Passive Acoustic Localization of A Natural CO2 Seep - Implications for Carbon Capture and Storage

Localizing greenhouse gas (e.g., CO
2
) leakage from the sub-seabed is necessary to determine the passive acoustics as an effective environmental monitoring tool above marine carbon storage sites. In this paper, we develop an approach to verify the passive acoustic technique using hydrophones at different positions to localize a discrete natural CO
2
vent site offshore the island of Panarea, Sicily. A cross-correlation method determines the relative arrival time of bubble sounds at these hydrophones from the same gas seep. By comparing the time difference of sound arrivals and computing the direct travel path, we are able to localize the vent site. The results show that our approach is able to localize a CO
2
gas seep with a gas flux of 2.3 L/min at horizontal distances of up to 6.67 m with small errors.