5824 20220901124119.0 CTALK-2022-0071 Caudron, C Seismo-acoustic measurements in the Laacher See, Germany 2022 2022-09-05 To date, seismo-acoustic approaches have mostly been deployed in non-volcanic areas. We will present preliminary results gathered at the Laacher See volcanic lake in Germany where bubbles seep due to volcanic and biological activity. We deployed a 500-m underwater fibre-optic cable connected to a DAS interrogator over 48h. Supported by a series of videos, our preliminary results show that bubbles are detected at different locations along the cable. Frequencies associated with the degassing activity are recorded down to a few Hz up to the kHz. The waveforms show a clear signature, suggesting that detection algorithms could easily be implemented to track their occurrence over time. Finally, the multi-split beam echo-sounder SeapiX from iXblue and two hydrophones were deployed in standing mode scanning the same area. These data will allow us to estimate the size and rising velocity of bubbles. NO Laacher See Volcano CO2 Echosounder Hydrophone DAS Bubbles Wollin, C. Spica, Z. Schmidt, B. Yates, A. Haberland, C. Jouve, G. Mosca, F. Matte, G. Krawczyk, C. Jousset, P. Vandemeulebrouck, J. Mordret, A. Roux, P. Miao, Y. De Batist, M. Albers, S. VLIZ, team Lecocq, T. Van Camp, M. 101th JLG, INTRACONTINENTAL BASALTIC VOLCANIC FIELDS Development and testing of hypotheses michel.vancamp@observatoire.be Contributed CTALKCONT