PERTH, Australia -- Recovery teams face a treacherous journey through rolling seas to a largely uncharted ocean floor scarred by a volcanic ridge - even if investigators can pinpoint where Flight MH370 crashed, experts warned Wednesday.
An area the size of Alaska is being searched by planes and ships in the hunt for debris that could lead to the wreckage of the Malaysia Airlines Boeing 777.
Despite an array of military-grade technology, much of the searching is being carried out using the human eye – a task that one security intelligence analysis firm described as “immensely difficult.”
“The expression 'like finding a needle in a haystack' shouldn’t be used to describe [search-and-rescue] and recovery at sea,” the Soufan Group wrote in a briefing. “A more accurate expression would be like finding a drifting needle in a chaotic, color-changing, perception-shifting, motion-sickness-inducing haystack.”
A new set of satellite images was released Wednesday showing 122 “potential objects” in the remote corner of the southern Indian Ocean where possible debris was previously spotted.
Locating the debris field is only the first challenge for investigators who are racing against time to locate the “black boxes” – the flight data record and cockpit voice recorder – which could solve the mystery of why MH370 flew thousands of miles in the wrong direction, leading to the assumed deaths of all 239 on board.
Among the potential hazards is a huge line of underwater volcanoes whose magma is constantly reshaping the sea floor almost a two miles below the surface.
The Southeast Indian Ridge – marking the boundary between the Antarctic and Australasian tectonic plates - runs along the floor of the Indian Ocean, ending about 110 miles from where Chinese satellites spotted a large potential object. If debris has drifted, it means could Flight MH370 could lie in a gully along the complex terrain of the ridge, hidden from recovery crews.
"It's very unfortunate if that debris has landed on the active crest area, it will make life more challenging," Robin Beaman, a specialist in underwater geology at Queensland's James Cook University, told AFP.
"It's rugged, it's covered in faults, fine-scale gullies and ridges, there isn't a lot of sediment blanketing that part of the world,” he said.
That could make the search for MH370’s black boxes even harder than the hunt for AF447, the Air France flight whose fuselage was found on a flat part the Atlantic Ocean floor two years after it crashed in 2009.
However, one expert told NBC News that the other satellite images put the possible debris field a significant distance from the Chinese sighting, suggesting the wreckage could be as much as 300 miles clear of the volcanic ridge.
“We think the crash site is not in the region with these volcanoes,” Professor Chari Pattiaratchi of the University of Western Australia said, adding that the sea bed in the areas where other satellites had spotted objects was “flat."
Adding to the confusion is the lack of detailed charts of the sea bed. Australia’s defense ministry told the Sydney Morning Herald newspaper that the depth of the ocean floor meant it posed little risk to shipping and had not been mapped in any detail by the Australian Hydrographic Service.
"There is no detailed understanding of what the sea floor terrain looks like"
Researchers last conducted sea floor survey in the area almost 20 years ago and used outdated technology, Beaman told the newspaper. Some surveys charted strips about 40 miles wide while other research ships had gathered detail on the sea floor as they sailed from one port to another along a path between six and 12 miles wide.
''You're left with gaps of hundreds of kilometers where there is no detailed understanding of what the sea floor terrain looks like,” Beaman said.
Adding further difficulty is the inhospitable environment around the search zone, which is in an area known as "the Roaring Forties", notorious among mariners for its rough seas.
"In general, this is the windiest and waviest part of the ocean," University of New South Wales oceanographer Erik van Sebille told AFP. "In winter, if a storm passes by you can expect waves of 10-15 meters (32 to 50 feet)."
Alastair Jamieson reported from London.