Fault related folding structures have been investigated by many authors for geological studies of overthrust areas. Three basic models such as fault-bend folding, fault-propagation folding, and detachment folding were developed with distinct geological scenarios for fold thrust interactions. Each model has distinct geometrical relationship between fault and fold shapes.
In this paper we derive the geometrical shape of fault-bend folding with a simple shear deformation in a hanging wall. We show that the fault-bend folding can exist when a cutoff angle of the ramp fault is greater than 30 with a simple shear in a hanging wall. Also, we show the schematic diagram to easily evaluate the simple shear deformation in the thrust sheet from the geometrical shape of a fault-bend folding that is obtained by the reflection seismic method.

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