Orange triangles are location of continental database entries.
Blue dots are location of oceanic datapoints.
In 1988, work was started on a global database intended to characterize the Earth s crust. Today, this database has over 1700 entries, covering a large portion of the Earth s surface. The primary data source is from published literature detailing the results of seismic refraction profiles, although some unpublished results have been used as well, especially in Russia and China. The 1-D model includes the thickness and seismic velocity for each crustal layer as well as annotations of sedimentary layers, velocity gradients, and the moho depth. Other crustal parameters are added to each point to create a complete image of the Earth s crust.