Waves in the diapir tail as a mechanism of hotspot pulsations

The one-dimensional (1D) problem of magma rising through a volcanic channel is identical in its statement to the problem of chemical-density or thermo-chemical convection in an unbounded medium. The present work demonstrates how the rise of a low-viscous, buoyant material through an ambient environment with significantly higher viscosity can be successively described as a 1D problem of viscous fluid dynamics. The suggested analytical model is applied to describe the upwelling of a less dense material in the tail of a diapir through the mantle to the Earth??s surface. The linear study of wave disturbances in the shape of the conduit shows that the buoyant material tends to uprise by portions, which probably accounts for the pulsed activity of the hotspots appearing on the surface above the diapir.