Question

What is the axis of a fold?

(a) Line drawn normal to the hinge line

(b) Line drawn at 60° to hinge line

(c) Line drawn parallel to hinge line

(d) Line which doesn’t pass through hinge line.

The question was asked in semester exam.

This key question is from Parts of a Fold topic in section Folds and Folding of Engineering Geology

Answer 1

Right choice is (c) Line drawn parallel to hinge line

The explanation is: Axis of fold is defined as a line drawn parallel to the hinge line of a fold. In other words, line representing the intersection of the axial plane of a fold with any bed of the fold.