Dike intrusion as a trigger for large earthquakes and the failure of volcano flanks

Pore fluid pressures induced through dike intrusion have the capability to trigger large earthquakes and to initiate and sustain massive and catastrophic failure of volcano flanks. Suprahydrostatic pore pressures are generated as a result of both mechanical and thermal straining of the rock-fluid medium. Mechanical strains and resulting pore pressures are described using an analogy to a moving volumetric dilation within a porous elastic medium. Thermal pore fluid pressures are simply represented by a static diffusive model subjected to uniform temperature rise at the dike interface. Resulting excess pore pressure distributions acting along the base of a wedge-shaped slide block are used to define the stability of the flanks when subjected to the magma pressures that accompany intrusion. These phenomenological models of pore pressure rise and stability control may aid comprehension of the cyclic growth, lateral expansion, and subsequent destruction of shield and stratovolcano flanks. -from Authors