An analytical approach for determining strain ellipsoids from measurements on planar surfaces

A new method is proposed to determine strain ellipsoids from measurements made on planar surfaces. It is similar in theory to that of Robin, P.-Y.F., [2002. Determination of fabric and strain ellipsoids from measured sectional ellipses - theory. Journal of Structural Geology 24, 531-544], but is more flexible and hence more applicable because it can incorporate different kinds of strain measurements, especially when only the pitches of the long/short axes of strain ellipses are measured on planar surfaces. It is not necessary to estimate both the relative and absolute strain ellipsoids at the same time, as Robin, P.-Y.F., [2002. Determination of fabric and strain ellipsoids from measured sectional ellipses - theory. Journal of Structural Geology 24, 531-544] and others did. The former may be estimated before the latter. The feasibility of the proposed method is demonstrated by three artificial examples and one real example.