Why is it that our volcanoes do not produce ‘rivers of lava’ like the volcanoes in Hawaii?
The type of lava flow depends on the chemical composition of the lava. Lava with low silica content are less viscous (i.e., more “fluid”) and can flow freely downslope as in Hawai’i. Lava with higher silica content are more viscous (i.e., “stiffer”) and cannot flow as freely. They will tend to accumulate close to the vent (e.g., crater) and form lava dome. Our volcanoes in the region tend to produce viscous lava flows (e.g., dome at Soufriere Hills Volcano in Montserrat). But some have produced lava which are fluid enough to produce long distance traveling lava flows, as in St Vincent.