Science Report - 6/30/00
We arrived at the southern Cleft segment this morning and deployed an elevator mooring with 6 extensometer instruments on board (photo right). The elevator mooring allows us to get things up and down from the bottom that are too big, heavy, or awkward for ROPOS to handle by itself. The Juan de Fuca Ridge is the boundary between two tectonic plates that are slowly moving apart at an average of about 6 cm/yr. The extensometer instruments will be making very precise, daily measurements of the distance across the plate boundary, and so we can learn more about the character of spreading events. These extensometers are new versions of the prototype instruments we have used at Axial over the last few years - they can stay down longer, are more precise, and are better designed for making long-term measurements at the same site. ROPOS is just about ready to dive and will move the 6 instruments from the elevator and position them on the bottom across the spreading axis.

Elevator mooring used to transport instruments to ROPOS on the seafloor.