How Thick is the Earth's Crust?

In order to understand continental evolution and other geological processes, it is first necessary to develop a thorough knowledge of the Earth's crustal structure. We present a recently-updated contour map of the thickness of the Earth's crust using a 10-km contour interval, with the 45-km contour also included. This contour map was created from about 8000 individual crustal data points that have been acquired during the past 65 years. The contour map honors all available seismic refraction measurements for features with a dimension greater than 2 degrees. Crustal thicknesses in Eurasia, North America, and Australia are well constrained by seismic refraction data, while new data has enhanced resolution in Antarctica, South America, Africa, and Greenland. To a first approximation, the continents and their margins are outlined by the 30-km contour. The part of the continental interior enclosed by the 40-km contour and regions with crustal thickness of 45 to 50 km are found on all well-surveyed continents. Continental crust with thickness in excess of 50 km is exceedingly rare and accounts for less than 10% of surveyed continental crust. These observations, now available on a global basis, provide important information to be used for numerous scientific studies, including ongoing refinements to global crustal models.