EXAMINATION ON THE ARRAY OBSERVATION OF STRAINS INDUCED AT GROUND SURFACE DURING EARTHQUAKES

Abstract

The authors have been continuing the observation on 1 metre gauge measurement of strains induced at ground surface during earthquakes. In the present study, the array observations of ground surface strains have been conducted with the interval of each stations of about 17 metres and the maximum length of 100 metres. The pure shear strain condition was found to prevail at each station. It was also found that there was a specific direction of the principal strain. At one of the stations, the strain measurements were conducted at the vicinity of a ground water level. The strain amplitude at this location was larger than those at the other stations.