The objective of this proposal is to develop a technique capable of identifying, locating and quantifying leakages through liners or barriers that contain hazardous leachates. The technique is based on the use of seismic boundary waves. These waves propagate along soil/water and soil/soil boundary created by a liner or barrier. These boundary waves are focused on the liner interface and are highly sensitive to the conditions of this interface. Changes in moisture, void ratio and permeability can be detected and correlated to leakage events. On Phase I the feasibility of this concept was demonstrated by conducting a small scale field test. The objective of Phase II is to: confirm the concept, integrate the hardware, develop the analysis and interpretive software, develop implementation methods and interpretive techniques.