Modem cities depend heavily on utility systems for their day-to-day operation and earthquake threats to utility systems become increasingly important in proportion with the level of urbanization. Due to the great potential for destruction, damage and disruption, the seismic problems of utility systems have recently attracted researchers. It became apparent that the seismic behaviour of buried pipeline systems is quite different than that of above-ground structures. In this paper, an updated and detailed review of the earthquake response and seismic-resistant design of underground piping systems is presented.Similarly, the 1923 Kanto earthquake in Tokyo resulted in the destruction of 40 per cent of the city by fire and 25 railroad tunnels were also damaged. In Yokohama, the rupture of water mains caused flooding in addition to fire. The 1952 Kern County earthquake caused severe damage in four railroad tunnels.'06 Underground pipeline systems have also been extensively damaged in severe earthquakes, such at Kanto 1923, Long Beach 1933, Fukui 1948, Alaska 1964, San Fernando 1971, Managua 1972 and others.Due to the great potential for destruction, damage and disruption, the seismic problems of utility systems have recently attracted the attention of researchers.' It became quite apparent that the seismic behaviour of buried pipeline systems is quite different than that of above ground structures. For example, bridges and dams, for which horizontal inertial force is the most important factor, are mostly designed by the seismic coefficient
