Gravity imaging highlights structures beneath the seafloor sediments because variations in mass (as in hills and valleys) cause variations in the gravity field above them. In this image, buried fracture zones can be clearly traced where thick sediments make them invisible in the surface topography.
Species (common):
Year: 2008
Details: Gravity
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
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Investigator: MGDS
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The unusual pattern is formed by shallow wetlands that are prime habitat for some of China's endangered cranes, such as the Red-crowned Crane. Signs of human activity, such as fields and roads or railways are visible here.
Species (common):
Year: 2008
Details: Asia
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
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Investigator: MGDS
Expedition:
Chief Scientist:
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Volcanoes often occur at subduction zones, like these at the boundary of the Pacific and Eurasian plates on the Kamchatka peninsula in far eastern Siberia. The central volcano in the image appears to have a new, double cone forming in the center of the huge caldera of an older volcano.
Species (common):
Year: 2008
Details: Asia
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
Feature:
Investigator: MGDS
Expedition:
Chief Scientist:
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The delta of the Mekong River, in southernmost Vietnam, is an important rice-growing area for Vietnam and home to twenty million people. Traces of the rice fields and roads can be seen.
Species (common):
Year: 2008
Details: Asia
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
Feature:
Investigator: MGDS
Expedition:
Chief Scientist:
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River meanders are clearly seen here, as well as oxbow lakes formed when the river changed direction. Signs of human activity, such as road and railway clearings alongside the tributary stream, are visible as cuts in the tree canopy.
Species (common):
Year: 2008
Details: Asia
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
Feature:
Investigator: MGDS
Expedition:
Chief Scientist:
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This image shows sand dunes in the Taklamakan desert, the largest desert in central Asia and one of the largest sandy deserts in the world. Most of the dunes shown here are linear dunes, which form when sand is blown by winds which alternate in direction, often seasonally. This causes them to develop a meandering form and grow in length, unlike Barchan dunes, which form crescent shapes which can move across the landscape. Barchan dunes are formed when there is a single dominant wind direction.
Species (common):
Year: 2008
Details: Asia
Media Type: Map
Data Type: Bathymetry

This image shows the "Mouths of the Ganges", branches of the Ganges River, entering the Bay of Bengal. Traces of human agricultural activities, probably trees bordering farmed areas and drainage ditches can also be seen.
Species (common):
Year: 2008
Details: Asia
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
Feature:
Investigator: MGDS
Expedition:
Chief Scientist:
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The relatively flat-lying rock layers are highlighted by erosion, possibly caused by wind-blown sand from the nearby Sahara desert.
Species (common):
Year: 2008
Details: Africa
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
Feature:
Investigator: MGDS
Expedition:
Chief Scientist:
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This image depicts a bullseye structure, the Richat structure, in Mauritania. It was first noticed by space shuttle crews because of its prominent multiple ring features. The structure has a diameter of almost 50 km and was initially interpreted as an impact crater (a feature formed by the impact of a meteorite with Earth). However, so far no evidence has been found to support this interpretation (shock features or any other evidence).

This image is the Wau en Namus volcano in the middle of the Sahara desert of south-central Libya. Three small salt lakes on the floor of the caldera have contributed to the name, which means 'oasis of mosquitoes'. The cone is about 500 m high, 4km in diameter, and surrounded by an apron of black volcanic ash 5-10km wide. There are several websites showing photos of this remarkable spot. Another volcanic structure is visible to the northwest.
Species (common):
Year: 2008
Details: Africa
Media Type: Map
Data Type: Bathymetry
Device Type: Sonar:Multibeam
Feature:
Investigator: MGDS