This study illustrates presents a set of the Long – Term Geoelectric Potential (LTGP) measurements that are collected for experimental investigation in Western Greece during a five–year period (1993 – 1997). During this period, many major destructive earthquake events occurred that caused human casualties and extended material damages. The collection and processing of geoelectric measurements was done by an automated data acquisition system at the Seismological Laboratory of the University of Patras, Greece. This novel study considers seismic activity of this area as a typical linear dynamic system and the dynamic relationship between the magnitude of earthquakes and Long – Term Geoelectric Potential signals is inferred by the Recursive Least Square algorithm. The results are encouraging and show that linear dynamic systems, which are widely used in modern control theory, can describe efficiently the dynamic behavior of seismic activity and become a useful interpretative tool of seismic phenomenon.