Liquefaction and cold volcanism

The escape of pore fluid from a granular matrix has the tendency to localize into relatively thin tubes. This manifests itself in sand/water volcanos at the ground surface. In this paper this phenomenon is attributed to the following two mechanisms: (1) opening of horizontal gaps filled with pore fluid, and subsequently, (2) a sort of Rayleigh–Taylor instability exhibited due to the fact that a heavy fluid rests upon a lighter one. If the pore fluid is water, then we have the so-called cold volcanism. If the pore fluid is molten rock, then we have conventional volcanos.