Seismo Lab Brown Bag Seminar

Hydroacoustic monitoring serves as a powerful tool for detecting and characterizing submarine geohazards, offering unique insights into underwater mass-wasting events, seismicity, and volcanic unrest in regions where traditional geophysical networks provide limited coverage. In this talk, I will present two case studies that demonstrate the application of hydroacoustic techniques in identifying distinct underwater processes. The first case investigates the 14 March 2024 disruption of submarine communication cables offshore Ivory Coast. Hydrophone triads near Ascension Island recorded a low-frequency (<60 Hz) signal on 12 March. Using Generalized Cross-Correlation with Phase Transform analysis, we obtain a bearing consistent with the Trou Sans Fond Canyon, where steep bathymetric gradients suggest conditions favorable for slope failure. The absence of corresponding seismic signals on land-based stations supports a marine origin, marking the first documented detection of a submarine landslide from continental slope failure using hydroacoustic data. The second case examines hydroacoustic signatures of submarine seismic and magmatic processes along the western Aleutian Trench. A hydrophone network deployed ~100 km north of Adak Island between June 2022 and June 2023 captured different acoustic signals, including long-duration (<60 Hz) spindle-shaped T-phases associated with seismic-to-acoustic energy conversion at the seafloor, as well as short impulsive signals (40–100 Hz) that peaked in activity during March 2023. By integrating hydroacoustic detections with land-based seismic catalog, we identify a spatial and temporal correlation between the impulsive signals and seismic unrest beneath Tanaga Island. This unrest is likely to be associated with shallow magma transport.