Most of the previous studies on soil liquefaction were based on either laboratory tests or macroscopic in-situ obserivation of liquefaction related phenomena such as sand boils. In-situ measurements of pose water pressure and ground motions durngn earthquakes are urgently required for further developement of liquefaction studies. The present report offers results of the observation of in-situ excess pore water pressures and groun motions measured during the 1987 Chiba-Toho-Oki Earthquake of magnitude 6.7.