Of course, this is balanced with gas content -- if the magma contains more gas bubbles, it will erupt more violently, and if it contains less gas, it will erupt more calmly.
A memorandum of understanding (MOU) is an agreement between two parties in the form of a legal document. It is not fully binding in the way that a contract is, but it is stronger and more formal than a traditional gentleman's agreement. Sometimes, the term is used as a synonym for a letter of intent, particularly in private law.
An RTU is a type of AHU. AHU stands for Air Handling Unit and the acronym RTU means Rooftop Unit. The Roof Top Unit is an outdoor AHU. As RTUs are mounted on the roof, there is no concern about creating extra space indoors for it as would be the case for the other types of AHU.