 Larger pumice blocks rise for a more extended period of time (minutes to hours) in comparison to smaller pumice fragments because of gases trapped within vesicles and the very fine ash fragments may become entrained into the rising plume of gas and heated water because of the low density and weight.Therefore, subaqueous silicic pyroclastic eruptions may be diminished in the course size fraction as well as the very fine ash size fraction based on the buoyancy of the material in the water medium.These characteristics may be important in determining the style of subaqueous eruption and emplacement mechanism.