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 50 cm (20 in) 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 10,994 m (36,070 ft) at 11°19′35″N 142°11′14″E﻿ / ﻿11.326344°N 142.187248°E﻿ / 11.326344; 142.187248, with an estimated vertical uncertainty of ±40 m (131 ft) at two standard deviations (i.e. ≈ 95.4%) confidence level.[35] A secondary deep with a depth of 10,951 m (35,928 ft) was located at approximately 23.75 nmi (44.0 km) to the east at 11°22′11″N 142°35′19″E﻿ / ﻿11.369639°N 142.588582°E﻿ / 11.369639; 142.588582 in the eastern basin of the Challenger Deep.[36][37][38][39]