So, How Deep Is the Mariana Trench?

HMS Challenger made the first sounding of Challenger Deep in 1875 of 8184m. Many have since claimed depths deeper than Challenger's 8184m, but few have provided details of how the determination was made. In 2010, the Mariana Trench was mapped with a Kongsberg Maritime EM122 multibeam echosounder and recorded the deepest sounding of 10,984 +/- 25m (95%) at 11.329903 degrees N/142.199305 degrees E. The depth was determined with an update of the HGM uncertainty model combined with the Lomb-Scargle periodogram technique and a modal estimate of depth. Position uncertainty was determined from multiple DGPS receivers and a POS/MV motion sensor.