Originally Posted by ushumgal
Reverting briefly to the acoustic detection a year ago, I wonder what effect that tall ridge (running northwest) to the north of the new search area would have on a pinger lying on the ocean floor. If the submarine was to the south of it and the pinger north of the ridge, would the ridge tend to block the sound from it, or would the ridge in fact help deflect the sound upwards to where the submarine was? Just an idle thought I had, knowing nothing of underwater acoustics.
That's an interesting question. Sound will hug a surface very nicely. So it might have traveled up-slope as a traveling wave and been launched back off the surface at the ridgeline. The efficiency of this mechanism would depend on wavelength, size of obstacles on the slope, mud on the slope, and a host of other factors. It is, however, a possible way for the location to be very muddied. Hitting a surface with different salinity or temperature might also lead to ducting or reflections that allow the signal to travel great distances. (Although I doubt the signal strength would support very much greater range than simply up to the submarine given auv-ee's good analysis.)