On the basis of fossil liquefaction structures observed in the Hokkaido University campus, paleoearthquakes that had struck Sapporo-city are discussed. The results are as follows: (1)Paleoearthquakes had occurred three times during last ca. two thousand and several hundred years. The latest paleoearthquake should be identified with the 1834 Ishikari-earthquake. The older paleoearthquakes occurred at around 2000 years BP. and during the time between A. D.10. century and the end of A. D.18. century, respectively. (2) The return period of earthquake is estimated to be from 2000 to several hundred years. (3) Active fault which caused liquefaction can not be decided, because of lack of the historical records.
