Mapping hydrothermal discharge with multibeam echosounders: Insights from numerical simulations and laboratory experiments

Seafloor hydrothermal vents, primarily found atop mid-ocean ridges and hotspot submarine volcanoes, act as key conduits for transferring heat and chemicals from the Earth’s interior to the ocean. Active acoustic techniques, such as multibeam echosounder, are increasingly employed to detect buoyant plumes from these vents through backscatter imaging of the water column over the abrupt seafloor topography typical of hydrothermal vent fields. Here, we present an alternative method for mapping seafloor hydrothermal discharge based on the loss of coherence (decorrelation) in seafloor backscatter between transmissions separated by short time intervals. Originally implemented on a stationary platform, this method has been adapted for use on underwater vehicles during seafloor surveys. We evaluate the effectiveness of the method using synthetic data from model simulations and sonar data from a tank experiment. In this presentation, we share the results from these numerical and laboratory experiments and discuss insights for implementing the method in future field operations.