Since 1972, earthquake ground accelerations has been observed at a site of apartment house buildings in Kawaguchi, Saitama Prefecture,constructed by Japan Housing and Urban Development Corporation. The observation site is located distant approximately 15 kilometers north from center of Tokyo. Seven seismographs were installed at the levels of-1, -7, -14, -21, -30, -43 and -60 meters from the ground surface at this site. Only east-west horizontal component of ground motions can be observed for all the seismographs.

In this paper, digitized data of eighteen earthquake records observed at this site during June, 1978 to October, 1980 are presented.Frequency characteristics and distribution of maximum accelerations of these eighteen sets of records are also presented herein. The biggest earthquake in Magnitude observed during this period was the Of f Miyagi Earthquake of 1978, which caused severe damages of buildings in and around Sendai area, northern part of Japan. The maximum accelerations recorded in this period was 62.1gals at the ground surface.

^*Working Group Members
Y. kitagawa, Head of Dynamics Division, S. E. D.
Y. Sugimura, Head of Geotechnical Engineering Division,

S.E.D.
Y. Yamazaki, Head of Large-Scale Structure Testing Division,
P. D.
H. Mizuno, Senior Research Staff of I. I. S. E. E.
I. Ohkawa, Research Staff of I. I. S. E. E.
S. Arakawa, Staff of Housing and Urban Development Corporation

(Person in charge of this volume Y. Yamazaki)

S. E. D. Structural Engineering Department
P. D. Production Department
I. I. S. E. E. International Institute of Seismology and Earthquake Engineering