The stress caused in buried pipe by earthquake ground motion is mainly influenced by relative ground displacement along the pipeline rather than ground acceleration. Very few field observations which can provide information on relative ground displacement are carried out. The earthquake observation with a seismometer array has been carried out by the Port and Harbour Research Institute. The six accelerometers (earth has two horizontal components) have been installed at every 500 m on straight line in the Tokyo International Airport. Eight records from this observation were selected for the analysis. A pipeline was supposed to be buried along the straight line and its deformation was assumed to be entirely same as that of the ground. The deformation of the ground was calculated by integrating the recorded ground acceleration. The pipe stresses were calculated according with the design code which is Ordinance of Technical Code for Petroleum Pipeline and with
the BART-Kinuura method. The stresses by both methods were compared with the pipe stresses based on the observation.
　Main conclusion is as follows: The pipe stresses calculated by Ordinance of Technical Code for Petroleum Pipeline were about four times as large as the value based on the observation at the place where the ground condition was almost uniform.