Sydney: Investigators searching for the missing Malaysia Airlines plane in the remote southern Indian Ocean have released detailed images of the seabed - revealing features such as extinct volcanoes and 1,400-metre depressions for the first time.
The collection of data from one of the most secret parts of the world is a by-product of the search for the Boeing 777 plane which went missing from the Malaysian capital, Kuala Lumpur, to Beijing on March 8 along with 239 people, including five Indians, on board.
Until now there were better maps of Mars than of this bit of the sea floor, the BBC reported.
Twenty-six countries have helped look for the plane, but nothing has ever been found.
The team at the Australian Transport Safety Bureau (ATSB), which is leading the hunt for the plane, is using sonar to map the new "priority" search area, at the bottom of the southern Indian Ocean off the coast of Western Australia.
After that they will deploy two or three deep sea vehicles to begin the painstaking, inch-by-inch seabed search for wreckage.
The "priority" area of 60,000 square kilometres is based on the only piece of hard evidence investigators have, which is a series of brief, electronic "hellos" between the Boeing and a satellite.
Making sonar maps is vital to ensure the team does not crash its deep-water vehicles into ridges and volcanoes. The equipment is pulled along just above the sea floor by a 10km- long armoured cable.
Snagging that cable could damage the kit, or even cut it free, so the maps help them avoid any obstructions.
The deep sea search vehicles have sonar that can pick out odd lumps, cameras that can double check if that lump is wreckage or just a rock and an electronic nose that can smell aviation fuel in the water, even if it is heavily diluted.
The operation to find flight MH370 is the most complex search in history. They may find clues within months. Or they may never find the aircraft.
Malaysia believes the plane was deliberately diverted by someone on board.
Investigators, including the FBI, are looking into a range of aspects, including hijack, sabotage, personal and psychological problems, that may have caused the incident.