Visualization of Hydrothermal Plume Discharge Locations and Temporal Dynamics at ASHES Vent Field

The application of scientific visualization techniques focused on identifying locations where backscatter exceeds a threshold revealed unexpected locations of potential or actual venting (as well as the anticipated plumes). The plume dataset using the Cabled Observatory Vent Imaging System (COVIS) attached to the Ocean Observatories Initiative’s Regional Cabled Array in the ASHES vent field in the caldera of Axial Seamount on the Juan de Fuca Ridge. The dataset contains backscatter intensity measurements from July 2020 to September 2023. For each month, plume-imaging data — which record plume shape — were acquired on five different days (weekly). On each of those days, twelve measurements were taken at two-hour intervals, generating twelve grid files. The dataset was processed using MATLAB. First, morphological operations were used to extract the six largest clusters, and the center of mass of each was calculated from the mean of their x, y, and z coordinates. A nearest-neighbor tracking algorithm then matched each cluster with its counterpart in previous time steps. Results showed persistent cluster formation at certain locations. To validate this finding, the matched clusters over time were plotted on the bathymetry map where the original data were collected. In addition to constant cluster formation at the Inferno and Mushroom vents, significant clusters appeared at locations that are not expected to host large plumes. Unexpectedly, we identify recurring clusters 16 meters north and 18 meters west of known Inferno vent orifices (see yellow and green clusters in figure). Future work is required to investigate possible causes of the clusters at these unexpected sites. Nevertheless, this study provides valuable information for the analysis of acoustic data intended to capture the incidence of hydrothermal plumes at the ASHES vent field.