Thermal instabilities during flow of magma in volcanic conduits

The possibility that the thermal feedback process may be the cause of the explosive nature of volcanic extrusions is examined. To demonstrate the changes in flow during upward flow of magma in volcanic conduits, the velocity distributions and discharge rates along with the growth of instability are shown for the dike. Comparisons with the widths of dikes and discharge rates of volcanic cone in the earliest forming period of its activity indicate that thermal feedback may actually play an important role in the magmatic transport. Thermal feedback may provide an explanation for the observation that volcanism is essentially a recurrence of explosive and exhaustive discharge of magma.