 Basaltic lava flows have a high ferromagnesian ( iron and magnesium ) content and erupt at temperatures between 1000 ° C and 1200 ° C ; these values are higher than those of other common igneous rocks . Due to the high temperature of this lava flow , the lava would be extremely fluid ( it has low viscosity ) , allowing the lava to travel long distances from the magma source ( the volcano or vent ) . These extremely fluid lavas have flow speeds that depend heavily on underlying terrain , with a maximum of almost 60 kilometres per hour ( 37 mph ) in underground lava channels . Flow independent of such channels and tubes moves quite a bit slower , averaging speeds of 1 @.@ 6 km ( 1 mi ) per hour . However , this flow speed changes considerably within the flow , with speeds depending heavily on depth and degree of cooling that the flow has experienced ( essentially distance from the vent ) . Although the Nazko area flows would not be highly basaltic like those found in Iceland or Hawaii , lower depths are unlikely as viscosity is normally higher . 
