Vibration of water surface excited by a vibrating object buried in sediment: simulation and measurements*

The laser-acoustic detection of buried objects, such as landmines, uses elastic waves in the ground and a laser vibration sensor to create a vibration image of the ground surface. This method provides high probability of detection and low false alarm rate. Detection of landmines buried in underwater sediments is of great importance for humanitarian and military demining. However, extension of the laser-acoustic technique to underwater buried objects present a serious challenge due to the effects of the water layer. The presented work investigates the possibility of detection of an object buried underwater by sensing the vibration of the water surface. The vibration pattern of the water surface caused by an underwater buried vibrating object is simulated using COMSOL software. The simulation results are compared with laboratory measurements of the water surface vibration by using a scanning laser Doppler vibrometer. The results show how the vibration pattern of the water surface varies with the height of the water layer.