The underwater search for the missing Malaysia Airlines MH370 has become focused on the Zenith Plateau in the eastern Indian Ocean, lying about 1000 km to its nearest point on the Western Australia coast, or 1685 km north-west of Perth. The plateau is surrounded by the extensive Wharton Basin to the west and north, joins to the Quokka Rise and Wallaby (or Cuvier) Plateau to the east, and is bounded to the south by the Perth Abyssal Plain.
The origin of this plateau is proposed to be a fragment of continental crust that started rifting from the western Australian margin during the break-up of Gondwana in the Early Cretaceous. The northward migration of India away from Australia resulted in extinct spreading ridges and volcanoes that blanketed the region in volcanic deposits by the Late Cretaceous. Subsequent drowning of the plateau in the Cenozoic has resulted in a thick build-up of calcareous ooze that now forms the present day seafloor.
The Zenith Plateau has a dimension of about 330 km wide in the east-west direction and about 220 km in the north-south direction. The plateau is relatively deep with its shallowest point at 1670 m and gently deepening towards the Wharton Basin in north at around 5000 m. The Wallaby-Zenith Fracture Zone forms an escarpment along the southern margin of the plateau with a steep drop of between 2000 to 3000 m into a narrow trough with depths close to 6000 m. This narrow trough separates the Zenith Plateau from the adjacent Perth Abyssal Plain to the south.
The plateau is very poorly mapped with no modern multibeam surveys anywhere over this feature. Our current understanding of the bathymetry (or depth) of the plateau are therefore based on older singlebeam echosounder data and coarse satellite gravity data. Within the current MH370 underwater search area on the northern flank of the plateau, seafloor depths range from about 4400 to 4600 m. The finer-scale seafloor topography in the search zone appears to undulate, varying by up to 300 m in height over distances of approximately 24 km, but cannot be confirmed with the coarse bathymetry data available.
A Google Earth KMZ file of the latest hillshaded digital elevation model (DEM) of the Zenith Plateau is available below. This DEM incorporates all the available source bathymetry data for the region.
View Search area 14 Apr 2014 in a larger map