418 PROCEEDmGS OF SECTION E. 



published by the Australasian Association for the Advancement of 

 Science. 



These records are necessarily incomplete. They are principally 

 the reports of postmasters, a body of men to whom, I may say, we owe 

 a very great deal for their obsei-vations of natural phenomena, 

 especially those relating to meteorology. There are, however, such 

 large areas of South Australia which are sparsely populated, and still 

 larger stretches of country in the interior quite uninliabited, that 

 many earthquakes must have occurred without having been perceived, 

 and probably many which have been perceived, especially those of the 

 feebler kind, have remained unreported. 



From the available information, which may be regarded as fairly 

 representing the earthquake phenomena over, at all events, the 

 settled portions of the State, we note tJiat the South Australian earth- 

 quakes during the period 1903 to 1908 were few and of small in- 

 tensity. Their distribution, as is indicated by the accompanying 

 maps, coincides with that of quakes and tremors recorded during tlie 

 last quarter of century. 



On the maps, where the different colours denote different geo- 

 logical formations, localities where earthquakes and tremors have 

 been reported are marked in black, and the shading of the black on 

 these maps, according to its lighter or deeper tone, illustrates the 

 relative fi^equency of seismic disturbances. 



In the last twenty-seven years the greatest number of reported 

 earthquakes is at Beltana, which is situated in the hilly country 

 east of Lake Torrens. This locality reported twenty-six more or less 

 severe tremors during this period. 



Blinman, not far distant, reported twenty during the same 

 period. 



Kapunda and Eudunda, in the Murray Range diftrict, 30 to 40 

 miles east of the head of St. Vincent's Gulf, reported twenty-two and 

 twenty-one respectively. 



An average of one earthquake per year, or less, in our districts 

 <oi greatest seismic movement cannot be considered veiy formidable. 



The only two m.oderately severe earthquakes noted in this State 

 were those of 10th May, 1897, and 19th September, 1902. These are 

 specially indicated on Map 11. Both, but particularly the 1897 quake, 

 were followed by many after shocks in districts near the epicentre. 



In connection with the 1897 earthquake, tremors in the Aacinity 

 of Kingston, on our south-east coast, continued at intei-vals for some 

 months, and all appeared to point to a focus in the ocean somewhere 

 westward of that neighbourhood. 



It has, therefore, been more convenient to indicate the whole of 

 the area affected by this and the 1902 earthquake by black stipple 

 marks. 



Both these earthquakes showed a large epicentral area, and were 

 felt far and wide in all directions. They were recorded from Streaky 

 Bay on our west coast,, right across to Victoria. 



Most of our seismic disturbances, however, have been of a com- 

 paratively small intensity, on the average from IV. to V., on the 

 Rossi Forel scale, and, with few exceptions, were not felt veiy far 

 from the centre of movement. 



