It has been three years now since flight MH370 went missing. This effort to localize the flight with hydrophones has continued in earnest since the recording data was first acquired about nine months ago. After dozens of false starts and continuing refinements of the analysis algorithms, a new candidate location has been revealed that is consistent with both 7th Arc timing and new drift origin estimates.
Signal intensity at the Cape Leeuwin H01 triad hydrophone array is plotted on a cartographic map overlay according to travel distance and bearing for a 00:19:37 UTC impact. To minimize noise, multiple maps using correlation window sizes from 2 to 30 seconds are averaged into a final result.
Each hydrophone pair is assigned an RGB color channel, so summation to white or grey would show the best agreement. Saturated colors are more likely to be artifacts of strong distant events at a different bearing, or noise from waves breaking above the hydrophones. Green spreading around the radius of H01 in this image is due to the near end-fire arrangement of hydrophones 1 and 3.
Clearly evident in the map is a detection on the 7th Arc at S28.75 E99.25 (H01 bearing 292.0 degrees). Close by to the SW is a signal at H01 bearing 289.4 degrees, with the signal spreading at an offset angle.
One explanation for the weaker signal west of the 7th arc is that it is a reflection off of the eastern slope of the Gulden Draak Seamount below it. This could account for the unique spreading of the signal away from the H01 radius. The apparent displacement to the west would then be due to the time delay over the reflection path.
An extrapolation of this theory that incorporates the slightly shifted implosion candidate is that the stronger detection on the 7th Arc is also a reflection off of the seamount.
There has been ongoing speculation whether a surface impact over deep water would be conducted into the SOFAR channel (about 1000 m in this area), where signals propagate with little loss. There is evidence that signals to the NW of Cape Leeuwin are attenuated on H01 when transiting a plateau that reaches up to a depth of 1500 m, even though the hydrophones are suspended in the SOFAR channel.
Seismic survey soundings near the surface over deep water do appear to propagate well when the depth over the path to the hydrophones is at least 2500 m, as evidenced by bearing 35 noise sources reaching H08.
The Gulden Draak Seamount rises to within 1100 m of the surface, very close to the path toward Diego Garcia array H08. This may effectively be blocking a signal from the SE side of the sea mount.
Signals can also be reflected by terrain, and it may be that the signal is detectable at H01 by a surface event being reflected off of the seamount slope into the SOFAR channel. If so, the actual impact site may be just east of the reflected signal peak. A tentative late implosion candidate on H01 bearing 293.1 is unfortunately co-mingled with a stronger ice event, but hints at a source for a reflection slightly east of the sea mount.
A suggested search approach would center at the signal peak location on the 7th Arc with an oblong east-west spiral path. Detailed bathymetry of the terrain should improve the estimates of reflection paths.