Using AUV Technology to Map Underwater Volcanic Activity

Scientists at Monterey Bay Research Institute have spent the last year using AUV technology to map the ocean floor. There work has taken them into a number of environments on the west coast including the northern coast of California where they have been studying three-kilometer wide scour marks on the seafloor. They have been documenting lava flow from a volcanic eruption off the coast of Oregon, and are developing new theories regarding one of the largest offshore faults in central California. The AUV has been flying 165 feet above the ocean floor using sonar to map the bathymetry, bathymetry so detailed it is programmed to chart features as small as 5 inches in height. The AUV used by MBARI, the D. Allan B. is gathering data using three different sonar systems, collecting information on depth, sub-bottom features and bottom texture. During the summer MBARI teamed up with Oregon State University and began to collect data on a volcanic eruption off the Oregon coast.

The university was using ROV technology to study the Axial Seamount located 170 miles offshore. During their studies the team from the university noticed a number of instruments that had been placed on the seafloor were missing. During this time MBARI had also been conducting studies in the same area and noticed the bathymetry had changed. By collaborating with Oregon State and comparing data, both teams realized the recent volcanic eruption had covered a large area with up to nearly 10 feet of fresh lava. By comparing the mapping done prior to the eruption, and following the eruption, scientists are able to understand the amount of lava released during the recent volcanic activity. They also discovered that the new eruption reoccupied many of the same fissures and followed a flow pattern that basically mimicked the existing flows—information that would have been impossible to gather through ROV dives or sonar surveys using surface ships.