The physical structure of convoluted surfaces and fluid interfaces in turbu
lence is quantified by a distribution of geometric scales. A scale measure
suitable for multidimensional surfaces and a one-to-one correspondence betw
een the scale distribution and the coverage dimension are used to analyze t
he scale dependence of the interfacial geometry. Application to concentrati
on interfaces in a turbulent mixing flow indicates that the statistical law
s exhibited at the small scales can be quantified and modeled. Based on the
scale distribution, dimensionless measures of folding and wrinkling of the
fluid interfaces are introduced which are useful to quantify the contribut
ions of the large-scale and small-scale turbulent flow structure to the int
erfacial geometry.