mt. Kosciusko).

They also discovered a new pair of tectonic features: a long ridge (800 x 100 km) along the coast of Africa, with a mirror image fault line off the cost of South America. That is, newly discovered plate tectonic features.

Discussion

Mapping the ocean floor is important for understanding plate tectonics, the geological history of Earth, shipping/transport routes, management of fisheries (animals congregate around sea-mountains), and for understanding large ocean currents that influence global climates.

Article

New global marine gravity model from CryoSat-2 and Jason-1 reveals buried tectonic structure

Sandwell et al., 2014 Science 346:65-7

Keywords

Ocean, floor, geology, Earth, satellite, mapping, map, tectonic, plates, ridge, continent, mountain, gravity, fault, peak

Subject

Science, Earth and Space, Geology, ST1-8ES, ACSSU019, ST2-8ES, ACSSU075, ST3-9ES, ACSSU096, SC4-12ES, ACSSU153, SC4-13ES, ACSSU222, SC5-13ES, ACSSU180, ACSSU189