28 April 2014: Triangle of CTBTO HA stations in Indian Ocean

The International Monitoring System (IMS) hydroacoustic network is designed to monitor nuclear explosions in the oceans and at low altitudes above the surface of the oceans. For example a few kilogram charge exploded in the sound fixing and ranging (SOFAR) channel off (say) South Africa would be clearly recorded on the hydroacoustic (HA) station at Cape Leeuwin, southwest Western Australia.

The verification regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) is designed to detect any nuclear explosion conducted on Earth – underground, underwater or in the atmosphere.

On 24 April 2014 an update suggested that acoustic measurements from the hydroacoustic station at Cape Leeuwin (south-western tip of Western Australia) which monitors the ocean under the CTBT may have been used to determine bearing or range to an acoustic event, possibly caused by a sea surface impact of MH370.

One intersection of the acoustic ring centred at Cape Leeuwin and Inmarsat 8:19 (00:19 UTC) ping ring can be defined by the current search area, setting the radius (range) of the acoustic ring. The other intersection is therefore derived and happens to be very close to the previous search area.

This update extends this analysis by including all three CTBT hydroacoustic stations in the Indian Ocean: Cape Leeuwin, Diego Garcia, and Crozet Islands. The list and profile of CTBT stations can be found here. It is unclear, though, whether the station on Crozet Islands was operational or still under construction on 8 March 2014.

The Google Earth snapshot below shows the approximate 8:19 (00:19 UTC) Inmarsat ping ring (a white arc); an acoustic ring centred at Cape Leeuwin; the current search area pointed to by a red line from Cape Leeuwin; and a triangle formed by the three CTBT hydroacoustic stations: Cape Leeuwin, Diego Garcia, and Crozet Islands

If all three stations were operational on 8 March 2014, then the chances of detecting an acoustic event within the triangle would have been higher than that of the outside. And so, if such a detection was not reported, it could mean that the segment of the 8:19 ping ring outside of the triangle, including the current search area, would be more likely to contain the location of an impact.

If, on the other hand, Crozet Islands HA station is still under construction, then there is still a symmetry with respect to the line between Diego Garcia and Cape Leeuwin...

Please drop an email if you have some information on the subject. Thanks.