Intraplate volcanism: Although most volcanic rocks are generated at plate boundaries, there are a few exceptionally active sites of volcanism within the plate interiors. These intraplate regions of voluminous volcanism are called hotspots. Twenty-four selected hotspots are shown on the adjacent map. Most hotspots are thought to be underlain by a large plume of anomalously hot mantle. These mantle plumes appear to be generated in the lower mantle and rise slowly through the mantle by convection. Experimental data suggests that they rise as a plastically deforming mass that has a bulbous plume head fed by a long, narrow plume tail. As the head impinges on the base of the lithosphere, it spreads outward into a mushroom shape. Such plume heads are thought to have diameters between ~500 to ~1000 km.
Ring of fire: The Ring of Fire is an area where a large number of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. In a 40,000 km (25,000 mi) horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements
Lava: Hot molten or semifluid rock erupted from a volcano fissure, or solid resulting from cooling of this.
Magma: Hot fluid material below or within the earth's crust from which lava and other igneous is formed by cooling
Viscosity: The state of being thick,sticky and semi-fluid in consistency due to internal friction
silica content: used usually in form od its prepared white powder chiefly in the manufacture of glass, water, glass.