2010 – USNS "Sumner" – On 7 October 2010, further sonar mapping of the Challenger Deep area was conducted by the US Center for Coastal & Ocean Mapping/Joint Hydrographic Center (CCOM/JHC) aboard the 4.762-ton "Sumner". The results were reported in December 2011 at the annual American Geophysical Union fall meeting. Using a Kongsberg Maritime EM 122 multi-beam echosounder system coupled to positioning equipment that can determine latitude and longitude up to accuracy, from thousands of individual soundings around the deepest part the CCOM/JHC team preliminary determined that the Challenger Deep has a maximum depth of at , with an estimated vertical uncertainty of ± at two standard deviations (i.e. ≈ 95.4%) confidence level. A secondary deep with a depth of was located at approximately to the east at in the eastern basin of the Challenger Deep.