io's largest plumes, pele-type plumes, are created when sulfur and sulfur dioxide gas exsolve from erupting magma at volcanic vents or lava lakes, carrying silicate pyroclastic material with them. the few pele-type plumes that have been observed are usually associated with explosion-dominated eruptions, and are short-lived. the exception to this is pele, which is associated with a long-lived active lava lake eruption, though the plume is thought to be intermittent. the higher vent temperatures and pressures associated with these plumes generate eruption speeds of up to , allowing them to reach heights of between . pele-type plumes form red (from short-chain sulfur) and black (from silicate pyroclastics) surface deposits, including large -wide red rings, as seen at pele. the erupted sulfurous components of pele-type plumes are thought to be the result of an excess amount of sulfur in io's crust and a decrease in sulfur solubility at greater depths in io's lithosphere. they are generally fainter than prometheus-type plumes as a result of the low dust content, causing some to be called stealth plumes. these plumes are sometimes only seen in images acquired while io is in the shadow of jupiter or those taken in ultraviolet. the little dust that is visible in sunlit images is generated when sulfur and sulfur dioxide condense as the gases reach the top of their ballistic trajectories. that is why these plumes lack the dense central column seen in prometheus-type plumes, in which dust is generated at the plume source. examples of pele-type plumes have been observed at pele, tvashtar, and grian.