Netlike plastic flow in the lower lithosphere, as viscoplastic flow involving plastic flow network, controls tectonic deformation and dynamic processes within the continental plate.

The equations describing the flow of a viscoplastic fluid on a rotating disk are derived and are solved by perturbation technique and numerical computation respectively for 2 cases.

And, taking terms of an upper bounded approach, the existence condition for a normal flow regulation is obtained for the voided viscoplastic material.