Monday, August 27, 2018

Summary of the 2018 expedition

Science team for 2018 expedition.
It’s always a great feeling at the end of a research cruise when the ship is coming back into port and I know we have accomplished all your main science goals. In oceanography, there are many things that can go wrong at sea, from bad weather to equipment malfunctions that can prevent you from working, that success is never guaranteed. So I always have a sense of relief when we are able to get the work done that we set out to do. Thankfully, that is the case this time. The other feeling I have is gratitude for everyone on board the ship who contributed to our success – from the ship’s crew, the operators of the vehicles we use, and the science party.

ROV Jason launch.
Our main goal on this expedition was to continue our measurements of the volcanic inflation going on at Axial Seamount since its last eruption in April 2015. We accomplished that in several different ways during this cruise: 1) We repeated pressure measurements on an array of seafloor benchmarks inside the summit caldera with the Jason ROV. 2) We recovered and re-deployed bottom pressure recorder instruments that had been continuously recording on the seafloor at various locations for the past year. 3) Thirdly, the MBARI AUV made dives to collect high-resolution bathymetry that we will compare with previous surveys to measure depth changes over a much larger area than where the pressure measurements are made.

Control van monitors for ROV Jason

Mooring recovery.
Together all these data will give us a good view of how much the surface of the volcano (the seafloor) is moving up (or down), and how that movement varies from place to place. That information provides insights about the reservoir that stores magma inside the volcano between eruptions, such as its size, shape and depth, and the rate at which magma is being supplied and how that supply changes with time. It will also help us anticipate when Axial will be ready to erupt again. So far, it looks like it will still be a few more years, but Axial might be getting close when our next expedition is scheduled in the summer of 2020. In the meantime, you can see real-time monitoring data from Axial Seamount at this link.

MBARI mapping AUV deployment.

-Bill Chadwick