THE MARIANA TRENCH 1
Therehave been numerous attempts to establish the deepest point of theocean over the centuries. Ferdinand Magellan was one of the firstpeople to attempt this in 1521 using the sounding technology. Effortsby HMS Challenger in 1875 declared that the Challenger Deep was thedeepest depth in the Mariana Trench at 8184 m, which increased to10,994 ± 40 m after the exploration by a U.S. Extended ContinentalSelf cruise. In 1952, the HMS Challenger II established a depth of10,900 m at 11019’N/142015’Ealthough it was reduced to 10,863 m after a correction of themeasurement systems (3). More recent mapping by Kongsberg MaritimeEM122 established a depth of 10,984 ± 25 m in 2010 at11.3299030N/142.1993050E,which was more refined than that reported by HMS Challenger II.Mappings done by Japan, University of New Hampshire, and theUniversity of Hawaii do not differ much in the deepest depth andlocation.
The determination of the deepest depth is faced bya number of challenges that include the uncertainties in themeasurement of echosounders, variability of sound-speed due torefraction, and the development of data processing methods. As aresult, some models such as the Hare-Godin-Mayer integrate theuncertainties to provide results with higher confidence levels.According to the authors, data processing approaches present thebiggest uncertainty in the determination of the deepest depthuncertainty can be reduced through the avoidance of soundings thatcast doubt, use of estimations when data is not available or enough,and reducing the uncertainties in measurement (7). Differenttechniques such as the conversion of raw data in CARIS HIPS,processing in the ASCII format, and analysis using MATLAB wereutilized in the development of the 2010 estimates.
Gardner, J., Armstrong, A., Calder, B., & Beaudoin, J. (2014).So, How Deep Is the Mariana Trench? Marine Geodesy, 37(1),1-13. http://dx.doi.org/10.1080/01490419.2013.837849