500 



Dr. C. Davison — British Earthquakes. 



distance from land being about 5 or 6 miles. The fault-slip was 

 probably several miles in length, and that its depth was inconsiderable 

 is shown by the closeness of the isoseismal 5 and 4. The rapid decline 

 in the intensity of the shock, of which this closeness is indicative, also 

 characterised the submarine Penzance earthquake of 1904. 



4. Fort William Earthqtiah : May 1th, 1906. — Time of occurrence, 

 8.20 p.m. 



A slight shock felt at Fort William, lasting about 2 seconds, and 

 preceded by a rumbling noise. The earthquake was probably due 

 to a small slip of the northern boundary fault of the Highlands. 



5. Carnarron JEarthqiiahe : June 29'fh, 1906.— Time of occurrence, 

 3,2 a.m.; intensity, 4; centre of disturbed area in lat. 52° 9*2' K., 

 long. 4° 10-7' W. ; number of records 23, from 15 places, and 17 

 negative records from 13 places. (Fig. 2.) 



T-A„ \; 



a.u.m,Q.T-i.5 



Fig. 2.— Carnarvon Earthquake, June 29tli, 1906. 



The continuous line on the map (Fig. 2) represents the boundary of 

 the disturbed area, which is 16 miles long from north-east to south- 

 west, 14^ miles wide, and contains about 182 square miles. Its 

 centre is about 4 miles E. 15° jS'. of Carnarvon, and 1 1 miles E. 40° N. 

 of the centre of the isoseismal 7 of the principal earthquake of 

 June 19th, 1903. The curve is too nearly circular in form, and is not 

 drawn with sufficient accuracy to enable the direction of its longer 

 axis to be given more approximately than north-east and south-west. 



The shock consisted of a single series of vibrations, lasting as a rule 

 only a few seconds. 



The sound, which lasted about 5 seconds, was heard by all the 



