The Observations of the Earth Tidal Strains in Old Osakayama Tunnel

Abstract

Observatons of the earth tidal extensions have been performed with newly improved highly sensitive extensometers in the old Osakayama tunnel. The influences on the observed extensions caused by the atmospheric tide and the existence of the tunnel have been studied theoretically and experimentally. According to the study of our observations, these atmospheric and hole effects are large in the orthogonal direction to the tunnel. From these studies the revised values of the tidal factors of the vertical, the areal and the dilatational strains have been obtained.