Evaluation of volcano flank instability triggered by dyke intrusion

Instability of volcano flanks may result from the mechanically and thermally generated pore fluid presure that accompany dyke intrusion. These complementary methods of pore presure generation act on potential basal failure planes, decreasing effective stresses and consequently decreasing frictional resistance to failure. The twin agents of pore pressure generation provide a rational and quantifiable means of initiating and sustaining flank instability, even as the driving forces provided by magma pressurization ultimately drop as flank displacement is initiated. Pore pressures developed by mechanical and thermal effects are readily evaluated using simple, but mechanistically rigorous, models.