An interferometric seismic sensor: theoretical model and experimental performances

Laser Optical Interferometry has been introduced in different fields of research for applications requiring very high precision displacement measurements. We have applied optical interferometry for the solving the problem of amplitude and direction measurement of seismic waves. In particular we propose a Michelson Interferometer as a velocimeter with optical readout. In this work we demostrate that a simple array of two Michelson interferometer can be used as an effective seismic sensor to measure the velocity of ground motion. The sensitivity of such device should be delimited only by the enviromental parameter that can be monitored and controlled. A preliminary experimental test on this technique confirms the theoretical results: in fact there is a good agreement with a standard accelerometer for seismic application.