THE KURRAJONG EARTHQUAKE. 85 



fatal, for the buildings would have been very much shattered and 

 many thrown down. At this time the weather was hot and close, 

 and the clouds very large. Thunder and lightening is very com- 

 mon, but of late we have not had any. I lament that I was 

 asleep, as at first when it waked me I was like as if I was stupified. 



Yours etc., George Oaley." 



From this letter it appears that the shock was greater 

 in the Hawkesbury district than at Sydney, so that quite 

 probably the earthquake originated along the Kurrajong 

 Fault. 



Doubtless other earthquakes have from time to time 

 been felt at Sydney, and it is desirable that accounts of 

 these should be collected and recorded; but this work is 

 beyond the scope of the present paper. 



The first reports of the recent Kurrajong earthquake 

 which came to hand were naturally from the metropolitan 

 area. From the newspaper accounts it appeared that the 

 shock was felt more strongly along the coastal area than 

 in the city and western suburbs. This suggested that the 

 earthquake was of submarine origin. 



The author has recently been working on the problem of 

 earthquake frequency and tidal stresses in the lithosphere. 

 It was natural that he should have made an application of 

 his results to this earthquake. It was found that the tidal 

 stresses were such as to tend to cause rupture on a nearly 

 meridional fault dipping at about 64° to the west. The only 

 considerable fault known in the Sydney district which has 

 a westerly dip is that described by Professor David as the 

 Kurrajong fault. It therefore seemed important to obtain 

 information from this locality. On the second day after 

 the earthquake the writer therefore visited the Kurrajong 

 and made personal inquiries from a number of residents. 

 He found that the shock was much more severe here than 

 in the city t or suburbs. A careful search also enabled him 



