Meniscus dynamics causing strain energy dissipation in three-phase systems, e.g., partially saturated rocks, is being studied as a method of detecting changes in the chemical composition of these systems. New observations of dynamic menisci and thin films on contaminated and clean surfaces have been made. Thin films on contaminated surfaces were observed to exhibit time-dependent relaxation. We propose that this relaxation is responsible for a poorly understood attenuation peak previously observed in partially saturated, contaminated systems. ¿ 2001 American Geophysical Union