These fumaroles exhale a mixture of hydrogen sulfide and sulfur dioxide, which is produced at a rate of . In addition they contain hydrogen, hydrogen chloride, hydrogen fluoride and nitrogen, while carbon monoxide, methane and oxygen are only minor components. Temperatures of have been measured, and the source appears to have temperatures of up to . The composition of the fumaroles indicates that the gases are ultimately of mainly magmatic origin, but interact with a slightly colder hydrothermal system before reaching the surface.