TODAY   |  April 08, 2014

Expert on jet search: Finding pings was ‘shocking’

Dr. Ellen Prager, a marine scientist and oceanographer, joins TODAY discusses the latest on the search for the Flight 370 black boxes, and explains the functions of an unmanned submarine mapping the ocean floor.

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This content comes from Closed Captioning that was broadcast along with this program.

>> go to dr. ellen prager. we need an education this morning, for sure. so we didn't hear anything today from what might have been the black boxes . what does that tell you? i mean, is that a fairly discouraging sign?

>> well, there could be a number of reasons why that is. one, relocating that spot is not easy. so find the spot again is one thing. you're working in a hugely hostile environment, very deep. there's also the question of the batteries. so it's discouraging, but it's not. honestly, finding those pings so quickly was shocking, for somebody like me that understands how vast the ocean is, how deep, and how difficult it is, i was really surprised.

>> perhaps a stroke of luck. when you think about them hearing that pinging sound for about two hours, and then on the backtrack for about 15 minutes , that's a good sign. are there other things in the ocean that could make a sound that would be like that, though?

>> there are things that can make chirps or clips, but not a regular beat like that. i think that's the key. is that when you hear that regular frequency, that ping, the chirp over and over , that's what they were looking for. and over that length of time. so let's say you heard a dolphin. you wouldn't hear it making a regular sound over two hours.

>> so let's say they are able to triangulate and relocate that sound, hear it again. that's when they would send this auv , which is an autonomous unmanned vehicle, i have now learned, down to basically map the ocean floor . but when it's that deep, how difficult is that and what's the terrain like there?

>> the terrain -- it's a little bit rough. south, there's a deep trench, which is a little bit scary. so what they'll do with the auv is they basically program it on the ship where to go. and they'll fly it under water, and then they'll be mapping swaths using side scan sonar . what happens is the echo from the sound -- if something's sticking up, will give you a strong signal. so it will be light colored. if something is behind that, it would be a weak signal, it would be dark. and use those echoes to create a map. but it's a very slow process. so they have to fly the auv , bring it back to the ship, download the data and process it all. so, you know, we're talking weeks to months, especially without the ping.

>> yeah, yeah. dr. ellen prager, it's a long road ahead. thank you very much.