Axial seamount has a caldera at the summit that is 3 km wide and 8 km long, and up to 100 m deep. The floor of the caldera is about 1500 meters deep, or about three quarters of a mile below the ocean surface. The map at left shows high-resolution bathymetry in color that was collected by our colleagues Dave Clague and Dave Caress at the Monterey Bay Aquarium Research Institute (MBARI) with an autonomous under water vehicle (AUV). The colors help show what areas are shallow (reds) and which areas are deep (blues).
The black outlines superimposed on the map below show the lava flows that were erupted in 2011, and the yellow lines are the eruptive fissures where the lava came out of the ground, along the upper south rift zone of the volcano.
The icons overlain on the map below show where we’ll be spending a lot of time during our cruise. The red dots are hydrothermal vents, mostly near the caldera walls and along the upper south rift zone, and white dots are places where we’ll be making pressure measurements to see how much the volcano has re-inflated since the 2011 eruption.
That’s a quick introduction to the summit of Axial Seamount where we’ll be making dives during our expedition.
Here is a video describing Axial's caldera:
-Bill Chadwick, Oregon State University
