Earthquakes in the northern hemisphere during the years 1964--1970 were examined for a sidereal period. High chi square values were found but were lowered by canceling the 'midnight peak' in the newwork detection capability. The 1964 Alaskan earthquake and the 1965 Aleutian earthquake produced large numbers of aftershocks, which are believed to be the main cause of the bias which produced the high chi square values.