What role does Magnus Magnusson play during the 1973 volcanic eruptions in Heimaey?

In 1973, Magnus Magnusson is the mayor of Heimaey's town when the volcanic eruptions begin. His role is to assign priority to the lava cooling efforts. He tells Thorbjorn Sigurgeirsson to protect the harbor first and foremost. Without the harbor, the town cannot exist. If the harbor stays operational, the town can rebuild.