3953 20190128153602.0 POSTER-2019-0042 Burlet, Christian Passive geophysics inside underground cavities: examples of HVSR surveys in the caves of Han-sur-Lesse, Belgium and Bruniquel, France 2018 2018-04-10 NO Van Noten, Koen Delaby, Serge Lecocq, Thomas Verheyden, Sophie Genty, Dominique Jaubert, Jacques European Geosciences Union General Assembly, Vienna, Austria koen.vannoten@observatoire.be CPOSTER