Numerical modeling of lava flow cooling applied to the 1997 Okmok eruption: comparison with AVHRR thermal imagery

Abstract

Throughout February and March of 1997, Okmok volcano, in the eastern Aleutian Islands of Alaska, erupted a 6 km long lava flow of basaltic a'a within its caldera. A numerical model for lava flow cooling was developed, building upon existing lava cooling models, and applied to the flow to better understand the nature of its cooling. The model predictions were then compared to Advanced Very High Resolution Radiometer (AVHRR) data collected over the flow. Daily data of rainfall and ambient temperature, as opposed to yearly averages used in comparable models, greatly increased the accuracy of the model. Furthermore, convective cooling of the lava surface was observed to be the dominant heat loss process during extended cooling indicating the convective heat transfer coefficient is a prime determinant of the accuracy of the model. The model's flexibility allows application to flows beside that of the 1997 Okmok eruption.